Files
astro/eclipse/svg/lunar_map_polar_test.go
T
b612 2bf8478639 feat: 完善日月食与月掩几何链路并扩展历法接口
- 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
2026-09-17 12:27:40 +08:00

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package svg
import (
"testing"
"time"
"b612.me/astro/basic"
eclipsecore "b612.me/astro/eclipse"
"b612.me/astro/internal/svgmap"
)
// TestLunarEclipseMapSVGPolarWitnessStaysOutsideEquirectangularVisibility 固定全球月食地图在
// 极区的可见性契约。等距圆柱投影在高纬把经度拉伸:1° 的球面地平弧在极点附近可以横跨近
// 180° 经度,只连端点就会把地平线以外画进可见区。1904-09-24 的 P1 在南极点附近有一个
// 月心高度约 −0.05° 的见证点,曾经被画进 visible-at-p1 多边形。
// TestLunarEclipseMapSVGPolarWitnessStaysOutsideEquirectangularVisibility pins the polar
// visibility contract of the global lunar-eclipse map. Equirectangular projection stretches
// longitude near a pole: a 1-degree spherical horizon arc can span almost 180 degrees there, so
// joining endpoints alone paints sky below the horizon as visible. At P1 of 1904-09-24 a witness
// near the south pole sits about 0.05 degrees below the Moon's horizon and used to be painted
// inside the visible-at-p1 polygon.
func TestLunarEclipseMapSVGPolarWitnessStaysOutsideEquirectangularVisibility(t *testing.T) {
date := time.Date(1904, 9, 24, 0, 0, 0, 0, time.UTC)
info, ok := eclipsecore.LunarEclipseOnDate(date)
if !ok {
t.Fatal("missing lunar eclipse")
}
frame := eclipseMapFrame(lunarEclipseMapDefaultWidth, lunarEclipseMapDefaultHeight,
svgmap.ProjectionEquirectangular, 142, 92)
path, boundary := lunarEclipseVisibilityPath(info.PenumbralStart, frame)
if len(boundary) == 0 {
t.Fatal("visibility path has no boundary")
}
rings := svgClosedPathRings(t, `<path d="`+path+`"/>`)
if len(rings) == 0 {
t.Fatal("visibility path has no rings")
}
jd := basic.Date2JDE(info.PenumbralStart)
// 只取足够深入地平线以下的见证点:−89.9° 处月心高度约 −0.054°,而更靠近极点的
// −89.99° 只有约 −0.004°,落在可见性判定本身的数值容差里,不能作为回归依据。
// Only a witness clearly below the horizon is used: at -89.9 degrees the Moon centre sits
// about 0.054 degrees down, while -89.99 degrees is only about 0.004 degrees down and lies
// inside the numerical tolerance of the visibility test itself.
witnesses := []struct {
longitude float64
latitude float64
}{
{-115, -89.9},
}
for _, witness := range witnesses {
altitude := basic.HMoonHeight(jd, witness.longitude, witness.latitude, 0)
if altitude >= -0.01 {
// 见证点必须先确实是地平线以下,否则这个回归就失去意义。
t.Fatalf("witness (%g,%g) altitude=%g, want below the horizon",
witness.longitude, witness.latitude, altitude)
}
x, y, projectable := frame.Project(witness.longitude, witness.latitude)
if !projectable {
continue
}
inside := false
for _, ring := range rings {
inside = inside || pointInLunarVisibilityPolygon(x, y, ring)
}
if inside {
t.Fatalf("below-horizon witness (%g,%g) altitude=%g is painted inside the visible region",
witness.longitude, witness.latitude, altitude)
}
}
}