LOCFILE gives the name of an auxillary file to the stations catalog that can contain the station positions. All parameters that can be specified in the LOCFILE can be specified directly in the station catalog and are documented along with that catalog. The station locations used in the default catalogs are from the VLBA correlator data base and are maintained in a very different way from the rest of the information in the station catalog, so it is convenient to have them in a separate file. If a user is making their own catalog, they could put all the information in the station catalog as indeed they must if putting the information into the main schedule through STACAT.
LOCFILE defaults to the standard file distributed with SCHED. If the file is not found, a complaint will only be generated if a stations in the station catalog is missing a position.
Only a subset of the stations catalog parameters can be put in the LOCFILE. They are X, Y, Z, DXDT, DYDT, DZDT, EPOCH, AXISTYPE, and AXISOFF. All other station information must be in the main stations catalog. In addition to these parameters, a catalog version number (VERSION), a station name (DBNAME), and a station code (DBCODE), that might be different from those used in the main stations catalog, should be included. The desired locations catalog entry is identified by giving a matching DBNAME or DBCODE in the main stations catalog to point to the locations catalog entry. The use of different names and codes is an artifact of the use of position information from the geodetic groups which use different station names from those typically used in astronomy. Also the locations file generally contains a separate entry for each pad of an interferometer such as the VLA which is not the case for the stations catalog.