ArcGIS Server JSON to GeoJSON does not always work

Question

I'm using GDAL 1.10.1 for reading ArcGIS Server responses with automatic conversion to GeoJSON format as described in Converting ArcGIS Server JSON to GeoJSON? post.

However, it looks like some of the Feature Servers published by ArcGIS return empty results when queried using the above technique: http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/LandusePlanning/FeatureServer/2/query?where=objectid+%3D+objectid&outfields=&f=pjson

Could someone explain why the technique is not working for some data?

Answer 1

The following special cases (at least) need to be considered when reading ArcGIS data using GDAL/OGR libraries:

1. GDAL/OGR cannot process GeoJSON results containing UNICODE characters (\uABCD style)
2. ArcGIS limits the amount of objects returned per single query (usually to 1000)
3. Empty feature sets are not accepted by GDAL/OGR

This means that special care needs to be taken by the application client code for GeoJSON output returned by ArcGIS before passing it over to GDAL/OGR. A solution could be to run ArcGIS queries without GDAL/OGR, save GeoJSON results into a file to be processed so that the contents are acceptable for GDAL/OGR.