b612
2bf8478639
- 新增日月食中心带、偏食带、阴影足迹、等时线、食分线及升落边界计算，支持极区与混合食拓扑 - 新增日食单时刻阴影求解器、站心状态查询、批量采样和 ΔT 覆盖接口 - 重构恒星与行星月掩路径，补充有限盘面接触、站心修正、掩带宽度、极区投影及升落边界 - 扩展 SVG 与 GeoJSON 输出，支持详细面板、全球/极区/地球投影、边界闭合、时间标记和拓扑签名 - 扩展日月食候选搜索、局地搜索、沙罗序列预计算与范围外推，补充系列锚点和成员一致性校验 - 补齐古历纪年、儒略历独有闰日、多公历候选、历法改革跨日及精确日期运算接口 - 优化 ΔT、章动、恒星时、月球地平线、事件根搜索和本地星历缓存，降低重复计算开销并提升边界稳定
1477 lines
67 KiB
Go
1477 lines
67 KiB
Go
package basic
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import (
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"math"
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"sort"
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"time"
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)
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const (
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solarEclipsePathDefaultStepDays = 1.0 / 1440.0
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solarEclipsePathMinStepDays = 1.0 / 86400.0
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solarEclipsePathMaxSampleCount = 30000
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solarEclipsePathMaxAdaptiveDepth = 20
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solarEclipsePathVelocityStepDays = 1.0 / 1440.0
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// A sample may sit exactly on the horizon; only clearly below it is the
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// central phase unobservable and its duration meaningless.
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solarEclipsePathDurationHorizonToleranceDegrees = 0.1
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// 地球表面上的影锥足迹不可能比地球本身更宽。
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// No shadow footprint on the Earth can be wider than the Earth itself.
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solarEclipsePathMaxPossibleWidthKM = 2 * 6371.0088
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solarEclipsePathDuplicateTimeDays = 1e-10
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// A short segment can still hide a large directional change at high
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// latitude. Use a small relative sagitta tolerance so refinement follows
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// geometry without forcing every path to the finest possible spacing.
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solarEclipsePathAdaptiveCurvatureFraction = 0.02
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solarEclipsePathMinimumCurvatureKM = 2.0
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solarEclipsePartialFootprintDefaultStepDays = 5.0 / 1440.0
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solarEclipseRiseSetDefaultStepDays = 2.0 / 1440.0
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solarEclipsePartialFootprintDefaultBoundaryPoints = 180
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solarEclipsePartialFootprintMinBoundaryPoints = 12
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solarEclipsePartialFootprintMaxBoundaryPoints = 1440
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solarEclipsePartialFootprintPointTolerance = 1e-12
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solarEclipsePartialFootprintIterationLimit = 10
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solarEclipsePartialFootprintMaxPointCount = 2000000
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solarEclipsePartialFootprintTargetSpacingKM = 200.0
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solarEclipseMagnitudeContourMaxValues = 16
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solarEclipsePartialFootprintTransitionIterations = 48
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// An open footprint ends where the axis-parallel line through the shadow
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// radius stops meeting the ellipsoid. The bracket is searched around the
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// converged sampled radius, so a few doublings cover both the outside cut of
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// an on-disc shadow and the inside cut of a shadow whose axis misses the
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// Earth; the bisection below then lands on the tangency point, which sits on
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// the horizon and makes the closing arc exact.
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solarEclipseHorizonEndSearchStep = 1e-5
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solarEclipseHorizonEndSearchLimit = 0.25
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solarEclipseHorizonEndBisectionRounds = 40
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// The band footprints only have to resolve the swept envelope, not the
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// instantaneous rim: consecutive samples may advance far as long as their
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// union still follows the boundary. A grazing event spends most of its
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// contact interval creeping across the terminator, so a 10 s stride there
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// costs hundreds of solves for a few kilometres of travel.
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solarEclipseCentralBandStepDays = 10.0 / 86400.0
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solarEclipseNonCentralBandFallbackStepDays = 60.0 / 86400.0
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solarEclipseNonCentralBandPreciseMaxDurationDays = 20.0 / 1440.0
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solarEclipseCentralBandContactFineStepDays = 1.0 / 86400.0
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solarEclipseCentralBandContactFineWindowDays = 45.0 / 86400.0
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solarEclipseCentralBandBoundaryPoints = 90
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// The union decimates every footprint ring to the union spacing before it
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// merges them, and the result is relaxed afterwards, so solving the band
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// footprints finer than this only buys trigonometry.
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solarEclipseCentralBandTargetSpacingKM = 10.0
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solarEclipseNonCentralTotalBandTargetSpacingKM = 25.0
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solarEclipseCentralLimitTargetSpacingKM = 200.0
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solarEclipseShadowFootprintAdaptiveMaxDepth = 12
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solarEclipseShadowContactSearchStepDays = 10.0 / 1440.0
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solarEclipseShadowContactSearchSpanDays = 0.75
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solarEclipseShadowContactToleranceDays = 1e-9
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solarEclipseMagnitudeContourBoundaryPoints = 180
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solarEclipseMagnitudeContourTargetSpacingKM = 500.0
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solarEclipseMagnitudeContourArcStepDegrees = 4.0
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solarEclipseMagnitudeContourMinArcStepDegrees = 0.01
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solarEclipseMagnitudeContourMaxArcSteps = 2000
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solarEclipseMagnitudeContourTimeScale = 360.0
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solarEclipseMagnitudeContourFallbackBearings = 72
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solarEclipseMagnitudeContourFallbackDistances = 12
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solarEclipseRiseSetBoundaryPoints = 180
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solarEclipseRiseSetCriticalStepDays = 1.0 / 1440.0
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solarEclipseRiseSetDerivativeStepDays = 5.0 / 86400.0
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solarEclipseRiseSetTargetSpacingKM = 500.0
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solarEclipseRiseSetAttachmentDistanceToleranceKM = 5.0
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solarEclipseRiseSetAttachmentTimeToleranceDays = 2.0 / 86400.0
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solarEclipseRiseSetPhaseConnectionLimitKM = 3000.0
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solarEclipseRiseSetTimeEpsilonDays = 1e-8
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)
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type solarEclipseShadowKind uint8
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const (
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solarEclipsePenumbralShadow solarEclipseShadowKind = iota
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solarEclipseCentralShadow
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)
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// SolarEclipsePathOptions 控制日食中心路径采样。
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// SolarEclipsePathOptions controls central solar eclipse path sampling.
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type SolarEclipsePathOptions struct {
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// StepDays 是基础时间采样步长，单位为日；<=0 时使用 1 分钟。
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// StepDays is the base time step in days; values <= 0 use one minute.
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StepDays float64
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// TargetSpacingKM 是相邻中心线点的最大目标地表距离；<=0 时不按距离加密。
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// TargetSpacingKM is the target maximum ground spacing between centerline points; values <= 0 disable spacing refinement.
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TargetSpacingKM float64
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// DeltaTSeconds 显式 ΔT（秒），<=0 用进程级模型；与单时刻阴影层同口径，避免同一张图上
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// 路径几何与瞬时足迹各自使用不同的 ΔT（两者会沿经度错开 0.4651·|ΔΔT|·cosφ 千米）。
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// DeltaTSeconds is an explicit ΔT in seconds; values <= 0 use the process-wide
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// model. The path and the instantaneous footprints of one figure must share it.
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DeltaTSeconds float64
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// SkipCentralBand 表示调用方已经持有同一场日食的完整足迹结果（其中包含
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// CentralBandSegments），本次只求解中心线、南北限界与地平线端点，不重复重建中心食带。
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// 单场日食的中心带足迹是整条链路里最贵的一段，同时取足迹与路径时重复计算会翻倍。
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// SkipCentralBand reports that the caller already holds the full-footprint
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// result for the same eclipse, whose CentralBandSegments are authoritative,
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// so this call only solves the center line, the limits and the contact
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// points instead of rebuilding the central band. The band footprints are the
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// most expensive stage of the pipeline and would otherwise be computed twice
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// by callers that ask for both products.
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SkipCentralBand bool
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}
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// SolarEclipsePathPoint 表示日食路径上的一个地理点。
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// SolarEclipsePathPoint is one geographic point on a solar eclipse path.
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type SolarEclipsePathPoint struct {
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// JDE 是力学时儒略日, TT Julian ephemeris day.
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JDE float64
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// Longitude 经度，东正西负, longitude in degrees, east positive.
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Longitude float64
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// Latitude 纬度，北正南负, latitude in degrees, north positive.
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Latitude float64
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// SunAltitude 太阳高度角，单位度, Sun altitude in degrees.
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SunAltitude float64
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// WidthKM 中心食带宽度，单位千米；仅中心线点有意义；退化地平线切点无法形成稳定成对横截面时为 0。
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// WidthKM is the central path width in kilometers; it is meaningful for centerline points and is 0 at a degenerate horizon contact without a stable paired cross-section.
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WidthKM float64
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}
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// SolarEclipsePathResult 表示一次中心日食的路径数据。
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// SolarEclipsePathResult contains central solar eclipse path data.
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type SolarEclipsePathResult struct {
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// Eclipse 是对应的全局日食结果, related global solar eclipse result.
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Eclipse SolarEclipseResult
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// Greatest 是食甚点/最佳观测点, greatest eclipse point.
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Greatest SolarEclipsePathPoint
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// MaxCentralDurationDays 是中心线上最长的中心食时长（单位为日），并给出其发生位置。
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// 与目录（NASA）口径不同：目录值取食甚点，这里是整条中心线上的最大值。
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// MaxCentralDurationDays is the longest central phase on the center line, in
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// days, with the location where it occurs. The catalogued "central duration"
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// is the value at greatest eclipse; this is the maximum along the track.
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MaxCentralDurationDays float64
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MaxCentralDurationLongitude float64
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MaxCentralDurationLatitude float64
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// CenterLine 是中心线, central line.
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CenterLine []SolarEclipsePathPoint
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// NorthernLimit 是中心食带北界近似线, approximate northern limit of the central path.
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NorthernLimit []SolarEclipsePathPoint
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// SouthernLimit 是中心食带南界近似线, approximate southern limit of the central path.
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SouthernLimit []SolarEclipsePathPoint
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// CentralBandSegments is the authoritative continuous central-band envelope.
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CentralBandSegments [][]SolarEclipsePathPoint
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// CentralBandSampled 表示上面的包络是用采样瞬时足迹重建的（解析包络不适用）。
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// CentralBandSampled reports that the envelope above was reconstructed from
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// the sampled instantaneous footprints because no analytic envelope
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// described this event.
