jiayuasu commented on code in PR #10981: URL: https://github.com/apache/iceberg/pull/10981#discussion_r1879088058
########## format/spec.md: ########## @@ -1633,3 +1656,15 @@ might indicate different snapshot IDs for a specific timestamp. The discrepancie When processing point in time queries implementations should use "snapshot-log" metadata to lookup the table state at the given point in time. This ensures time-travel queries reflect the state of the table at the provided timestamp. For example a SQL query like `SELECT * FROM prod.db.table TIMESTAMP AS OF '1986-10-26 01:21:00Z';` would find the snapshot of the Iceberg table just prior to '1986-10-26 01:21:00 UTC' in the snapshot logs and use the metadata from that snapshot to perform the scan of the table. If no snapshot exists prior to the timestamp given or "snapshot-log" is not populated (it is an optional field), then systems should raise an informative error message about the missing metadata. +## Appendix G: Geospatial Notes + +The Geometry class hierarchy and its WKT and WKB serializations (ISO supporting XY, XYZ, XYM, XYZM) are defined by [OpenGIS Implementation Specification for Geographic information – Simple feature access – Part 1: Common architecture](https://portal.ogc.org/files/?artifact_id=25355), from [OGC (Open Geospatial Consortium)](https://www.ogc.org/standard/sfa/). + +The version of the OGC standard first used here is 1.2.1, but future versions may also used if the WKB representation remains wire-compatible. + +Possible values for edge-interpolation algorithm (A) for `geography` types are: +* `spherical`: edges are interpolated as geodesics on a sphere. The radius of the underlying sphere is the mean radius of the spheroid defined by the CRS, defined as (2 * major_axis_length + minor_axis_length / 3). +* `vincenty`: [https://en.wikipedia.org/wiki/Vincenty%27s_formulae](https://en.wikipedia.org/wiki/Vincenty%27s_formulae) +* `andoyer-lambert-thomas` +* `andoyer-lambert` +* `karney` Review Comment: ```suggestion * `karney`: [Karney, Charles FF. "Algorithms for geodesics." Journal of Geodesy 87 (2013): 43-55](https://link.springer.com/content/pdf/10.1007/s00190-012-0578-z.pdf), and [GeographicLib](https://geographiclib.sourceforge.io/) ``` ########## format/spec.md: ########## @@ -1633,3 +1656,15 @@ might indicate different snapshot IDs for a specific timestamp. The discrepancie When processing point in time queries implementations should use "snapshot-log" metadata to lookup the table state at the given point in time. This ensures time-travel queries reflect the state of the table at the provided timestamp. For example a SQL query like `SELECT * FROM prod.db.table TIMESTAMP AS OF '1986-10-26 01:21:00Z';` would find the snapshot of the Iceberg table just prior to '1986-10-26 01:21:00 UTC' in the snapshot logs and use the metadata from that snapshot to perform the scan of the table. If no snapshot exists prior to the timestamp given or "snapshot-log" is not populated (it is an optional field), then systems should raise an informative error message about the missing metadata. +## Appendix G: Geospatial Notes + +The Geometry class hierarchy and its WKT and WKB serializations (ISO supporting XY, XYZ, XYM, XYZM) are defined by [OpenGIS Implementation Specification for Geographic information – Simple feature access – Part 1: Common architecture](https://portal.ogc.org/files/?artifact_id=25355), from [OGC (Open Geospatial Consortium)](https://www.ogc.org/standard/sfa/). + +The version of the OGC standard first used here is 1.2.1, but future versions may also used if the WKB representation remains wire-compatible. + +Possible values for edge-interpolation algorithm (A) for `geography` types are: +* `spherical`: edges are interpolated as geodesics on a sphere. The radius of the underlying sphere is the mean radius of the spheroid defined by the CRS, defined as (2 * major_axis_length + minor_axis_length / 3). +* `vincenty`: [https://en.wikipedia.org/wiki/Vincenty%27s_formulae](https://en.wikipedia.org/wiki/Vincenty%27s_formulae) +* `andoyer-lambert-thomas` Review Comment: ```suggestion * `andoyer-lambert-thomas`: Thomas, Paul D. Spheroidal geodesics, reference systems, & local geometry. US Naval Oceanographic Office, 1970. ``` ########## format/spec.md: ########## @@ -1633,3 +1656,15 @@ might indicate different snapshot IDs for a specific timestamp. The discrepancie When processing point in time queries implementations should use "snapshot-log" metadata to lookup the table state at the given point in time. This ensures time-travel queries reflect the state of the table at the provided timestamp. For example a SQL query like `SELECT * FROM prod.db.table TIMESTAMP AS OF '1986-10-26 01:21:00Z';` would find the snapshot of the Iceberg table just prior to '1986-10-26 01:21:00 UTC' in the snapshot logs and use the metadata from that snapshot to perform the scan of the table. If no snapshot exists prior to the timestamp given or "snapshot-log" is not populated (it is an optional field), then systems should raise an informative error message about the missing metadata. +## Appendix G: Geospatial Notes + +The Geometry class hierarchy and its WKT and WKB serializations (ISO supporting XY, XYZ, XYM, XYZM) are defined by [OpenGIS Implementation Specification for Geographic information – Simple feature access – Part 1: Common architecture](https://portal.ogc.org/files/?artifact_id=25355), from [OGC (Open Geospatial Consortium)](https://www.ogc.org/standard/sfa/). + +The version of the OGC standard first used here is 1.2.1, but future versions may also used if the WKB representation remains wire-compatible. + +Possible values for edge-interpolation algorithm (A) for `geography` types are: +* `spherical`: edges are interpolated as geodesics on a sphere. The radius of the underlying sphere is the mean radius of the spheroid defined by the CRS, defined as (2 * major_axis_length + minor_axis_length / 3). +* `vincenty`: [https://en.wikipedia.org/wiki/Vincenty%27s_formulae](https://en.wikipedia.org/wiki/Vincenty%27s_formulae) +* `andoyer-lambert-thomas` +* `andoyer-lambert` Review Comment: ```suggestion * `andoyer-lambert`: Thomas, Paul D. Mathematical models for navigation systems. US Naval Oceanographic Office, 1965. ``` ########## format/spec.md: ########## @@ -1633,3 +1656,15 @@ might indicate different snapshot IDs for a specific timestamp. The discrepancie When processing point in time queries implementations should use "snapshot-log" metadata to lookup the table state at the given point in time. This ensures time-travel queries reflect the state of the table at the provided timestamp. For example a SQL query like `SELECT * FROM prod.db.table TIMESTAMP AS OF '1986-10-26 01:21:00Z';` would find the snapshot of the Iceberg table just prior to '1986-10-26 01:21:00 UTC' in the snapshot logs and use the metadata from that snapshot to perform the scan of the table. If no snapshot exists prior to the timestamp given or "snapshot-log" is not populated (it is an optional field), then systems should raise an informative error message about the missing metadata. +## Appendix G: Geospatial Notes + +The Geometry class hierarchy and its WKT and WKB serializations (ISO supporting XY, XYZ, XYM, XYZM) are defined by [OpenGIS Implementation Specification for Geographic information – Simple feature access – Part 1: Common architecture](https://portal.ogc.org/files/?artifact_id=25355), from [OGC (Open Geospatial Consortium)](https://www.ogc.org/standard/sfa/). + +The version of the OGC standard first used here is 1.2.1, but future versions may also used if the WKB representation remains wire-compatible. + Review Comment: I suggest we put this back as we all agreed during the emails and meetings. This will make things much easier. E.g., readers of the geometry data can filter bbox based on min/max directly without needing to know the lon/lat order in CRS. -- 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
