[GEO] Optional exception for GeoPoints > 2 dimensions

[nknize]

Related to #10510 and #10539 the discussion involves adding an optional mapping parameter to throw an exception if an input GeoJSON contains coordinates with >2 dimensions.

The loosely defined GeoJSON spec (at http://geojson.org/geojson-spec.html#positions) states: "There must be at least two elements, and may be more." With no limit on how many elements can be in a coordinate. Since ES currently supports 2D only, it seems natural for default behavior to throw an exception if a coordinate is received with any more than 2 elements. There are a few "user-friendly" questions surrounding this (which have cropped up more than once on the issue list)

1. Should another validation parameter be added to optionally fail on coordinates > 2d?
2. Should it be part of the existing 'validate' parameter?
3. Should the default throw an exception for >2d coordinates forcing users to set the parameter to handle pre-existing geojson data?

[rjernst]

@nknize You could change the behavior of validate, but only run the additional check if the index was created with new versions of ES (1.6+?).

[nknize]

@rjernst I have outstanding pr #10248 that deprecates the "old" validate and normalize options. I can update the behavior there prior to merge /cc @colings86

[imotov]

Superseded by #22917. Closing.