Detect and handle heterogenous coordinates

[tmcw]

GeoJSON that can exist:

{
  "type": "LineString",
  "coordinates": [[0, 1, 2], [2, 3]]
}

Should this be a LINESTRING or LINESTRING Z in WKT? Probably just a LINESTRING. This should be detected and handled explicitly.

[VladimirAlexiev]

According to https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry, the spec is https://portal.ogc.org/files/?artifact_id=25355. It has two "branch" grammars

• 7.2.2 BNF Productions for Two-Dimension Geometry WKT
• 7.2.3 BNF Productions for Three-Dimension Geometry WKT

And doesn't allow mixing of 2D and 3D coordinates. I think you have 2 options:

• add extra param whether the output should be 2D or 3D, and check the input strictly
• examine the input and drop Z if its presence is inconsistent