GVAN: Local Geodetic Vertical Angle Observation

This record specifies a local geodetic vertical angle observation. A vertical angle is measured at the from-station from the horizon up to (positive), or down to (negative), the to-station.

The coefficient of refraction must be from 0.03 to 0.23 (0.13 ± 0.10). If a value less than 0.03 is given, no refraction correction is made. If a value greater than 0.23 is given, it is set to 0.23.

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 short parameter name format is as follows:

Columns 002-005: GVAN
Columns 007-009: Sigma record identifier (see the SIGM record)
Columns 010-010: (blank)
Columns 011-022: From-station name
Columns 024-035: To-station name
Columns 050-050: Sign (-/+/ ) of vertical angle observation
Columns 051-053: Degrees of vertical angle observation
Columns 055-056: Minutes of vertical angle observation
Columns 058-064: Seconds of vertical angle observation
Columns 066-075: Standard deviation of vertical angle observation
Columns 077-086: Coefficient of refraction

The long parameter name format is as follows:

Columns 002-005: GVAN

Columns 007-009: Sigma record identifier (see the SIGM record)
Columns 010-010: * (asterisk)
Columns 011-041: From-station name
Columns 043-073: To-station name
Columns 075-075: Sign (-/+/ ) of vertical angle observation
Columns 076-078: Degrees of vertical angle observation
Columns 080-081: Minutes of vertical angle observation
Columns 083-089: Seconds of vertical angle observation
Columns 091-100: Standard deviation of vertical angle observation
Columns 102-111: Coefficient of refraction