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CentralBandSampled bool
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// StepDays 是实际采用的基础时间采样步长，单位为日。
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// StepDays is the effective base time step in days.
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StepDays float64
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// TargetSpacingKM 是实际采用的目标空间采样距离，单位千米。
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// TargetSpacingKM is the effective target spacing in kilometers.
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TargetSpacingKM float64
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}
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// SolarEclipsePartialFootprintOptions 控制日食偏食半影足迹采样。
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// SolarEclipsePartialFootprintOptions controls solar eclipse penumbral footprint sampling.
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type SolarEclipsePartialFootprintOptions struct {
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// StepDays 是基础时间采样步长，单位为日；<=0 时使用 5 分钟。
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// StepDays is the base time step in days; values <= 0 use five minutes.
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StepDays float64
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// BoundaryPoints 是每个瞬时半影边界的角向采样点数；<=0 时使用 180。
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// BoundaryPoints is the angular sample count for each instantaneous penumbral boundary; values <= 0 use 180.
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BoundaryPoints int
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// CentralShadowStepDays 是本影/反本影瞬时足迹的时间步长，单位为日；<=0 时不计算。
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// CentralShadowStepDays is the umbral/antumbral footprint step in days; values <= 0 disable it.
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CentralShadowStepDays float64
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// RiseSetStepDays 独立采样地平阶段曲线；<=0 时使用 2 分钟。
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// RiseSetStepDays samples horizon curves independently; values <=0 use two minutes.
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RiseSetStepDays float64
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// DisableRiseSetCurves 禁用六类日升日落阶段边界。
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// DisableRiseSetCurves disables the six sunrise/sunset boundaries.
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DisableRiseSetCurves bool
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// MagnitudeValues 是要计算的地方最大食分等值线；空值不计算，线条使用独立的自适应空间采样。
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// MagnitudeValues requests local maximum-magnitude contours; empty disables them, and contours use independent adaptive spatial sampling.
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MagnitudeValues []float64
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// GreatestTimeValues 是要计算的地方食甚时刻等值线取值（TT 儒略日，最多 64 条，超出按时间截断）；
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// 只有确实存在该时刻食甚轨迹的取值才会出现在结果里，所以返回条数可能少于请求条数。
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// 空值时改用 GreatestTimeStep。每条等时线用固定时刻的残差零集延拓，成本正比于曲线长度而不是可见域面积。
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// GreatestTimeValues requests local greatest-eclipse time isolines as TT Julian ephemeris days
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// (at most 64, truncated in time order); when empty, GreatestTimeStep is used instead. Each
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// isochrone is continued along the zero set of a fixed-instant residual, so the cost scales
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// with curve length rather than with the visible area.
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GreatestTimeValues []float64
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// GreatestTimeStep 是等时线间隔；仅在 GreatestTimeValues 为空时生效，非正值不计算等时线。
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// 取值对齐到 UTC 整刻度并覆盖地球范围的偏食窗口，最多 64 条；显示层若需要按展示时区对齐，
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// 应自行生成时刻后改用 GreatestTimeValues。
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// GreatestTimeStep is the isochrone interval; it applies only when GreatestTimeValues is empty,
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// and non-positive values disable the isolines. Levels align to UTC ticks across the global
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// partial-eclipse window, at most 64; display layers that need the viewing timezone grid should
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// generate the instants themselves and pass GreatestTimeValues instead.
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GreatestTimeStep time.Duration
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// DeltaTSeconds 显式 ΔT（秒），<=0 用进程级模型；与单时刻阴影层同口径。
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// DeltaTSeconds is an explicit ΔT in seconds; values <= 0 use the process-wide model.
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DeltaTSeconds float64
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}
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// SolarEclipsePartialAreaOptions 是 SolarEclipsePartialFootprintOptions 的兼容别名。
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// SolarEclipsePartialAreaOptions is a compatibility alias for SolarEclipsePartialFootprintOptions.
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type SolarEclipsePartialAreaOptions = SolarEclipsePartialFootprintOptions
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// SolarEclipsePartialFootprint 表示某一时刻的半影足迹边界。
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// SolarEclipsePartialFootprint is the penumbral footprint boundary at one instant.
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type SolarEclipsePartialFootprint struct {
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// JDE 是力学时儒略日, TT Julian ephemeris day.
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JDE float64
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// Boundaries 是半影边界分段；反经线或无效投影会拆成多段。
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// Boundaries are segmented penumbral boundary polylines, split at invalid projections or the antimeridian.
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Boundaries [][]SolarEclipsePathPoint
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// Closed 表示 Boundaries 是否构成一个闭合边界。
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// Closed indicates whether Boundaries form one closed boundary.
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Closed bool
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// HorizonEnds 是未闭合边界两端延伸到地平圈的擦地点，顺序与 Boundaries 的走向一致
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// （HorizonEnds[0] 贴近边界起点，HorizonEnds[1] 贴近边界终点）；边界自身闭合时为空。
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// 被地平线切断的瞬时阴影区域由「物理边界 + 两个擦地点之间的地平弧」闭合；擦地点是
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// 阴影锥面与地表的切点，其太阳高度为 0，所以该闭合弧是精确结果而不是启发式。
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// HorizonEnds are the two limb-grazing points where an open boundary reaches the
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// horizon, ordered like Boundaries (HorizonEnds[0] near the boundary start,
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// HorizonEnds[1] near its end); empty when the boundary closes on itself. A region
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// cut by the horizon is closed by the physical boundary plus the horizon arc
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// between these grazing points, which are exact cone-surface tangency points with
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// zero solar altitude rather than a heuristic.
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HorizonEnds []SolarEclipsePathPoint
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}
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// SolarEclipsePartialFootprintsResult 表示一次日食的偏食半影足迹序列。
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// SolarEclipsePartialFootprintsResult contains penumbral footprint samples for a solar eclipse.
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type SolarEclipsePartialFootprintsResult struct {
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// Eclipse 是对应的全局日食结果, related global solar eclipse result.
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Eclipse SolarEclipseResult
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// Footprints 是按时间采样的瞬时半影足迹, sampled instantaneous penumbral footprints.
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Footprints []SolarEclipsePartialFootprint
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// CentralShadowFootprints 是按时间采样的本影/反本影足迹。
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// CentralShadowFootprints are sampled umbral/antumbral footprints.
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CentralShadowFootprints []SolarEclipsePartialFootprint
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// CentralBandFootprints 是始终计算的低成本本影/反本影端部样本，用于闭合中心食带。
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// CentralBandFootprints are always-computed lightweight umbral/antumbral end samples used to close the central band.
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CentralBandFootprints []SolarEclipsePartialFootprint
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// CentralBandSegments 是地方中心食条件的连续闭合包络。
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// CentralBandSegments are continuous closed envelopes of the local central-eclipse condition.
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CentralBandSegments [][]SolarEclipsePathPoint
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// CentralBandSampled 表示上面的包络是用采样瞬时足迹重建的（解析包络不适用）。
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// CentralBandSampled reports that CentralBandSegments were reconstructed from
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// the sampled instantaneous footprints because no analytic envelope applied.
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CentralBandSampled bool
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// CentralBandHorizonClosures 是两限界掠地事件中分别连接首尾两侧限界的食甚地平线弧。
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// CentralBandHorizonClosures are the greatest-at-horizon arcs joining both ends of a grazing two-limit event.
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CentralBandHorizonClosures [][]SolarEclipsePathPoint
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// PartialBandContours 是地方最大食分等于零的连续可见包络，用于与日出日落边界闭合偏食可见域。
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// PartialBandContours are the continuous zero local-maximum-magnitude envelopes used with horizon boundaries to close the partial-eclipse visibility region.
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PartialBandContours [][]SolarEclipsePathPoint
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// MagnitudeContours 是按食分值采样的两侧等值线。
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// MagnitudeContours are sampled two-sided local maximum-magnitude contours.
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MagnitudeContours []SolarEclipseMagnitudeContour
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// GreatestTimeContours 是按食甚时刻采样的等时线。
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// GreatestTimeContours are sampled local greatest-eclipse time isolines.
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GreatestTimeContours []SolarEclipseGreatestTimeContour
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// RiseSetCurves 是初亏、食甚和复圆分别发生在日出或日落时的六类边界。
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// RiseSetCurves are the six boundaries where local start, greatest, or end occurs at sunrise or sunset.
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RiseSetCurves []SolarEclipseRiseSetCurve
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// RiseSetTopologyDegraded 表示请求了升落曲线但六类边界未通过拓扑校验（每曲线 16 段、
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// 总计 32 段的段数上限，端点共享与时间单调），RiseSetCurves 是被截断的降级结果。
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// RiseSetTopologyDegraded reports that the requested rise/set curves failed the
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// topology audit (the 16-segment per-curve and 32-segment total caps, shared
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// endpoints and monotonic times), so RiseSetCurves is a truncated result.
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RiseSetTopologyDegraded bool
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// P1-P4 是半影与地球的外切/内切接触点；不存在的内切点保持零值。
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// P1-P4 are external/internal penumbral contacts; absent internal contacts remain zero.
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P1 SolarEclipsePathPoint
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P2 SolarEclipsePathPoint
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P3 SolarEclipsePathPoint
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P4 SolarEclipsePathPoint
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// U1-U4 是本影/反本影与地球的外切/内切接触点；不存在时保持零值。
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// U1-U4 are external/internal umbral/antumbral contacts; absent contacts remain zero.
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U1 SolarEclipsePathPoint
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U2 SolarEclipsePathPoint
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U3 SolarEclipsePathPoint
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U4 SolarEclipsePathPoint
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// StepDays 是实际采用的基础时间采样步长，单位为日。
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// StepDays is the effective base time step in days.
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StepDays float64
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// BoundaryPoints 是实际采用的边界角向采样点数。
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// BoundaryPoints is the effective angular sample count for each boundary.
