mkaravel commented on code in PR #15834: URL: https://github.com/apache/iceberg/pull/15834#discussion_r3134505388
########## format/spec.md: ########## @@ -242,10 +242,12 @@ For `geometry` type, the CRS does not affect geometric calculations, which are a 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. -* `projjson`: [PROJJSON](https://proj.org/en/stable/specifications/projjson.html), `identifier` is the name of a table property where the projjson string is stored. +Non-default CRS values are specified by any string that uniquely identifies a coordinate reference system associated with this type. +To maximize interoperability, suggested (but not limited to) formats for CRS are: +* `<projjson>` - A complete CRS definition embedded directly using the [PROJJSON](https://proj.org/en/stable/specifications/projjson.html) specification. Example for `OGC:CRS83`: `{"$schema": "https://proj.org/schemas/v0.7/projjson.schema.json","type": "GeographicCRS","name": "NAD83 (CRS83)","datum": {"type": "GeodeticReferenceFrame"...` Review Comment: You mean as the same entry? They are not same if this is what you have in mind. The plain PROJJSON is expected to be more common than the other one, and the second one is expected to be less common than the authority:code and srid:identifier options. The order in my opinion is good. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
