48 lines
1.8 KiB
Go
48 lines
1.8 KiB
Go
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package basic
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import (
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"math"
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"testing"
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"time"
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)
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func TestMars20250729FiniteContactContoursRespectWebMercatorSpacing(t *testing.T) {
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zone := time.FixedZone("UTC+8", 8*60*60)
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start := time.Date(2025, time.July, 29, 0, 0, 0, 0, zone)
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paths, err := FindPlanetOccultationPaths(start, start.Add(24*time.Hour), OccultationMars, OccultationPathOptions{
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Step: 20 * time.Minute, TargetSpacingKM: 900, RiseSetStep: time.Minute,
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DisableFootprints: true, IncludeFootprintTimeline: true, FootprintTimelineStep: 5 * time.Minute,
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})
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if err != nil || len(paths) != 1 {
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t.Fatalf("FindPlanetOccultationPaths() paths=%d err=%v, want one", len(paths), err)
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}
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for _, item := range []struct {
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name string
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contours [][]OccultationPathPoint
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}{
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{name: "partial", contours: paths[0].PartialBandContours},
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{name: "total", contours: paths[0].TotalBandContours},
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} {
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for contourIndex, contour := range item.contours {
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for pointIndex := 1; pointIndex < len(contour); pointIndex++ {
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spacing := webMercatorGeoPointSpacingKM(contour[pointIndex-1], contour[pointIndex])
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if spacing > 45 {
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t.Fatalf("%s contour %d edge %d has %.1f km Web Mercator spacing, want <=45 km", item.name, contourIndex, pointIndex, spacing)
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}
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}
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}
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}
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}
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func webMercatorGeoPointSpacingKM(first, second OccultationPathPoint) float64 {
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const maxLatitude = 85.05112878
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const radiusKM = 6378.1366
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clamp := func(value float64) float64 { return math.Max(-maxLatitude, math.Min(maxLatitude, value)) }
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longitude := math.Remainder(second.Longitude-first.Longitude, 360) * math.Pi / 180
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firstLatitude := clamp(first.Latitude) * math.Pi / 180
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secondLatitude := clamp(second.Latitude) * math.Pi / 180
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firstY := math.Log(math.Tan(math.Pi/4 + firstLatitude/2))
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secondY := math.Log(math.Tan(math.Pi/4 + secondLatitude/2))
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return radiusKM * math.Hypot(longitude, secondY-firstY)
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}
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