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||
BoundaryPoints int
|
||
// CentralShadowStepDays 是本影/反本影足迹的实际采样步长；0 表示未计算。
|
||
// CentralShadowStepDays is the effective umbral/antumbral footprint step; zero means disabled.
|
||
CentralShadowStepDays float64
|
||
// CentralBandStepDays 是中心食带足迹的最细实际采样步长。
|
||
// CentralBandStepDays is the finest effective sampling step for central-band footprints.
|
||
CentralBandStepDays float64
|
||
}
|
||
|
||
// SolarEclipseGreatestTimeContour 是一个固定地方食甚时刻的等值线支路集合。
|
||
// SolarEclipseGreatestTimeContour contains the continuous branches of one fixed local greatest-eclipse time.
|
||
type SolarEclipseGreatestTimeContour struct {
|
||
// JDE 是该等值线表示的力学时儒略日，也就是各支路上地方食甚发生的时刻。
|
||
// JDE is the TT Julian ephemeris day represented by this contour, the local greatest-eclipse instant along every branch.
|
||
JDE float64
|
||
// Segments 是该时刻的连续等时线支路；一条支路两端止于地平线或偏食可见域边界。
|
||
// Segments are continuous isochrone branches; each branch ends at the horizon or the partial-visibility boundary.
|
||
Segments [][]SolarEclipsePathPoint
|
||
}
|
||
|
||
// SolarEclipseMagnitudeContour 是一条地方最大食分等值线的连续支路集合。
|
||
// SolarEclipseMagnitudeContour contains the continuous branches of one local maximum-magnitude contour.
|
||
type SolarEclipseMagnitudeContour struct {
|
||
// Magnitude 是该等值线表示的地方最大食分。
|
||
// Magnitude is the local maximum eclipse magnitude represented by this contour.
|
||
Magnitude float64
|
||
// Segments 是地方最大食分等值线的连续支路；临近地平线时局部食甚时刻可以沿空间支路折返。
|
||
// Segments are continuous local maximum-magnitude branches; local greatest times may fold along a spatial branch near the horizon.
|
||
Segments [][]SolarEclipsePathPoint
|
||
// NorthernLimit 和 SouthernLimit 保留两侧中心食等值线的兼容视图。
|
||
// NorthernLimit and SouthernLimit retain the compatibility view for two-sided central-eclipse contours.
|
||
NorthernLimit []SolarEclipsePathPoint
|
||
SouthernLimit []SolarEclipsePathPoint
|
||
}
|
||
|
||
// SolarEclipseRiseSetCurve 是一种局部阶段与日出/日落同时发生的边界。
|
||
// SolarEclipseRiseSetCurve is one boundary where a local phase coincides with sunrise or sunset.
|
||
type SolarEclipseRiseSetCurve struct {
|
||
// Phase 是与日出或日落同时发生的局部日食阶段。
|
||
// Phase is the local eclipse phase coinciding with sunrise or sunset.
|
||
Phase RiseSetPhase
|
||
// Direction 标识太阳正在升起还是落下。
|
||
// Direction identifies whether the Sun is rising or setting.
|
||
Direction RiseSetDirection
|
||
// Segments 是反经线和支路跳变安全分段后的边界采样。
|
||
// Segments are boundary samples split safely at the antimeridian and branch changes.
|
||
Segments [][]SolarEclipsePathPoint
|
||
}
|
||
|
||
// SolarEclipsePartialAreaResult 是 SolarEclipsePartialFootprintsResult 的兼容别名。
|
||
// SolarEclipsePartialAreaResult is a compatibility alias for SolarEclipsePartialFootprintsResult.
|
||
type SolarEclipsePartialAreaResult = SolarEclipsePartialFootprintsResult
|
||
|
||
// SolarEclipseCentralPath 计算给定近朔时刻附近的日食中心路径，默认使用 NASA bulletin Split-K 模型。
|
||
// SolarEclipseCentralPath computes the central path near the given new-moon seed, using NASA bulletin Split-K by default.
|
||
func SolarEclipseCentralPath(seedJDE float64, options SolarEclipsePathOptions) SolarEclipsePathResult {
|
||
return SolarEclipseCentralPathNASABulletinSplitK(seedJDE, options)
|
||
}
|
||
|
||
// SolarEclipseCentralPathIAUSingleK 计算日食中心路径，使用 IAU Single-K 模型。
|
||
// SolarEclipseCentralPathIAUSingleK computes the central path with the IAU Single-K model.
|
||
func SolarEclipseCentralPathIAUSingleK(seedJDE float64, options SolarEclipsePathOptions) SolarEclipsePathResult {
|
||
return solarEclipseCentralPath(seedJDE, SolarEclipseModelIAUSingleK, options)
|
||
}
|
||
|
||
// SolarEclipseCentralPathNASABulletinSplitK 计算日食中心路径，使用 NASA bulletin Split-K 模型。
|
||
// SolarEclipseCentralPathNASABulletinSplitK computes the central path with the NASA bulletin Split-K model.
|
||
func SolarEclipseCentralPathNASABulletinSplitK(seedJDE float64, options SolarEclipsePathOptions) SolarEclipsePathResult {
|
||
return solarEclipseCentralPath(seedJDE, SolarEclipseModelNASABulletinSplitK, options)
|
||
}
|
||
|
||
// SolarEclipsePartialFootprints 计算给定近朔时刻附近的日食偏食半影足迹序列，默认使用 NASA bulletin Split-K 模型。
|
||
// SolarEclipsePartialFootprints computes penumbral footprint samples near the given new-moon seed, using NASA bulletin Split-K by default.
|
||
func SolarEclipsePartialFootprints(seedJDE float64, options SolarEclipsePartialFootprintOptions) SolarEclipsePartialFootprintsResult {
|
||
return SolarEclipsePartialFootprintsNASABulletinSplitK(seedJDE, options)
|
||
}
|
||
|
||
// SolarEclipsePartialFootprintsIAUSingleK 计算日食偏食半影足迹序列，使用 IAU Single-K 模型。
|
||
// SolarEclipsePartialFootprintsIAUSingleK computes penumbral footprint samples with the IAU Single-K model.
|
||
func SolarEclipsePartialFootprintsIAUSingleK(seedJDE float64, options SolarEclipsePartialFootprintOptions) SolarEclipsePartialFootprintsResult {
|
||
return solarEclipsePartialFootprints(seedJDE, SolarEclipseModelIAUSingleK, options)
|
||
}
|
||
|
||
// SolarEclipsePartialFootprintsNASABulletinSplitK 计算日食偏食半影足迹序列，使用 NASA bulletin Split-K 模型。
|
||
// SolarEclipsePartialFootprintsNASABulletinSplitK computes penumbral footprint samples with the NASA bulletin Split-K model.
|
||
func SolarEclipsePartialFootprintsNASABulletinSplitK(seedJDE float64, options SolarEclipsePartialFootprintOptions) SolarEclipsePartialFootprintsResult {
|
||
return solarEclipsePartialFootprints(seedJDE, SolarEclipseModelNASABulletinSplitK, options)
|
||
}
|
||
|
||
// SolarEclipsePartialArea 计算日食偏食半影足迹序列，是 SolarEclipsePartialFootprints 的兼容包装。
|
||
// SolarEclipsePartialArea computes penumbral footprint samples and is a compatibility wrapper for SolarEclipsePartialFootprints.
|
||
func SolarEclipsePartialArea(seedJDE float64, options SolarEclipsePartialAreaOptions) SolarEclipsePartialAreaResult {
|
||
return SolarEclipsePartialFootprints(seedJDE, options)
|
||
}
|
||
|
||
// SolarEclipsePartialAreaIAUSingleK 计算日食偏食半影足迹序列，是 SolarEclipsePartialFootprintsIAUSingleK 的兼容包装。
|
||
// SolarEclipsePartialAreaIAUSingleK is a compatibility wrapper for SolarEclipsePartialFootprintsIAUSingleK.
|
||
func SolarEclipsePartialAreaIAUSingleK(seedJDE float64, options SolarEclipsePartialAreaOptions) SolarEclipsePartialAreaResult {
|
||
return SolarEclipsePartialFootprintsIAUSingleK(seedJDE, options)
|
||
}
|
||
|
||
// SolarEclipsePartialAreaNASABulletinSplitK 计算日食偏食半影足迹序列，是 SolarEclipsePartialFootprintsNASABulletinSplitK 的兼容包装。
|
||
// SolarEclipsePartialAreaNASABulletinSplitK is a compatibility wrapper for SolarEclipsePartialFootprintsNASABulletinSplitK.
|
||
func SolarEclipsePartialAreaNASABulletinSplitK(seedJDE float64, options SolarEclipsePartialAreaOptions) SolarEclipsePartialAreaResult {
|
||
return SolarEclipsePartialFootprintsNASABulletinSplitK(seedJDE, options)
|
||
}
|
||
|
||
func solarEclipseCentralPath(seedJDE float64, model SolarEclipseRadiusModel, options SolarEclipsePathOptions) SolarEclipsePathResult {
|
||
options = normalizeSolarEclipsePathOptions(options)
|
||
newMoonJDE := CalcMoonSHByJDE(seedJDE, 0)
|
||
solver := newSolarEclipseSolver(newMoonJDE, model).withDeltaTSeconds(options.DeltaTSeconds)
|
||
result := solver.eclipseResult()
|
||
path := SolarEclipsePathResult{
|
||
Eclipse: result,
|
||
StepDays: options.StepDays,
|
||
TargetSpacingKM: options.TargetSpacingKM,
|
||
}
|
||
if !result.HasCentral {
|
||
return path
|
||
}
|
||
|
||
greatest, ok := solver.centralPathPointAt(result.GreatestEclipse)
|
||
if !ok {
|
||
greatest = SolarEclipsePathPoint{
|
||
JDE: result.GreatestEclipse,
|
||
Longitude: result.GreatestLongitude,
|
||
Latitude: result.GreatestLatitude,
|
||
WidthKM: result.PathWidthKM,
|
||
SunAltitude: solarEclipseSunAltitudeAtGreatest(
|
||
result.GreatestEclipse,
|
||
result.GreatestLongitude,
|
||
result.GreatestLatitude,
|
||
solver.besselAxisAt(result.GreatestEclipse).gst,
|
||
) / rad,
|
||
}
|
||
}
|
||
greatest.Longitude = result.GreatestLongitude
|
||
greatest.Latitude = result.GreatestLatitude
|
||
greatest.WidthKM = result.PathWidthKM
|
||
path.Greatest = greatest
|
||
|
||
samplingOptions := options
|
||
samplingOptions.TargetSpacingKM = 0
|
||
centerLine, stepDays := solver.centralPathPoints(
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
result.GreatestEclipse,
|
||
samplingOptions,
|
||
)
|
||
centerLine = solver.attachCentralAxisContactPoints(
|
||
centerLine, result.CentralBeginOnEarth, result.CentralEndOnEarth,
|
||
)
|
||
if result.Type == SolarEclipseHybrid {
|
||
centerLine = solver.attachCentralMagnitudeOneTransitions(centerLine)
|
||
}
|
||
if options.TargetSpacingKM > 0 {
|
||
centerLine = solver.refineCentralPathSpacing(centerLine, options.TargetSpacingKM)
|
||
}
|
||
path.StepDays = stepDays
|
||
// 每对横截面只解一次：限界线与宽度都取自同一份配对结果，重复求解是这条链上最大的
|
||
// 单点分配与耗时来源。
|
||
northernLimit, southernLimit, pairedLimits := solver.centralPathLimitPairs(centerLine)
|
||
path.NorthernLimit, path.SouthernLimit = solarEclipseFilterCentralPathLimits(
|
||
northernLimit, southernLimit, pairedLimits,
|
||
)
|
||
// The paired-limit width runs first, then the contact pass restores the exact
|
||
// U1/U4 samples, whose cross-section is solved from the contact pair rather
|
||
// than from the interior samples.
