Columbus supports keywords that allow you to define distance PPM errors. Once a PPM error has 
been defined, it will apply to all applicable observations that follow in the file. You can 
turn off the PPM setting at any time by setting it back to zero.



Example:

! Establish PPM errors for Chord Distance observations that follow in the file.
!            PPM (Parts Per Million)
_PPM_CHORD;  7.0

! Define some observations with chord distances
_OBS_AZ_SET;  A; D; 0.0; 0.001; 93.0; 25.0; 106.25; 0.05; 0; 0
_OBS_DIR_SET; FALLS; MINERS; 322.2940; 3.0; NOOBS; NOOBS; 1000.5; 0.0055; 1.5; 1.2; 1
_OBS_HA_SET;  A; B; D; 90.0000; 20.0; 88.0000; 25.0; 93.7500; 0.050; 0; 0
_OBS_CHORD; 101; 102; 3780.260; 0.025; 0; 0

! Now, turn Chord Distance PPM off or change it to another value for chord observations that follow.
_PPM_CHORD;  0





! Establish PPM errors for Chord Distance observations that follow in the file.
!            PPM (Parts Per Million)
_PPM_CHORD;  7.0




! Establish PPM errors for Horizontal Distance observations that follow in the file.
!              PPM (Parts Per Million)
_PPM_HOR_DIST; 8.5




! Establish PPM errors for Height Difference observations that follow in the file.
!              PPM (Parts Per Million)
_PPM_HGTDIFF;  3.2