Rev 1 – July 2018 Cath-Tech Hexcorder Pro ManualPage 24 of 38GPS DatumChanging the DatumAll GPS units are set to the World Geodetic System 84 datum by default. This is a standardcoordinate system used worldwide with reasonable accuracy. The datum used by the HexcorderPro can be changed to a local datum, however this will change the GPS coordinates stored inthe data, and they will not align with coordinates stored in WGS84.The GPS datum can be changed by adding a datum file to the Hexcorder Pro SD storage. Thedatum is stored in a text file which must be named DATUM.TXT. The datum files can begenerated by a small windows application that Cath-Tech has developed and is available on ourwebsite.Select the datum you wish to use and press the “Save to DATUM.TXT” button. It will open aSave As window which you can use to navigate to the Hexcorder Pro SD storage. The correctDATUM.TXT file name is automatically filled in.Custom datums can be generated using the program if the user has the Major Axis, Flatteningvalue, and DX/DY/DZ values.Available Earth DatumsADINDANAIN EL ABD (BAHRAIN)AIN EL ABD (SAUDI ARABIA)ARATU (BRAZIL)ARC1950ARC1960ASTRO B4 (SOROL ATOLL)ASTRO BEACONASTRO DOS 71/4ASTRONOMIC STATION 1952BD72 (BELGIUM 1972)BEIJING 1954BOGOTA OBSERVATORYBUKIT RIMPAHCAMACUPACAMP AREA ASTROCAMPO INCHAUSPE(ARGENTINA)CAPECARTHAGECHAD (WG1998)CLARKE 1866 AUTHALICSPHERECORREGO ALEGRE (BRAZIL)D-48 SLOVENIADEALUL PISCULUI 1970DEIR EZ ZOR (SYRIA)DUTCH (RD)EASTER ISLAND 1967ED50ED50 (ENGLAND)ED50 (FINLAND/NORWAY)ED50 (GREECE)ED50 (ITALY)ED50 (NORTH SEA)ED50 (NORWAY OFFSHORE -N62)ED50 (NORWAY OFFSHORE -S62)ED50 (SICILY)ED50 (SPAIN/PORTUGAL)ED79ED87EGYPT 1907EGYPT GULF OF SUEZ S-650 TLESTIONIA 1997ETRF2000 - RDNETRS89FD 1958 (IRAQ)FINLAND/HAYFORDGDA 94 (AUSTRALIANGEODETIC 1994)GGRS87 (GREECE)Figure 26 - GPS datum file generator