|
||
solver.setCenterLinePairWidths(
|
||
centerLine, result.Centrality, northernLimit, southernLimit, pairedLimits,
|
||
)
|
||
if result.Centrality == SolarEclipseCentralTwoLimits {
|
||
// A one-limit event has no paired cross-section at all, so every sample
|
||
// keeps the 0 that the catalogues also print for it.
|
||
setSolarEclipseCentralContactWidths(centerLine, path.NorthernLimit, path.SouthernLimit)
|
||
}
|
||
path.CenterLine = centerLine
|
||
path.MaxCentralDurationDays, path.MaxCentralDurationLongitude, path.MaxCentralDurationLatitude =
|
||
solver.centralPathMaxCentralDuration(centerLine)
|
||
// A two-limit central eclipse starts and ends at the external umbral
|
||
// contacts, where the northern and southern limits meet. The center line
|
||
// begins later because its Earth-axis intersection is undefined before the
|
||
// axis reaches the surface. Add those exact contact points so consumers do
|
||
// not close the band across the first/last coarse center-line samples.
|
||
if result.Type != SolarEclipseHybrid &&
|
||
result.Centrality == SolarEclipseCentralTwoLimits && len(path.NorthernLimit) > 0 {
|
||
first, last, contactsOK := solver.shadowContactPair(
|
||
result.GreatestEclipse, solarEclipseCentralShadow, false,
|
||
)
|
||
if contactsOK {
|
||
// The open footprint endpoints before the axis reaches the Earth are
|
||
// horizon branches, not the two side limits. Appending them here
|
||
// makes one side turn back and self-intersect near U1/U4. The exact
|
||
// contact points and the first/last cross-sections form the required
|
||
// short end caps without introducing that false branch.
|
||
path.NorthernLimit = append([]SolarEclipsePathPoint{first}, path.NorthernLimit...)
|
||
path.SouthernLimit = append([]SolarEclipsePathPoint{first}, path.SouthernLimit...)
|
||
path.NorthernLimit = append(path.NorthernLimit, last)
|
||
path.SouthernLimit = append(path.SouthernLimit, last)
|
||
}
|
||
}
|
||
path.NorthernLimit, path.SouthernLimit = solver.refineCentralPathLimitSpacing(
|
||
path.NorthernLimit,
|
||
path.SouthernLimit,
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
solarEclipseCentralLimitTargetSpacingKM,
|
||
)
|
||
if options.SkipCentralBand {
|
||
return path
|
||
}
|
||
// Generate the same continuous envelope exposed by the full-footprint API
|
||
// so path-only callers cannot reconstruct a different polar ribbon.
|
||
band, _ := solver.centralBandWithResult(result, normalizeSolarEclipsePartialFootprintOptions(SolarEclipsePartialFootprintOptions{
|
||
StepDays: options.StepDays, BoundaryPoints: 96, DisableRiseSetCurves: true,
|
||
}))
|
||
path.CentralBandSegments = band.CentralBandSegments
|
||
path.CentralBandSampled = band.CentralBandSampled
|
||
return path
|
||
}
|
||
|
||
func (solver solarEclipseSolver) attachCentralMagnitudeOneTransitions(
|
||
points []SolarEclipsePathPoint,
|
||
) []SolarEclipsePathPoint {
|
||
for _, transition := range solver.centralMagnitudeOneTransitions(points) {
|
||
duplicate := false
|
||
for _, point := range points {
|
||
if math.Abs(point.JDE-transition.JDE) <= solarEclipsePathDuplicateTimeDays {
|
||
duplicate = true
|
||
break
|
||
}
|
||
}
|
||
if !duplicate {
|
||
points = append(points, transition)
|
||
}
|
||
}
|
||
sort.Slice(points, func(first, second int) bool { return points[first].JDE < points[second].JDE })
|
||
return normalizeSolarEclipsePathPointSeries(points)
|
||
}
|
||
|
||
func normalizeSolarEclipsePathOptions(options SolarEclipsePathOptions) SolarEclipsePathOptions {
|
||
if options.StepDays <= 0 || math.IsNaN(options.StepDays) || math.IsInf(options.StepDays, 0) {
|
||
options.StepDays = solarEclipsePathDefaultStepDays
|
||
}
|
||
if options.StepDays < solarEclipsePathMinStepDays {
|
||
options.StepDays = solarEclipsePathMinStepDays
|
||
}
|
||
if options.TargetSpacingKM <= 0 || math.IsNaN(options.TargetSpacingKM) || math.IsInf(options.TargetSpacingKM, 0) {
|
||
options.TargetSpacingKM = 0
|
||
}
|
||
return options
|
||
}
|
||
|
||
func solarEclipsePartialFootprints(
|
||
seedJDE float64,
|
||
model SolarEclipseRadiusModel,
|
||
options SolarEclipsePartialFootprintOptions,
|
||
) SolarEclipsePartialFootprintsResult {
|
||
return solarEclipsePartialFootprintsWithResult(
|
||
seedJDE, model, options, solarEclipseWithDeltaT(seedJDE, model, options.DeltaTSeconds),
|
||
)
|
||
}
|
||
|
||
func solarEclipsePartialFootprintsWithResult(
|
||
seedJDE float64,
|
||
model SolarEclipseRadiusModel,
|
||
options SolarEclipsePartialFootprintOptions,
|
||
result SolarEclipseResult,
|
||
) SolarEclipsePartialFootprintsResult {
|
||
options = normalizeSolarEclipsePartialFootprintOptions(options)
|
||
footprintsResult := SolarEclipsePartialFootprintsResult{
|
||
Eclipse: result,
|
||
StepDays: options.StepDays,
|
||
BoundaryPoints: options.BoundaryPoints,
|
||
CentralShadowStepDays: options.CentralShadowStepDays,
|
||
}
|
||
if !result.HasPartial {
|
||
return footprintsResult
|
||
}
|
||
|
||
newMoonJDE := CalcMoonSHByJDE(seedJDE, 0)
|
||
solver := newSolarEclipseSolver(newMoonJDE, model).withDeltaTSeconds(options.DeltaTSeconds)
|
||
footprintsResult, totalMagnitudeOneSegments := solver.centralBandWithResult(result, options)
|
||
// Partial and central-shadow sweeps used to enforce the point budget
|
||
// independently. A high-resolution request could therefore allocate
|
||
// nearly two budgets for each sweep before the caller saw the result.
|
||
// Reserve the already-built central-band samples and share the remaining
|
||
// budget between the main time series before either sweep is generated.
|
||
partialTimes, _ := solarEclipseMovingDiskEngine().sampleTimes(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.GreatestEclipse,
|
||
options.StepDays,
|
||
)
|
||
var shadowTimes []float64
|
||
if options.CentralShadowStepDays > 0 &&
|
||
footprintsResult.U1.JDE != 0 && footprintsResult.U4.JDE != 0 {
|
||
shadowTimes, _ = solarEclipseMovingDiskEngine().sampleTimes(
|
||
footprintsResult.U1.JDE,
|
||
footprintsResult.U4.JDE,
|
||
result.GreatestEclipse,
|
||
options.CentralShadowStepDays,
|
||
)
|
||
}
|
||
options.BoundaryPoints = solarEclipseSharedBoundaryPoints(
|
||
options.BoundaryPoints,
|
||
len(partialTimes),
|
||
len(shadowTimes),
|
||
solarEclipseFootprintPointCount(footprintsResult.CentralBandFootprints),
|
||
)
|
||
footprintsResult.BoundaryPoints = options.BoundaryPoints
|
||
if !options.DisableRiseSetCurves {
|
||
footprintsResult.PartialBandContours = solver.magnitudeContourSegments(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
result.GreatestEclipse,
|
||
0,
|
||
options.StepDays,
|
||
false,
|
||
)
|
||
}
|
||
footprints, stepDays, effectiveBoundaryPoints := solver.partialFootprints(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.GreatestEclipse,
|
||
options,
|
||
)
|
||
footprintsResult.StepDays = stepDays
|
||
footprintsResult.Footprints = footprints
|
||
if effectiveBoundaryPoints > footprintsResult.BoundaryPoints {
|
||
footprintsResult.BoundaryPoints = effectiveBoundaryPoints
|
||
}
|
||
if options.CentralShadowStepDays > 0 &&
|
||
footprintsResult.U1.JDE != 0 && footprintsResult.U4.JDE != 0 {
|
||
var effectiveShadowBoundaryPoints int
|
||
footprintsResult.CentralShadowFootprints, footprintsResult.CentralShadowStepDays, effectiveShadowBoundaryPoints = solver.shadowFootprints(
|
||
footprintsResult.U1.JDE,
|
||
footprintsResult.U4.JDE,
|
||
result.GreatestEclipse,
|
||
options.CentralShadowStepDays,
|
||
options.BoundaryPoints,
|
||
solarEclipseCentralShadow,
|
||
)
|
||
if effectiveShadowBoundaryPoints > footprintsResult.BoundaryPoints {
|
||
footprintsResult.BoundaryPoints = effectiveShadowBoundaryPoints
|
||
}
|
||
}
|
||
footprintsResult.MagnitudeContours = solver.magnitudeContours(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
result.GreatestEclipse,
|
||
options,
|
||
result.Magnitude,
|
||
result.Type == SolarEclipseHybrid,
|
||
totalMagnitudeOneSegments,
|
||
)
|
||
greatestTimeOptions := options
|
||
if len(greatestTimeOptions.GreatestTimeValues) == 0 && greatestTimeOptions.GreatestTimeStep > 0 {
|
||
levels := greatestTimeContourAlignedLevels(
|
||
result.PartialBeginOnEarth, result.PartialEndOnEarth,
|
||
greatestTimeOptions.GreatestTimeStep, greatestTimeContourMaxLevels,
|
||
)
|
||
greatestTimeOptions.GreatestTimeValues = make([]float64, 0, len(levels))
|
||
for _, level := range levels {
|
||
greatestTimeOptions.GreatestTimeValues = append(greatestTimeOptions.GreatestTimeValues, level.tt)
|
||
}
|
||
}
|
||
footprintsResult.GreatestTimeContours = solver.greatestTimeContours(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
greatestTimeOptions,
|
||
)
|
||
return footprintsResult
|
||
}
|
||
|
||
func (solver solarEclipseSolver) centralBandWithResult(
|
||
result SolarEclipseResult,
|
||
options SolarEclipsePartialFootprintOptions,
|
||
) (SolarEclipsePartialFootprintsResult, [][]SolarEclipsePathPoint) {
|
||
footprintsResult := SolarEclipsePartialFootprintsResult{
|
||
Eclipse: result,
|
||
StepDays: options.StepDays,
|
||
BoundaryPoints: options.BoundaryPoints,
|
||
CentralShadowStepDays: options.CentralShadowStepDays,
|
||
}
|
||
if !result.HasPartial {
|
||
return footprintsResult, nil
|
||
}
|
||
|
||
var totalMagnitudeOneSegments [][]SolarEclipsePathPoint
|
||
var nonCentralRiseSetCurves []SolarEclipseRiseSetCurve
|
||
nonCentralRiseSetComplete := true
|
||
if solver.attachCentralBandContacts(&footprintsResult, result) {
|
||
solver.attachCentralBandFootprints(&footprintsResult, result)
|
||
if result.Centrality == SolarEclipseNonCentral {
|
||
totalMagnitudeOneSegments, nonCentralRiseSetCurves, nonCentralRiseSetComplete =
|
||
solver.nonCentralCentralBandEnvelope(result, options, &footprintsResult)
|
||
}
|
||
}
|
||
if result.Type == SolarEclipseTotal && result.Centrality == SolarEclipseCentralTwoLimits {
|
||
totalMagnitudeOneSegments = solver.magnitudeContourSegmentsWithSpacing(
|
||
result.PartialBeginOnEarth, result.PartialEndOnEarth,
|
||
result.CentralBeginOnEarth, result.CentralEndOnEarth,
|
||
result.GreatestEclipse, 1, options.StepDays, false,
|
||
solarEclipseTotalEnvelopeTargetSpacingKM,
|
||
)
|
||
}
|
||
// The rise/set curves are a presentation option, but the precise central
|
||
// envelope still needs their roots to close grazing annular/total paths.
