January 16, 1990
Program COMPGB was written to test the consistency and compatibility of
the B- and G-files for a GPS project. The formats for these files will
be found in Annex N of the FGCC document Input formats and Specifications
of the National Geodetic Survey Data Base, Volume 1, Horizontal Control
Data, January 1989 (also known as the "Blue Book").
A requirement of the National Geodetic Survey (NGS) is that GPS projects
be submitted in computer readable (digital) form. Also, that the data
files be in specific formats, detailed in the Blue Book, which are unique
to the processing and analysis programs which precede the incorporation
of the data into the NGS Integrated Data Base (IDB) and the National Geodetic
Reference System. The file formats for GPS vectors follow the style established
and known popularly as Blue Book files.
COMPGB tests the consistency and compatibility of two of the required
files, i.e., the B-file (GPS Project and Station Occupation Data) and
the G-file (GPS Vector Data Transfer file). To do this, the program requires
a reference, the SERFIL, which is an independently created file of correlated
Station Serial Numbers (SSN) and Four Character Identifications. The four
character IDs are project unique abbreviations of the full station names
which are used in both the B- and G-files. Prior to the use of COMPGB,
the SERFIL should be checked to ensure that all project four character
IDs and SSNs are included and are correct.
Program Function Using the SERFIL as a reference, COMPGB will flag:
1. Occurrences of a SSN/four character ID pair in the SERFIL but not in
the B- and G-files;
Subsequent to using COMPGB and making any necessary corrections,the station
serial numbers and four character IDs used in the B- and G-files will
be consistent within and between themselves the independently created
SERFIL. In addition, one will have an idea which vectors may be missing
from the G-file and which station occupation records are missing from
the B-file. These conditions are errors and must be corrected to have
complete and correct files. Allowed deviations from this are stations
which were occupied but for which vectors could not be computed. These
entries will be noted as informational only.
2. Occurrences of one of the pair in one but not both of the B- and G-files;
3. Inconsistencies of a four character ID or SSN within the B- or G-files
due to typographic errors, etc.;
4. Presence of a four character ID or SSN in a B- or G-file but not in
5. Occurrences of station occupation data in the B-file with no corresponding
vector data in the G-file and, conversely, occurrences of vector data
in the G-file with no corresponding station occupation data in the B-file.
The format for the SERFIL is as follows:
cc 1-4 four character identifier
cc 5-7 blank
cc 8-11 Station Serial Number
Program version 1.1 prompts the user for the names of the input files:
the definitive station list (SERFIL), the G-file, and theB-file. It also
requests the mode of reductions used, single vector or multi (session),
to be calculated and checked against the vectors in the G-file.
Program version 1.2 (19970321) adds the checking of the long vector F
records, formerly only the C records were checked. In addition this version
allows 6000 C/F vectors per G-file, formerly it allowed 90 C vectors per
Program progress will be displayed on-screen, while output will bedirected
to a user specified file (default is screen).
Program version 1.3 (20010713) allows more than 2 bfile *27* records in