Github user k255 commented on the issue:
https://github.com/apache/drill/pull/258
It's good that now there's commiter which is aware of the GIS context! The
list of functions added in this PR is as follows:
ST_Buffer, ST_Contains, ST_Crosses, ST_Difference, ST_Disjoint,
ST_DiST_ance, ST_Envelope, ST_Equals, ST_Intersects, ST_Overlaps, ST_Relate,
ST_Touches, ST_Transform, ST_Union, ST_UnionAggregate, ST_X, ST_Y, ST_XMin,
ST_XMax, ST_YMin, ST_YMax
Regarding the documentation, I wouldn't like to duplicate it because I
followed what is available in PostGIS (which actually uses GEOS lib, in similar
way as drill-gis uses relevant java libs - esri, proj4j) and these are defined
in open geospatial consortium (OGC) specs. Of course here we have just a subset
of what PostGIS is capable of, but I think it's valuable subset.
So i.e. for ST_X function the docs are at
http://www.postgis.net/docs/ST_X.html
Also on example usage please refer to examples contained in readme at:
https://github.com/k255/drill-gis
I'll also finally need to think about blog post/presentation on this
extension, but most probably not in following days but later in the future.
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