|
||
// Compute the small internal set unconditionally and only suppress it from
|
||
// the returned result when requested.
|
||
riseSetCurves, riseSetComplete := solver.centralBandRiseSetCurves(
|
||
result, options, nonCentralRiseSetCurves, nonCentralRiseSetComplete,
|
||
)
|
||
if !options.DisableRiseSetCurves {
|
||
footprintsResult.RiseSetCurves = riseSetCurves
|
||
// 请求了升落曲线但拓扑校验未通过：返回的是被截断的降级结果，必须显式标记。
|
||
footprintsResult.RiseSetTopologyDegraded = len(riseSetCurves) > 0 && !riseSetComplete
|
||
}
|
||
solver.attachCentralBandClosureEnvelope(
|
||
result, &footprintsResult, riseSetCurves, totalMagnitudeOneSegments,
|
||
)
|
||
solver.attachCentralBandFallbackSweep(result, &footprintsResult, riseSetCurves)
|
||
return footprintsResult, totalMagnitudeOneSegments
|
||
}
|
||
|
||
// attachCentralBandContacts 求半影与本影/反本影的外切/内切接触点，并报告本影接触对能否
|
||
// 支撑中心带采样：本影不存在或退化的抛物接触会让整个中心带支路没有意义。
|
||
func (solver solarEclipseSolver) attachCentralBandContacts(
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
result SolarEclipseResult,
|
||
) bool {
|
||
contactSolver := solver
|
||
contactSolver.exactCentralContact = result.Centrality == SolarEclipseNonCentral
|
||
footprintsResult.P1, footprintsResult.P4, _ = contactSolver.shadowContactPair(
|
||
result.GreatestEclipse, solarEclipsePenumbralShadow, false,
|
||
)
|
||
footprintsResult.P2, footprintsResult.P3, _ = contactSolver.shadowContactPair(
|
||
result.GreatestEclipse, solarEclipsePenumbralShadow, true,
|
||
)
|
||
if result.Type != SolarEclipsePartial {
|
||
footprintsResult.U1, footprintsResult.U4, _ = contactSolver.shadowContactPair(
|
||
result.GreatestEclipse, solarEclipseCentralShadow, false,
|
||
)
|
||
footprintsResult.U2, footprintsResult.U3, _ = contactSolver.shadowContactPair(
|
||
result.GreatestEclipse, solarEclipseCentralShadow, true,
|
||
)
|
||
return footprintsResult.U1.JDE != 0 && footprintsResult.U4.JDE != 0
|
||
}
|
||
return false
|
||
}
|
||
|
||
// attachCentralBandFootprints 采样本影/反本影端帽足迹，非中心食的时长决定用哪一档步长。
|
||
func (solver solarEclipseSolver) attachCentralBandFootprints(
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
result SolarEclipseResult,
|
||
) {
|
||
bandStepDays := solarEclipseCentralBandStepDays
|
||
if result.Centrality == SolarEclipseNonCentral {
|
||
centralDuration := footprintsResult.U4.JDE - footprintsResult.U1.JDE
|
||
if centralDuration > solarEclipseNonCentralBandPreciseMaxDurationDays {
|
||
bandStepDays = solarEclipseNonCentralBandFallbackStepDays
|
||
}
|
||
}
|
||
footprintsResult.CentralBandFootprints, footprintsResult.CentralBandStepDays = solver.centralBandFootprintsWithStep(
|
||
footprintsResult.U1.JDE,
|
||
footprintsResult.U2.JDE,
|
||
footprintsResult.U3.JDE,
|
||
footprintsResult.U4.JDE,
|
||
result.GreatestEclipse,
|
||
bandStepDays,
|
||
)
|
||
}
|
||
|
||
// nonCentralCentralBandEnvelope 求解轴不入地的中心食带：先试解析包络，覆盖不足时退回采样
|
||
// 瞬时足迹并集；同时返回该支路使用的升落曲线与 magnitude-one 等值线。
|
||
func (solver solarEclipseSolver) nonCentralCentralBandEnvelope(
|
||
result SolarEclipseResult,
|
||
options SolarEclipsePartialFootprintOptions,
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
) ([][]SolarEclipsePathPoint, []SolarEclipseRiseSetCurve, bool) {
|
||
var totalMagnitudeOneSegments [][]SolarEclipsePathPoint
|
||
var nonCentralRiseSetCurves []SolarEclipseRiseSetCurve
|
||
nonCentralRiseSetComplete := true
|
||
if result.Centrality == SolarEclipseNonCentral {
|
||
riseSetStepDays := options.RiseSetStepDays
|
||
if riseSetStepDays <= 0 || math.IsNaN(riseSetStepDays) || math.IsInf(riseSetStepDays, 0) {
|
||
riseSetStepDays = solarEclipseRiseSetDefaultStepDays
|
||
}
|
||
nonCentralRiseSetCurves, nonCentralRiseSetComplete = solver.riseSetCurvesWithStatus(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.GreatestEclipse,
|
||
riseSetStepDays,
|
||
)
|
||
var bandHorizon []SolarEclipsePathPoint
|
||
if result.Type == SolarEclipseTotal {
|
||
totalMagnitudeOneSegments = solver.magnitudeContourSegmentsWithSpacing(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
result.GreatestEclipse,
|
||
1,
|
||
options.StepDays,
|
||
false,
|
||
solarEclipseNonCentralTotalBandTargetSpacingKM,
|
||
)
|
||
footprintsResult.CentralBandSegments, bandHorizon = solver.nonCentralTotalBandPolygons(
|
||
totalMagnitudeOneSegments,
|
||
footprintsResult.U1,
|
||
footprintsResult.U4,
|
||
result.GreatestEclipse,
|
||
nonCentralRiseSetCurves,
|
||
)
|
||
}
|
||
if !solarEclipseNonCentralBandContainsFootprints(
|
||
footprintsResult.CentralBandSegments, footprintsResult.CentralBandFootprints,
|
||
) {
|
||
footprintsResult.CentralBandSegments = nil
|
||
bandHorizon = nil
|
||
}
|
||
centralDuration := footprintsResult.U4.JDE - footprintsResult.U1.JDE
|
||
if len(footprintsResult.CentralBandSegments) == 0 &&
|
||
centralDuration <= solarEclipseNonCentralBandPreciseMaxDurationDays {
|
||
sweep, sweepHorizon, sampled := solver.centralBandSweepPolygons(
|
||
footprintsResult.U1.JDE,
|
||
footprintsResult.U4.JDE,
|
||
result.GreatestEclipse,
|
||
nonCentralRiseSetCurves,
|
||
)
|
||
if centralBandSweepCoversFootprints(
|
||
sweep, footprintsResult.CentralBandFootprints, sampled,
|
||
) {
|
||
footprintsResult.CentralBandSegments, bandHorizon = sweep, sweepHorizon
|
||
}
|
||
}
|
||
if !centralBandSweepCoversFootprints(
|
||
footprintsResult.CentralBandSegments, footprintsResult.CentralBandFootprints, false,
|
||
) {
|
||
footprintsResult.CentralBandSegments = nil
|
||
bandHorizon = nil
|
||
}
|
||
alignNonCentralBandHorizon(nonCentralRiseSetCurves, bandHorizon)
|
||
}
|
||
return totalMagnitudeOneSegments, nonCentralRiseSetCurves, nonCentralRiseSetComplete
|
||
}
|
||
|
||
// centralBandRiseSetCurves 求解中心带闭合需要的升落曲线；DisableRiseSetCurves 只影响是否
|
||
// 对外返回，两限中心食与非中心全食的端帽闭合始终需要它们。
|
||
func (solver solarEclipseSolver) centralBandRiseSetCurves(
|
||
result SolarEclipseResult,
|
||
options SolarEclipsePartialFootprintOptions,
|
||
nonCentralRiseSetCurves []SolarEclipseRiseSetCurve,
|
||
nonCentralRiseSetComplete bool,
|
||
) ([]SolarEclipseRiseSetCurve, bool) {
|
||
needRiseSetInternals := !options.DisableRiseSetCurves
|
||
if result.Centrality == SolarEclipseCentralTwoLimits && result.Type != SolarEclipsePartial {
|
||
needRiseSetInternals = true
|
||
}
|
||
if result.Centrality == SolarEclipseNonCentral && result.Type == SolarEclipseTotal {
|
||
needRiseSetInternals = true
|
||
}
|
||
if !needRiseSetInternals {
|
||
return nil, true
|
||
}
|
||
var riseSetCurves []SolarEclipseRiseSetCurve
|
||
riseSetComplete := true
|
||
if len(nonCentralRiseSetCurves) > 0 {
|
||
riseSetCurves, riseSetComplete = nonCentralRiseSetCurves, nonCentralRiseSetComplete
|
||
} else {
|
||
riseSetStepDays := options.RiseSetStepDays
|
||
if riseSetStepDays <= 0 || math.IsNaN(riseSetStepDays) || math.IsInf(riseSetStepDays, 0) {
|
||
riseSetStepDays = solarEclipseRiseSetDefaultStepDays
|
||
}
|
||
riseSetCurves, riseSetComplete = solver.riseSetCurvesWithStatus(
|
||
result.PartialBeginOnEarth,
|
||
result.PartialEndOnEarth,
|
||
result.GreatestEclipse,
|
||
riseSetStepDays,
|
||
)
|
||
}
|
||
if result.HasCentral {
|
||
solver.attachCentralAxisContactsToRiseSetCurves(
|
||
riseSetCurves,
|
||
result.CentralBeginOnEarth,
|
||
result.CentralEndOnEarth,
|
||
)
|
||
}
|
||
return riseSetCurves, riseSetComplete
|
||
}
|
||
|
||
// attachCentralBandClosureEnvelope 用两端的地平闭合弧构造解析中心带；没有得到完整的两条
|
||
// 闭合弧时不改动结果，交给采样兜底。
|
||
func (solver solarEclipseSolver) attachCentralBandClosureEnvelope(
|
||
result SolarEclipseResult,
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
riseSetCurves []SolarEclipseRiseSetCurve,
|
||
totalMagnitudeOneSegments [][]SolarEclipsePathPoint,
|
||
) {
|
||
var totalEnvelopeSegments [][]SolarEclipsePathPoint
|
||
if (result.Type == SolarEclipseAnnular || result.Type == SolarEclipseTotal || result.Type == SolarEclipseHybrid) &&
|
||
result.Centrality == SolarEclipseCentralTwoLimits &&
|
||
(len(riseSetCurves) > 0 || result.Type == SolarEclipseTotal) {
