[gdal-dev] writing arrow geometry

[Even Rouault]

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 <mdsumner at gmail.com> 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: mdsumner at gmail.com
>
>
>
> -- 
> Michael Sumner
> Research Software Engineer
> Australian Antarctic Division
> Hobart, Australia
> e-mail: mdsumner at gmail.com
>
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