| Observation type | Code | Units | Format | Default error command |
| slope distances | SD | metres | line/grouped | #ds_error |
| horizontal distances | HD | metres | line/grouped | #ds_error |
| ellipsoidal distances | ED | metres | line/grouped | #ds_error |
| mean sea level distances | MD | metres | line/grouped | #ds_error |
| distance ratios | DR | metres | grouped | #ds_error |
| horizontal angles | HA | *angle | grouped | #ha_error |
| zenith distances | ZD | *angle | line/grouped | #zd_error |
| azimuths | AZ | *angle | line/grouped | #az_error |
| projection bearings | PB | *angle | line/grouped | #az_error |
| levelling data | LV | metres | line/grouped | #lv_error |
| observed longitude | LN | *angle | point | #ln_error |
| observed latitude | LT | metres | point | #lt_error |
| ellipsoidal height | EH | metres | point | #eh_error |
| orthometric height | OH | *angle | point | #oh_error |
| GPS baselines | GB /GPS | metres | line | #gps_enu_error |
| GPS multistation | GB /GPS | metres | grouped/covar | #gps_enu_error |
| GPS point coords | GX | metres | point | #gx_enu_error |
| GPS point coord set | GX | metres | grouped/covar | #gx_enu_error |
Notes:
The code is used to identify the observation type in the #data command
The format refers to the layout of the data block; point format, line format, grouped format, or grouped with covariance format
The default error command is the command used to specify errors of a block of observations in the data file when they are not being explicitly defined for each observation.
*By default angle observations are entered as degrees minutes and seconds, as three separate digits, for example "10 05 47.1". This may be altered by the #hp_angles and #deg_angles commands.