|
||
closures := make([][]SolarEclipsePathPoint, 0, 2)
|
||
for _, side := range solarEclipseCentralBandClosureSides(*footprintsResult, result) {
|
||
closure, ok := solver.centralBandHorizonClosureForSide(
|
||
result, *footprintsResult, riseSetCurves, totalMagnitudeOneSegments, side,
|
||
)
|
||
if !ok {
|
||
return
|
||
}
|
||
closures = append(closures, closure)
|
||
}
|
||
if len(closures) == 2 {
|
||
footprintsResult.CentralBandHorizonClosures = closures
|
||
solver.alignSolarEclipseCentralBandHorizonClosures(
|
||
riseSetCurves,
|
||
footprintsResult.CentralBandHorizonClosures,
|
||
)
|
||
if result.Type == SolarEclipseAnnular {
|
||
// The continuous critical envelope is the authoritative static
|
||
// central band. Instantaneous low-altitude footprint edges are
|
||
// open slices and must not veto this closed envelope: requiring
|
||
// every sampled slice to lie inside it recreates the comb-shaped
|
||
// union that this path replaces.
|
||
footprintsResult.CentralBandSegments = solver.centralTwoLimitBandEnvelope(
|
||
closures, result.GreatestEclipse,
|
||
)
|
||
if len(footprintsResult.CentralBandSegments) == 0 {
|
||
// At an extremely shallow polar annular event the analytic
|
||
// continuation can start exactly on the horizon and have no
|
||
// numerically visible first step. The sampled central sweep
|
||
// still carries the same contact and horizon topology.
|
||
solver.attachCentralBandSweep(
|
||
footprintsResult,
|
||
footprintsResult.U1.JDE, footprintsResult.U4.JDE,
|
||
result.GreatestEclipse, riseSetCurves,
|
||
)
|
||
}
|
||
} else if result.Type == SolarEclipseHybrid {
|
||
footprintsResult.CentralBandSegments = solver.hybridCentralBandEnvelope(closures, result)
|
||
} else {
|
||
// Share the signed physical branches with magnitude-one output;
|
||
// independently traced scalar contours may stop before the horizon.
|
||
// Keep the exact magnitude-one contours when they form a valid
|
||
// closed band. Only replace a scalar branch when its own sampled
|
||
// shadow slices prove that it terminates early or misses the band.
|
||
totalEnvelopeSegments = totalMagnitudeOneSegments
|
||
if len(solarEclipseTotalBandEnvelope(totalEnvelopeSegments, closures)) == 0 {
|
||
// Rebuild the closures from the same signed roots as the
|
||
// vector branches. Scalar magnitude contours may have valid
|
||
// samples but terminate on different horizon branches.
|
||
vectorClosures := make([][]SolarEclipsePathPoint, 0, 2)
|
||
for _, side := range []struct {
|
||
axis, first, last, direction float64
|
||
}{
|
||
{result.CentralBeginOnEarth, footprintsResult.U1.JDE, footprintsResult.U2.JDE, 1},
|
||
{result.CentralEndOnEarth, footprintsResult.U4.JDE, footprintsResult.U3.JDE, -1},
|
||
} {
|
||
first, last, rootsOK := solver.centralBandVectorHorizonRoots(side.axis, side.direction, side.first, side.last)
|
||
if !rootsOK {
|
||
vectorClosures = nil
|
||
break
|
||
}
|
||
_, key, classified := solver.magnitudeEvaluationAt(first.JDE).classify(first.Longitude, first.Latitude, true)
|
||
if !classified {
|
||
vectorClosures = nil
|
||
break
|
||
}
|
||
vectorClosures = append(vectorClosures, solver.centralBandHorizonClosure(first, last, key.direction, riseSetCurves))
|
||
}
|
||
if len(vectorClosures) == 2 {
|
||
closures = vectorClosures
|
||
footprintsResult.CentralBandHorizonClosures = closures
|
||
totalEnvelopeSegments = solver.centralBandVectorBranches(closures, result.GreatestEclipse)
|
||
}
|
||
}
|
||
footprintsResult.CentralBandSegments = solarEclipseTotalBandEnvelope(totalEnvelopeSegments, closures)
|
||
if len(footprintsResult.CentralBandSegments) == 0 && len(riseSetCurves) > 0 {
|
||
// Very shallow polar totalities may expose only one horizon
|
||
// endpoint on each magnitude-one branch. The analytic join then
|
||
// has no distinct start/end caps; use the sampled central sweep
|
||
// as a topology-preserving fallback.
|
||
solver.attachCentralBandSweep(
|
||
footprintsResult,
|
||
footprintsResult.U1.JDE, footprintsResult.U4.JDE,
|
||
result.GreatestEclipse, riseSetCurves,
|
||
)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
// attachCentralBandSweep 用扫掠兜底填充分段：解析扫掠与采样并集都可能返回，采样标记
|
||
// 必须跟着返回值走，否则导出层会把采样并集当成精确解析包络处理。
|
||
func (solver solarEclipseSolver) attachCentralBandSweep(
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
startJDE, endJDE, greatestJDE float64,
|
||
riseSetCurves []SolarEclipseRiseSetCurve,
|
||
) {
|
||
segments, _, sampled := solver.centralBandSweepPolygons(startJDE, endJDE, greatestJDE, riseSetCurves)
|
||
footprintsResult.CentralBandSegments = segments
|
||
footprintsResult.CentralBandSampled = sampled
|
||
}
|
||
|
||
// attachCentralBandFallbackSweep 是解析包络完全缺席时的最后兜底：只要采样重建覆盖了瞬时足迹
|
||
// 就采用它，并如实标记这是采样包络。
|
||
func (solver solarEclipseSolver) attachCentralBandFallbackSweep(
|
||
result SolarEclipseResult,
|
||
footprintsResult *SolarEclipsePartialFootprintsResult,
|
||
riseSetCurves []SolarEclipseRiseSetCurve,
|
||
) {
|
||
centrality := footprintsResult.Eclipse.Centrality
|
||
if len(footprintsResult.CentralBandSegments) == 0 && len(riseSetCurves) > 0 &&
|
||
footprintsResult.U1.JDE != 0 && footprintsResult.U4.JDE != 0 &&
|
||
(centrality == SolarEclipseCentralTwoLimits ||
|
||
centrality == SolarEclipseCentralOneLimit && result.Type == SolarEclipseAnnular) {
|
||
sweep, _, sweepSampled, covers := solver.centralBandBestSweep(
|
||
footprintsResult.U1.JDE, footprintsResult.U4.JDE,
|
||
result.GreatestEclipse, riseSetCurves,
|
||
footprintsResult.CentralBandFootprints,
|
||
)
|
||
if covers {
|
||
footprintsResult.CentralBandSegments = sweep
|
||
footprintsResult.CentralBandSampled = sweepSampled
|
||
}
|
||
}
|
||
}
|
||
|
||
type solarEclipseCentralBandClosureSide struct {
|
||
axisContactJDE float64
|
||
shadowContactJDE float64
|
||
innerContactJDE float64
|
||
direction float64
|
||
}
|
||
|
||
func solarEclipseCentralBandClosureSides(
|
||
footprints SolarEclipsePartialFootprintsResult,
|
||
result SolarEclipseResult,
|
||
) []solarEclipseCentralBandClosureSide {
|
||
innerStartJDE := result.CentralBeginOnEarth
|
||
if footprints.U2.JDE != 0 {
|
||
innerStartJDE = footprints.U2.JDE
|
||
}
|
||
innerEndJDE := result.CentralEndOnEarth
|
||
if footprints.U3.JDE != 0 {
|
||
innerEndJDE = footprints.U3.JDE
|
||
}
|
||
return []solarEclipseCentralBandClosureSide{
|
||
{result.CentralBeginOnEarth, footprints.U1.JDE, innerStartJDE, 1},
|
||
{result.CentralEndOnEarth, footprints.U4.JDE, innerEndJDE, -1},
|
||
}
|
||
}
|
||
|
||
// centralBandHorizonClosureForSide 解出中心带一端的地平闭合弧；三种食型各有一条取根链，
|
||
// 取不到唯一一对根就放弃该端（整条解析包络随之放弃）。
|
||
func (solver solarEclipseSolver) centralBandHorizonClosureForSide(
|
||
result SolarEclipseResult,
|
||
footprintsResult SolarEclipsePartialFootprintsResult,
|
||
riseSetCurves []SolarEclipseRiseSetCurve,
|
||
totalMagnitudeOneSegments [][]SolarEclipsePathPoint,
|
||
side solarEclipseCentralBandClosureSide,
|
||
) ([]SolarEclipsePathPoint, bool) {
|
||
var firstRoot, lastRoot SolarEclipsePathPoint
|
||
var ok bool
|
||
seededDirection := RiseSetDirection("")
|
||
if result.Type == SolarEclipseTotal {
|
||
firstRoot, lastRoot, ok = magnitudeOneHorizonRoots(totalMagnitudeOneSegments, side.direction)
|
||
if !ok {
|
||
firstRoot, lastRoot, ok = solver.centralBandVectorHorizonRoots(
|
||
side.axisContactJDE, side.direction, side.shadowContactJDE, side.innerContactJDE,
|
||
)
|
||
}
|
||
} else if result.Type == SolarEclipseHybrid {
|
||
firstRoot, lastRoot, ok = solver.centralBandVectorHorizonRoots(
|
||
side.axisContactJDE, side.direction, side.shadowContactJDE, side.innerContactJDE,
|
||
)
|
||
} else {
|
||
// A grazing closure arc routinely splits its two endpoints
|
||
// between the seeding paths: one sits outside the sampled
|
||
// horizon branches, the other outside the axis-adjacent Newton
|
||
// basin. Collect what every solver can offer and accept the pair
|
||
// only when exactly two distinct roots come out.
