public String getGeoArrowType() {
      return (encoding != null && (encoding.contains("polygon") ||
        encoding.contains("point") ||
        encoding.contains("line"))) ? encoding : null;
    }
Returns the geoarrow type string of this geometry column, or null if not geoarrow.
planetiler-core/src/main/java/com/onthegomap/planetiler/reader/parquet/GeoParquetMetadata.java