Requirements for Spatial ETL tools

Spatial ETL tools should have the following characteristics:

1. Common Spatial Reference System or Coordinate Reference System Names and Descriptions

2. Coordinate System (and CRS related object) dictionaries. Stuff like the EPSG dictionary.

3. Datum shift lists (towgs84), and datum grid shift files (NTv1, etc).

4. Transformations, calculations, and algorithms written in pseudocode that can be edited in different languages.

5.Descriptions of spatial reference systems that can be used by developers in different programming languages.

6. Notes on transformation from different representations of a CRS (WKT, PROJ.4, GCTP, GML,...).

7. Test suites with test points in a variety of coordinate systems and their lat/long and WGS84 equivelents).

8. Articles on spatial reference systems and translations useful for programmers interested in spatial reference system implementations. For example: Understanding The Difference Between National Vertical Datum of 1929 and the North American Datum of 1988