The section about MultiPolygons at https://geoarrow.org/format.html#memory-layouts mentions:
> The child name of the outer list should be “polygons”; the child name of the > middle list should be “rings”; the child name of the inner list should be > “vertices”. So this is currently phrased as a "should" and not "must" regarding the list's field names, and so the data generated by GDAL is valid under that description. It might be good to verify with other consumers that those indeed can handle such data (and add some test data with varying field names to test against). Joris On Mon, 7 Oct 2024 at 15:39, Even Rouault via gdal-dev <[email protected]> wrote: > > Michael, > > my understanding of https://geoarrow.org/format.html#memory-layouts is that > what writes OGR is supposed to be fine since they mentionned types like > 'List<List<FixedSizeList<double>[2]>>'. Perhaps I've missed something or > nanoarrow has stricter expectations? CC'ing Dewey Dunnington > > Even > > Le 07/10/2024 à 15:23, Michael Sumner via gdal-dev a écrit : > > I realize I left out the INTERLEAVING, ie. > > ogr2ogr ~/fromgdal.arrow > ogr/data/arrow/from_paleolimbot_geoarrow/polygon-default.ipc -lco > GEOMETRY_ENCODING=GEOARROW_INTERLEAVED > > but still, I get these list<item elements rather than their > rings/vertices/geoarrow.point type names: > > <nanoarrow_array_stream struct<row_num: int32, geometry: > geoarrow.polygon{list<item: list<item: fixed_size_list(2)<xy: double>>>}>> > > > > On Tue, Oct 8, 2024 at 12:19 AM Michael Sumner <[email protected]> wrote: >> >> When I investigate the schema in one of the test files >> >> ogr/data/arrow/from_paleolimbot_geoarrow/polygon-default.ipc >> >> I see expected list<polygons and list<rings and xy etc. I'm printing this >> by using R nanoarrow::read_arrow, or from poLayer->GetArrowStream and I get >> the same output: >> >> <nanoarrow_array_stream struct<row_num: int32, geometry: >> geoarrow.polygon{list<rings: list<vertices: >> geoarrow.point{fixed_size_list(2)<xy: double>}>>}>> >> >> If I write a new .arrow with GDAL >> >> ogr2ogr ~/fromgdal.arrow >> ogr/data/arrow/from_paleolimbot_geoarrow/polygon-default.ipc >> >> the stream schema looks like this: >> >> <nanoarrow_array_stream struct<row_num: int32, geometry: >> geoarrow.polygon{list<item: list<item: struct<x: double, y: double>>>}>> >> >> and from nanoarrow I see >> >> nanoarrow::read_nanoarrow("~/fromgdal.arrow") >> Error in read_nanoarrow.character("~/fromgdal.arrow") : >> array_stream->get_schema(): [29] Expected >= 1330795077 bytes of remaining >> data but found 2266 bytes in buffer >> >> Are we in-between moves regarding specifications, or something? I'm having >> good results generally and this seems like a problem in the Arrow driver for >> write. >> >> Cheers, Mike >> >> >> -- >> Michael Sumner >> Research Software Engineer >> Australian Antarctic Division >> Hobart, Australia >> e-mail: [email protected] > > > > -- > Michael Sumner > Research Software Engineer > Australian Antarctic Division > Hobart, Australia > e-mail: [email protected] > > _______________________________________________ > gdal-dev mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/gdal-dev > > -- > http://www.spatialys.com > My software is free, but my time generally not. > > _______________________________________________ > gdal-dev mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
