Coordinate Reference System Linking File

The boundcrs.dat file associates (links) coordinate reference systems to datum transformations.

Datums are defined in datum.dat or epsg.db. However, two datums are exclusive to this file:

• RDNAP For use with compound coordinate reference system

Uses the RDNAPTRANS™ method and the following grid shift files: nlgeo04.grd, x2c.grd, y2c.grd.

• NTFRFG93_4275 and NTFRFG93_4807: For use with coordinate reference system that have a base geodetic coordinate reference system of EPSG:4275 and EPSG:480 respectively. Use the NTv2 method, requires the grid shift file ntf_r93.gsb.

The file format is:

CRS_ID,EPSG-CRS-ID,DatumTxID

where:

• CRS_ID is a unique identifier for the link (mapdef lookup key or EPSG link)

• EPSG-CRS-ID is the EPSG identifier for the coordinate reference system.

• DatumTxID is the identifier for a datum transformation. N/A can be entered for no transformation.

Sample

Entries from boundcrs.dat: