geometry.Poly{}.Valid() does check if the polygon is valid

[nico-bock]

Description

geometry.Poly{}.Valid() check only if the Exterior and the holes are valid Series, not if they are a valid polygon.

Therefore Polygons with missing Points, intersecting edges etc. are not detected.

Is this intended or just not necessary till now?

Exmaple:

package main

import (
	"github.com/tidwall/geojson"
	"github.com/tidwall/geojson/geometry"
)

func main() {
	polygon := geometry.NewPoly([]geometry.Point{
		{
			8.88242492198438,
			47.85972404073712,
		},
		{
			6.003023836249525,
			47.467582223811604,
		},
		{
			10.561998072355692,
			45.71873204889732,
		},
		{
			6.738413586888328,
			48.35187757503576,
		},
		{
			8.88242492198438,
			47.85972404073712,
		},
	}, nil, nil)

	print(polygon.Valid()) //Expected to be false

	geojsonPolygon := geojson.NewPolygon(polygon)
	print(geojsonPolygon.Valid()) //Expected to be false

	geojsonPolygonFeature := geojson.NewFeature(geojsonPolygon, "")
	print(geojsonPolygonFeature.Valid()) //Expected to be False

	geojsonPolygonFeatureJson := geojsonPolygonFeature.JSON()
	print(geojsonPolygonFeatureJson)

}

[tidwall]

A more robust Valid operation would be nice, but it's not something I've gotten around to.

[nico-bock]

If you want to, I could make a PR for this.