COMPGB Documentation

January 16, 1990


Program Overview

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;
    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 the SERFIL;
    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.
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.

The format for the SERFIL is as follows:
    cc 1-4 four character identifier
    cc 5-7 blank
    cc 8-11 Station Serial Number

Execution
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 day.

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 a session.