|
||
candidates := make([]SolarEclipsePathPoint, 0, 4)
|
||
directions := make([]RiseSetDirection, 0, 4)
|
||
curveDirection := RiseSetDirection("")
|
||
unionDirection := RiseSetDirection("")
|
||
appendRoots := func(
|
||
first, last SolarEclipsePathPoint,
|
||
direction RiseSetDirection,
|
||
found bool,
|
||
) {
|
||
if !found {
|
||
return
|
||
}
|
||
for _, root := range []SolarEclipsePathPoint{first, last} {
|
||
if root.JDE == 0 || solarEclipseRiseSetPointExists(candidates, root) {
|
||
continue
|
||
}
|
||
candidates = append(candidates, root)
|
||
directions = append(directions, direction)
|
||
}
|
||
}
|
||
firstRoot, lastRoot, ok = solver.centralLimitHorizonRootsNearAxisContact(
|
||
side.axisContactJDE, side.shadowContactJDE, side.innerContactJDE, side.direction,
|
||
)
|
||
appendRoots(firstRoot, lastRoot, "", ok)
|
||
curveRoots, curveDirection := solver.centralLimitHorizonRootsFromCurves(
|
||
riseSetCurves, side.shadowContactJDE, side.innerContactJDE,
|
||
)
|
||
for _, root := range curveRoots {
|
||
appendRoots(root, SolarEclipsePathPoint{}, curveDirection, true)
|
||
}
|
||
if len(candidates) < 2 {
|
||
// The sampled sweep is the most expensive seeding, so it
|
||
// only runs while the pair is still incomplete. Some grazing
|
||
// events have no two-root closure at all, and then the
|
||
// sampled band is the right representation rather than a
|
||
// fallback: 4862-09-28 ends 40 km inside the horizon (the
|
||
// cap is bounded by the umbral rim), and 1552-07-21 has its
|
||
// boundary running along the horizon (measured +0.004 then
|
||
// -0.000 degrees), so its closure arc is degenerate.
|
||
unionRoots, unionDirection := solver.centralLimitHorizonRootsFromSampledBoundary(
|
||
side.shadowContactJDE, side.innerContactJDE, result.GreatestEclipse,
|
||
footprintsResult.CentralBandFootprints, riseSetCurves,
|
||
)
|
||
for _, root := range unionRoots {
|
||
appendRoots(root, SolarEclipsePathPoint{}, unionDirection, true)
|
||
}
|
||
}
|
||
if seededDirection == "" {
|
||
seededDirection = curveDirection
|
||
}
|
||
if seededDirection == "" {
|
||
seededDirection = unionDirection
|
||
}
|
||
ok = len(candidates) == 2
|
||
if ok {
|
||
sort.Slice(candidates, func(first, second int) bool {
|
||
return candidates[first].JDE < candidates[second].JDE
|
||
})
|
||
firstRoot, lastRoot = candidates[0], candidates[1]
|
||
for _, direction := range directions {
|
||
if direction != "" {
|
||
seededDirection = direction
|
||
break
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if !ok {
|
||
return nil, false
|
||
}
|
||
// Near a pole, the first and last contacts can both be sunrise or
|
||
// both sunset. Classify the solved root instead of the temporal end.
|
||
_, key, classified := solver.magnitudeEvaluationAt(firstRoot.JDE).classify(
|
||
firstRoot.Longitude, firstRoot.Latitude, true,
|
||
)
|
||
if !classified && seededDirection == "" {
|
||
seededDirection = solarEclipseNearestGreatestDirection(riseSetCurves, firstRoot)
|
||
}
|
||
if !classified && seededDirection != "" {
|
||
// The local classification needs the eclipse to be exactly at
|
||
// its greatest there, which a shallow polar closure root does
|
||
// not always satisfy. The horizon curve that seeded the root
|
||
// already knows whether the Sun is rising or setting.
|
||
key = solarEclipseRiseSetCurveKey{
|
||
phase: RiseSetPhaseGreatest, direction: seededDirection,
|
||
}
|
||
}
|
||
if !classified {
|
||
return nil, false
|
||
}
|
||
return solver.centralBandHorizonClosure(
|
||
firstRoot, lastRoot, key.direction, riseSetCurves,
|
||
), true
|
||
}
|
||
|
||
// centralBandBestSweep returns the sweep candidate that contains the sampled
|
||
// umbra. The analytic sweep is smooth and stays the first choice whenever it
|
||
// really contains it; a grazing path whose envelope terminates early is rebuilt
|
||
// from the sampled footprints instead.
|
||
// The returned flag reports whether the candidate already passed the coverage
|
||
// audit, so the caller does not repeat the probe.
|
||
func (solver solarEclipseSolver) centralBandBestSweep(
|
||
startJDE, endJDE, greatestJDE float64,
|
||
riseSetCurves []SolarEclipseRiseSetCurve,
|
||
footprints []SolarEclipsePartialFootprint,
|
||
) ([][]SolarEclipsePathPoint, []SolarEclipsePathPoint, bool, bool) {
|
||
candidate, horizon, sampled := solver.centralBandSweepPolygonsReusing(
|
||
startJDE, endJDE, greatestJDE, riseSetCurves, footprints,
|
||
)
|
||
if solarEclipseBandContainsSampledFootprintsWithinKM(
|
||
candidate, footprints, centralBandSweepToleranceKM(sampled),
|
||
) {
|
||
return candidate, horizon, sampled, true
|
||
}
|
||
// The sampled reconstruction is only worth building when the sweep had an
|
||
// analytic region to reject; when the sweep itself already fell back to the
|
||
// sampled union, the audit above has judged that exact reconstruction.
|
||
if !sampled {
|
||
union := solver.centralBandSampledFootprintUnionOverRange(startJDE, endJDE, greatestJDE, footprints)
|
||
if len(union) > 0 && solarEclipseBandContainsSampledFootprintsWithinKM(
|
||
union, footprints, centralBandSweepToleranceKM(true),
|
||
) {
|
||
return union, nil, true, true
|
||
}
|
||
}
|
||
return candidate, horizon, sampled, false
|
||
}
|
||
|
||
// centralBandSweepToleranceKM returns the coverage bound of a sweep candidate.
|
||
func centralBandSweepToleranceKM(sampled bool) float64 {
|
||
if sampled {
|
||
return solarEclipseCentralBandUnionContainmentToleranceKM
|
||
}
|
||
return solarEclipseNonCentralBandContainmentToleranceKM
|
||
}
|
||
|
||
// centralBandSweepCoversFootprints validates a sweep candidate. The analytic
|
||
// sweep must contain every sampled footprint within the usual footprint
|
||
// tolerance; the sampled footprint union is decimated for tractability and is
|
||
// validated against the wider union bound instead.
|
||
func centralBandSweepCoversFootprints(
|
||
segments [][]SolarEclipsePathPoint,
|
||
footprints []SolarEclipsePartialFootprint,
|
||
sampled bool,
|
||
) bool {
|
||
tolerance := solarEclipseNonCentralBandContainmentToleranceKM
|
||
if sampled {
|
||
tolerance = solarEclipseCentralBandUnionContainmentToleranceKM
|
||
}
|
||
return solarEclipseBandContainsFootprintsWithinKM(segments, footprints, tolerance)
|
||
}
|
||
|
||
// setCenterLinePairWidths replaces the analytic 2r/sin(altitude) width with the
|
||
// distance between the paired limits, which is the width the tables publish.
|
||
// The analytic form is a small-angle approximation that diverges towards the
|
||
// horizon (2017-08-21 reports 10,062 km near its ends instead of ~90 km), so it
|
||
// is only kept as the greatest-eclipse figure that the catalogues quote. A
|
||
// sample whose cross-section does not close has no width at all, and a one-limit
|
||
// event has none anywhere - which is why catalogues print no width for it (NASA
|
||
// lists 1874-10-10 with "-").
|
||
func (solver solarEclipseSolver) setCenterLinePairWidths(
|
||
centerLine []SolarEclipsePathPoint,
|
||
centrality SolarEclipseCentrality,
|
||
northern, southern []SolarEclipsePathPoint,
|
||
paired []bool,
|
||
) {
|
||
if len(centerLine) == 0 {
|
||
return
|
||
}
|
||
if centrality != SolarEclipseCentralTwoLimits {
|
||
for index := range centerLine {
|
||
centerLine[index].WidthKM = 0
|
||
}
|
||
return
|
||
}
|
||
if len(northern) != len(centerLine) || len(southern) != len(centerLine) || len(paired) != len(centerLine) {
|
||
return
|
||
}
|
||
for index := range centerLine {
|
||
if !paired[index] {
|
||
centerLine[index].WidthKM = 0
|
||
continue
|
||
}
|
||
width := solarEclipsePathDistanceKM(northern[index], southern[index])
|
||
if width <= 0 || width > solarEclipsePathMaxPossibleWidthKM {
|
||
// A cross-section wider than the Earth cannot be a footprint edge.
