jiayuasu commented on code in PR #10981:
URL: https://github.com/apache/iceberg/pull/10981#discussion_r1946970567


##########
format/spec.md:
##########
@@ -228,6 +230,30 @@ Notes:
 
 For details on how to serialize a schema to JSON, see Appendix C.
 
+[1001]: <https://portal.ogc.org/files/?artifact_id=25355> "OGC Simple feature 
access"
+
+##### CRS
+
+For `geometry` and `geography` types, the parameter C refers to the CRS 
(coordinate reference system), a mapping of how coordinates refer to locations 
on Earth.
+
+The default CRS value `OGC:CRS84` means that the objects must be stored in 
longitude, latitude based on the WGS84 datum.
+
+Custom CRS values can be specified by a string of the format 
`type:identifier`, where `type` is one of the following values:
+
+* `srid`: [Spatial reference 
identifier](https://en.wikipedia.org/wiki/Spatial_reference_system#Identifier), 
`identifier` is the SRID itself.

Review Comment:
   @redblackcoder `OGC:CRS84` is not an identifier. It is corresponding to the 
following projjson string: 
https://github.com/opengeospatial/geoparquet/blob/main/format-specs/geoparquet.md#ogccrs84-details
   
   It is also equivalent srid:4326 but flip the axis order to lon/lat



##########
format/spec.md:
##########
@@ -228,6 +230,30 @@ Notes:
 
 For details on how to serialize a schema to JSON, see Appendix C.
 
+[1001]: <https://portal.ogc.org/files/?artifact_id=25355> "OGC Simple feature 
access"
+
+##### CRS
+
+For `geometry` and `geography` types, the parameter C refers to the CRS 
(coordinate reference system), a mapping of how coordinates refer to locations 
on Earth.
+
+The default CRS value `OGC:CRS84` means that the objects must be stored in 
longitude, latitude based on the WGS84 datum.
+
+Custom CRS values can be specified by a string of the format 
`type:identifier`, where `type` is one of the following values:
+
+* `srid`: [Spatial reference 
identifier](https://en.wikipedia.org/wiki/Spatial_reference_system#Identifier), 
`identifier` is the SRID itself.

Review Comment:
   @redblackcoder `OGC:CRS84` is not an identifier. It is corresponding to the 
following projjson string: 
https://github.com/opengeospatial/geoparquet/blob/main/format-specs/geoparquet.md#ogccrs84-details
   
   It is also equivalent to srid:4326 but flip the axis order to lon/lat



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org
For additional commands, e-mail: issues-h...@iceberg.apache.org

Reply via email to