The datum mapping file (datummapping.dat) maps BSB/HCRF datum codes to Well Known Text (WKT) equivalents. This provides a means to define or override the transformation to WGS 84 for various HCRF and BSB datums.
The datum mapping file provides definitions for datums that are unknown to CARIS software. Unknown to CARIS software means that the datum definition does not provide information about how to transform positions to WGS 84. This would include datum definitions found in some BSB and HCRF files. datummapping.xml is pointed to by the environment variable uslXDatumMapping.
The Datum Mapping file is located in C:\Program Files\CARIS\HPD Suite\<version>\system.