wgtmac commented on code in PR #240:
URL: https://github.com/apache/parquet-format/pull/240#discussion_r1616485093
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src/main/thrift/parquet.thrift:
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@@ -373,6 +408,74 @@ struct JsonType {
struct BsonType {
}
+/**
+ * Phyiscal type and encoding for the geometry type.
+ */
+enum GeometryEncoding {
+ /**
+ * Allowed for phyiscal type: BYTE_ARRAY.
+ *
+ * Well-known binary (WKB) representations of geometries. It supports 2D or
+ * 3D geometries of the standard geometry types (Point, LineString, Polygon,
+ * MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection). This
+ * is the preferred option for maximum portability.
+ *
+ * This encoding enables GeometryStatistics to be set in the column chunk
+ * and page index.
+ */
+ WKB = 0;
+
+ /**
+ * Encodings from POINT to MULTIPOLYGON below are specialized for single
+ * geometry type and inspired by GeoArrow (https://geoarrow.org/format.html)
+ * native encodings. It uses the separated (struct) representation of
+ * coordinates for single-geometry type encodings because this encoding
+ * results in useful column statistics when row groups and/or files contain
+ * related features.
+ *
+ * WARNING: GeometryStatistics cannot be enabled for these encodings because
+ * only leaf columns can have column statistics and page index.
+ *
+ * The actual coordinates of the geometries MUST be stored as native numbers,
+ * i.e. using the DOUBLE type in a (repeated) group of fields (exact
+ * repetition depending on the geometry type).
+ *
+ * For the POINT encoding, this results in a struct of two fields for x and y
+ * coordinates (in case of 2D geometries):
+ * optional group geometry {
+ * required double x;
+ * required double y;
+ * }
+ *
+ * For more detail, please refer to link below:
+ *
https://github.com/opengeospatial/geoparquet/blob/main/format-specs/geoparquet.md#encoding
+ */
+ POINT = 1;
+ LINESTRING = 2;
+ POLYGON = 3;
+ MULTIPOINT = 4;
+ MULTILINESTRING = 5;
+ MULTIPOLYGON = 6;
+}
+
+/**
+ * Geometry logical type annotation (added in 2.11.0)
+ */
+struct GeometryType {
+ /**
+ * Phyiscal type and encoding for the geometry type. Please refer to the
+ * definition of GeometryEncoding for more detail.
+ */
+ 1: required GeometryEncoding encoding;
+ /**
+ * Additional informative metadata.
+ * It can be used by GeoParquet to offload some of the column metadata.
+ */
+ 2: optional string metadata;
+ /** File-level statistics for geometries */
+ 3: optional GeometryStatistics statistics;
Review Comment:
Introducing file-level statistics for all types is a separate topic (perhaps
together with the current v3 discussion). If missing file-level statistics of
geometry type is not a big issue, I prefer to remove this field from the
logical type. In most cases, parquet file unlikely will contain too many row
groups and row-group-level statistics are good enough to use.
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