[R-sig-Geo] FYI - bug in GDAL 2.1.0: FID detection in GeoJSON results wrong feature count

[Andy Teucher]

There is a small known bug in GDAL 2.1.0 that I was bitten by when using
rgdal::readOGR to read in GeoJSON data.

The bug is with the GeoJSON format, where if you have multiple polygons
with the same "id" property, only one will be recognized (The actual bug is
more complex than that, but that was my circumstance).

The bug report is here: https://trac.osgeo.org/gdal/ticket/6538, and my
demonstration of it with rgdal is here:
https://gist.github.com/ateucher/59365353d61ab41bf7ae14905941eaab.

It looks like it has been fixed in GDAL 2.1.1. I tested it with GDAL 2.0.1
and the current development version (2.2.x) and the issue is not there, but
I think 2.1.0 is common on a lot of systems right now. So if you are
working with GeoJSON and have that GDAL version, keep your eye out for it.

Cheers,
Andy Teucher

	[[alternative HTML version deleted]]