Projection of a GeoParquet file?

[nshiab]

Hello,

ST_Read_Meta() is great for finding the projection of common geospatial files, but I couldn't make it work with GeoParquet files.

How would you retrieve the projection of a GeoParquet file?

This is what I am using to write my GeoParquet files. Maybe there is way to add the projection as an option somehow and then retrieve it when loading the data?

COPY <my_table> TO '<my_output>.parquet' WITH (FORMAT PARQUET);

Thank you! 🙏

[Maxxen]

Hello! It's currently not possible to specify a projection when writing GeoParquet files. You can inspect the key-value metadata of an existing geoparquet file to extract any projection info manually using the parquet_kv_metadata function (in combination with the json extension to extract the "crs" property form the "geo" kv-metadata key).

[nshiab]

Understood. Thank you @Maxxen !