|
||
width = 0
|
||
}
|
||
centerLine[index].WidthKM = width
|
||
}
|
||
}
|
||
|
||
// centralPathMaxCentralDuration returns the longest central phase on the center
|
||
// line and where it happens. The local solution reuses the event-local
|
||
// interpolated ephemeris, which is what keeps a per-sample scan affordable.
|
||
// Catalogues publish the duration at greatest eclipse,
|
||
// which for a shallow event is not the longest one: 2020-06-21 lasts 38 s there
|
||
// but 1m22s near the sunrise end of its track. Samples below the horizon are
|
||
// skipped because the central phase is not observable from them; the width is
|
||
// deliberately not used as a filter, because a one-limit event has no width at
|
||
// all yet still has a published duration.
|
||
func (solver solarEclipseSolver) centralPathMaxCentralDuration(
|
||
centerLine []SolarEclipsePathPoint,
|
||
) (float64, float64, float64) {
|
||
bestDays, bestLongitude, bestLatitude := 0.0, 0.0, 0.0
|
||
for _, point := range centerLine {
|
||
if point.SunAltitude < -solarEclipsePathDurationHorizonToleranceDegrees {
|
||
continue
|
||
}
|
||
span := solver.centralPhaseDurationDaysAt(point.JDE, point.Longitude, point.Latitude)
|
||
if span <= 0 {
|
||
continue
|
||
}
|
||
if span > bestDays {
|
||
bestDays, bestLongitude, bestLatitude = span, point.Longitude, point.Latitude
|
||
}
|
||
}
|
||
return bestDays, bestLongitude, bestLatitude
|
||
}
|
||
|
||
func (solver solarEclipseSolver) attachCentralAxisContactPoints(
|
||
points []SolarEclipsePathPoint,
|
||
startJDE, endJDE float64,
|
||
) []SolarEclipsePathPoint {
|
||
if len(points) == 0 {
|
||
return points
|
||
}
|
||
const supportOffsetDays = 0.1 / 86400.0
|
||
contacts := make([]SolarEclipsePathPoint, 0, 2)
|
||
for _, jd := range []float64{startJDE, endJDE} {
|
||
if point, ok := solver.centralAxisContactPointAt(jd); ok {
|
||
contacts = append(contacts, point)
|
||
}
|
||
}
|
||
if len(contacts) != 2 {
|
||
return points
|
||
}
|
||
supports := make([]SolarEclipsePathPoint, 0, 2)
|
||
if endJDE-startJDE > 2*supportOffsetDays {
|
||
if point, ok := solver.centralPathPointAt(startJDE + supportOffsetDays); ok {
|
||
supports = append(supports, point)
|
||
}
|
||
if point, ok := solver.centralPathPointAt(endJDE - supportOffsetDays); ok {
|
||
supports = append(supports, point)
|
||
}
|
||
}
|
||
filtered := points[:0]
|
||
for _, point := range points {
|
||
if math.Abs(point.JDE-startJDE) <= solarEclipsePathDuplicateTimeDays ||
|
||
math.Abs(point.JDE-endJDE) <= solarEclipsePathDuplicateTimeDays {
|
||
continue
|
||
}
|
||
filtered = append(filtered, point)
|
||
}
|
||
points = append(filtered, supports...)
|
||
points = append(points, contacts...)
|
||
sort.Slice(points, func(first, second int) bool { return points[first].JDE < points[second].JDE })
|
||
return normalizeSolarEclipsePathPointSeries(points)
|
||
}
|
||
|
||
func setSolarEclipseCentralContactWidths(
|
||
centerLine, northern, southern []SolarEclipsePathPoint,
|
||
) {
|
||
if len(centerLine) < 2 || len(northern) != len(southern) {
|
||
return
|
||
}
|
||
for _, centerIndex := range []int{0, len(centerLine) - 1} {
|
||
bestIndex := -1
|
||
bestDelta := math.Inf(1)
|
||
for index := range northern {
|
||
delta := math.Abs(northern[index].JDE - centerLine[centerIndex].JDE)
|
||
if delta < bestDelta {
|
||
bestIndex, bestDelta = index, delta
|
||
}
|
||
}
|
||
if bestIndex >= 0 && bestDelta <= 0.2/86400.0 {
|
||
centerLine[centerIndex].WidthKM = solarEclipsePathDistanceKM(
|
||
northern[bestIndex], southern[bestIndex],
|
||
)
|
||
}
|
||
}
|
||
}
|
||
|
||
func (solver solarEclipseSolver) attachCentralAxisContactsToRiseSetCurves(
|
||
curves []SolarEclipseRiseSetCurve,
|
||
startJDE, endJDE float64,
|
||
) {
|
||
for _, endpoint := range []struct {
|
||
jde float64
|
||
direction RiseSetDirection
|
||
}{
|
||
{startJDE, RiseSetDirectionRise},
|
||
{endJDE, RiseSetDirectionSet},
|
||
} {
|
||
contact, ok := solver.centralAxisContactPointAt(endpoint.jde)
|
||
if !ok {
|
||
continue
|
||
}
|
||
insertSolarEclipseRiseSetContact(curves, contact, endpoint.direction)
|
||
}
|
||
}
|
||
|
||
func insertSolarEclipseRiseSetContact(
|
||
curves []SolarEclipseRiseSetCurve,
|
||
contact SolarEclipsePathPoint,
|
||
direction RiseSetDirection,
|
||
) {
|
||
bestCurve, bestSegment, bestPoint := -1, -1, -1
|
||
bestDistance := math.Inf(1)
|
||
for curveIndex := range curves {
|
||
curve := &curves[curveIndex]
|
||
if curve.Phase != RiseSetPhaseGreatest || curve.Direction != direction {
|
||
continue
|
||
}
|
||
for segmentIndex, segment := range curve.Segments {
|
||
if len(segment) < 2 ||
|
||
contact.JDE < segment[0].JDE-solarEclipseRiseSetTimeEpsilonDays ||
|
||
contact.JDE > segment[len(segment)-1].JDE+solarEclipseRiseSetTimeEpsilonDays {
|
||
continue
|
||
}
|
||
pointIndex := sort.Search(len(segment), func(index int) bool {
|
||
return segment[index].JDE >= contact.JDE
|
||
})
|
||
if pointIndex == 0 {
|
||
pointIndex = 1
|
||
} else if pointIndex >= len(segment) {
|
||
pointIndex = len(segment) - 1
|
||
}
|
||
first, second := segment[pointIndex-1], segment[pointIndex]
|
||
fraction := 0.0
|
||
if second.JDE > first.JDE {
|
||
fraction = (contact.JDE - first.JDE) / (second.JDE - first.JDE)
|
||
}
|
||
fraction = math.Max(0, math.Min(1, fraction))
|
||
candidate := solarEclipsePathSphericalInterpolate(first, second, fraction)
|
||
distance := solarEclipsePathDistanceKM(candidate, contact)
|
||
if distance < bestDistance {
|
||
bestCurve, bestSegment, bestPoint = curveIndex, segmentIndex, pointIndex
|
||
bestDistance = distance
|
||
}
|
||
}
|
||
}
|
||
if bestCurve < 0 || bestDistance > solarEclipseRiseSetTargetSpacingKM {
|
||
return
|
||
}
|
||
segment := curves[bestCurve].Segments[bestSegment]
|
||
if bestPoint > 0 && math.Abs(segment[bestPoint-1].JDE-contact.JDE) <= solarEclipseRiseSetTimeEpsilonDays {
|
||
segment[bestPoint-1] = contact
|
||
} else if bestPoint < len(segment) && math.Abs(segment[bestPoint].JDE-contact.JDE) <= solarEclipseRiseSetTimeEpsilonDays {
|
||
segment[bestPoint] = contact
|
||
} else {
|
||
segment = append(segment, SolarEclipsePathPoint{})
|
||
copy(segment[bestPoint+1:], segment[bestPoint:])
|
||
segment[bestPoint] = contact
|
||
}
|
||
curves[bestCurve].Segments[bestSegment] = segment
|
||
}
|
||
|
||
func (solver solarEclipseSolver) centralBandFootprintsWithStep(
|
||
outerStartJDE, innerStartJDE, innerEndJDE, outerEndJDE, greatestJDE, stepDays float64,
|
||
) ([]SolarEclipsePartialFootprint, float64) {
|
||
if stepDays <= 0 || math.IsNaN(stepDays) || math.IsInf(stepDays, 0) {
|
||
stepDays = solarEclipseCentralBandStepDays
|
||
}
|
||
if innerStartJDE != 0 && innerEndJDE != 0 &&
|
||
outerStartJDE < innerStartJDE && innerStartJDE < innerEndJDE && innerEndJDE < outerEndJDE {
|
||
start, actualStartStep, _ := solver.shadowFootprintsWithSpacing(
|
||
outerStartJDE, innerStartJDE, innerStartJDE, stepDays,
|
||
solarEclipseCentralBandBoundaryPoints, solarEclipseCentralShadow,
|
||
solarEclipseCentralBandTargetSpacingKM,
|
||
)
|
||
end, actualEndStep, _ := solver.shadowFootprintsWithSpacing(
|
||
innerEndJDE, outerEndJDE, innerEndJDE, stepDays,
|
||
solarEclipseCentralBandBoundaryPoints, solarEclipseCentralShadow,
|
||
solarEclipseCentralBandTargetSpacingKM,
|
||
)
|
||
return append(start, end...), math.Max(actualStartStep, actualEndStep)
|
||
}
|
||
if greatestJDE <= outerStartJDE || greatestJDE >= outerEndJDE {
|
||
greatestJDE = (outerStartJDE + outerEndJDE) / 2
|
||
}
|
||
footprints, actualStep, _ := solver.shadowFootprintsWithSpacing(
|
||
outerStartJDE, outerEndJDE, greatestJDE, stepDays,
|
||
solarEclipseCentralBandBoundaryPoints, solarEclipseCentralShadow,
|
||
solarEclipseCentralBandTargetSpacingKM,
|
||
)
|
||
return footprints, actualStep
|
||
}
|