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37 lines
1.9 KiB
Markdown
37 lines
1.9 KiB
Markdown
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# geodist
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GoLang package to compute the distance between two geographic latitude, longitude coordinates
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## Algorithm Comparison
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* `Vincenty` is more accurate than `Haversine` because is considers the Earth's [ellipticity](https://www.dictionary.com/browse/ellipticity) when performing the calculation, but takes a longer time to compute.
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* [Wikipedia: Haversine](https://en.wikipedia.org/wiki/Haversine_formula)
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* [Wikipedia: Vincenty](https://en.wikipedia.org/wiki/Vincenty%27s_formulae)
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* [Is the Haversine Formula or the Vincenty's Formula better for calculating distance?](https://stackoverflow.com/q/38248046/452281)
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## Example
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* [example.go](example/example.go)
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```go
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var newYork = geodist.Coord{Lat: 40.7128, Lon: 74.0060}
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var sanDiego = geodist.Coord{Lat: 32.7157, Lon: 117.1611}
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miles, km, ok := geodist.VincentyDistance(newYork, sanDiego)
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if !ok {
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fmt.Println("Unable to compute Vincenty Distance.")
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return
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}
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fmt.Printf(" [Vincenty] New York to San Diego: %.3f m, %.3f km\n", miles, km)
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var elPaso = geodist.Coord{Lat: 31.7619, Lon: 106.4850}
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var stLouis = geodist.Coord{Lat: 38.6270, Lon: 90.1994}
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miles, km = geodist.HaversineDistance(elPaso, stLouis)
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fmt.Printf("[Haversine] El Paso to St. Louis: %.3f m, %.3f km\n", miles, km)
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```
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## Online Calculators
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* **Great Circle**: [NOAA: Latitude/Longitude Distance Calculator](https://www.nhc.noaa.gov/gccalc.shtml)
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* **Haversine**: [Moveable Type: Calculate distance, bearing and more between Latitude/Longitude points](https://www.movable-type.co.uk/scripts/latlong.html)
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* **Vincenty**: [CQSRG: WGS-84 World Geodetic System Distance Calculator](https://www.cqsrg.org/tools/GCDistance/)
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## Acknowledgements
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* [Haversine Algorithm](https://gist.github.com/cdipaolo/d3f8db3848278b49db68) in `GoLang`
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* [Vincenty Algorithm](https://web.archive.org/web/20181109001358/http://www.5thandpenn.com/GeoMaps/GMapsExamples/distanceComplete2.html) in `JavaScript`
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