szehon-ho commented on code in PR #240:
URL: https://github.com/apache/parquet-format/pull/240#discussion_r1597394210
##########
src/main/thrift/parquet.thrift:
##########
@@ -270,8 +270,11 @@ struct Statistics {
* may set min_value="B", max_value="C". Such more compact values must
still be
* valid values within the column's logical type.
*
- * Values are encoded using PLAIN encoding, except that variable-length byte
- * arrays do not include a length prefix.
+ * Values are encoded using PLAIN encoding, except that:
+ * 1) variable-length byte arrays do not include a length prefix.
+ * 2) geometry logical type with BoundingBoxOrder uses max_value/min_value
pair
Review Comment:
This is great to have as part of statitics, but trying to wrap my head
around how writer implementations in WKB case can get min_value/max_value, not
sure if they have the bounding box easily unless they deserialze. I think
that's where the advanced geospatial encoding can be more beneficial.
##########
src/main/thrift/parquet.thrift:
##########
@@ -373,6 +376,69 @@ struct JsonType {
struct BsonType {
}
+/**
+ * A geometry can be any of the following subtypes.
+ * The list of geospatial subtypes is taken from the OGC (Open Geospatial
Consortium)
+ * SFA (Simple Feature Access) Part 1- Common Architecture.
+ */
+enum GeometrySubType {
+ POINT = 0;
+ LINESTRING = 1;
+ POLYGON = 2;
+ MULTIPOINT = 3;
+ MULTILINESTRING = 4;
+ MULTIPOLYGON = 5;
+ GEOMETRY_COLLECTION = 6;
+}
+
+/**
+ * Interpretation for edges, i.e. whether the edge between points
+ * represent a straight cartesian line or the shortest line on the sphere
+ */
+enum Edges {
+ PLANAR = 0;
+ // SPHERICAL = 1; // not supported yet
+}
+
+/**
+ * Well-Known Binary. This is a well-known and popular binary representation
regulated
+ * by the Open Geospatial Consortium (OGC).
+ */
+struct WKB {}
+/**
+ * Encoding for geospatial data.
+ */
+union GeospatialEncoding {
+ 1: WKB WKB
+}
+
+/**
+ * Geometry logical type annotation
+ *
+ * Allowed for physical types: BINARY (added in 2.11.0)
Review Comment:
In the proposal
https://docs.google.com/document/d/1iVFbrRNEzZl8tDcZC81GFt01QJkLJsI9E2NBOt21IRI/edit#heading=h.kierb15tccn8
we explored more advanced geospatial encodings (using group). are we still
considering that, and wondering how we will support those?
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