This is related to determining the interior of a Polygon.
My difficulty is that if I specify a Polygon covering the Earth going from East to West, it will still have a boundary along the antemeridian, which would show up in azimuthal projections. For example, in GeoJSON:
{
"type": "Polygon",
"coordinates": [
[[-180, -90], [-180, 90], [180, 90], [180, -90], [-180, -90]]
]
}
Is there a standard way to specify a whole-sphere Polygon, with no boundary?
I've thought about using an empty exterior ring:
{
"type": "Polygon",
"coordinates": [
[]
]
}
The logic being that I could specify further rings as holes to be punched into the whole-sphere Polygon.
Unfortunately, GeoJSON stipulates that LinearRings must have at least 4 points, so this would be straying from the specification. However, I'm still interested in understanding whether this approach is taken anywhere else.
Best Answer
Since there doesn't seem to be a standard way to represent this somewhat rare situation of a polygon with no boundary covering the whole Earth, we decided to add our own
{type: "Sphere"}
, which has worked remarkably well for our purposes.We decided not to use a Polygon containing an empty LinearRing, since this more intuitively represents an empty polygon and could easily lead to confusion and accidental creation of whole-Earth polygons.