OHDF: Orthometric Height Difference

This record specifies an orthometric height difference observation.

This record has two possible formats, a long parameter name format, and a short parameter name format. If column 10 contains an asterisk (*) the long name format is expected, otherwise the short name format is expected.

The “Distance between stations” field is used to apply the Sigma record PPM field to the observation variance. This field is optional and if not provided it will be calculated by GeoLab as long as the stations have their 2D (latitude/longitude, etc.) location provided.

This field is not treated as a spatial distance observation.

The short parameter name format is as follows:

Columns 002-005: OHDF
Columns 007-009: Sigma record identifier (see the SIGM record)
Columns 010-010: (blank)
Columns 011-022: Station name of from-station
Columns 024-035: Station name of to-station
Columns 050-064: Orthometric height difference observation
Columns 066-075: Standard deviation
Columns 077-091: (optional) Distance between stations
Columns 093-094: Linear unit name

The long parameter name format is as follows:

Columns 002-005: OHDF
Columns 007-009: Sigma record identifier (see the SIGM record)
Columns 010-010: * (asterisk)
Columns 011-041: Station name of from-station
Columns 043-073: Station name of to-station
Columns 075-089: Orthometric height difference observation
Columns 091-100: Standard deviation
Columns 102-116: Distance between stations
Columns 118-119: Linear unit name