! Columbus supports keywords that allow you to scale standard deviations for each ! observation type. When one of the following keywords is encountered, the ! observation standard deviation it applies to is scaled on Import or when ! using Adjust From File. ! Example: ! Scale all the standard deviations for chord distances by 1.5 when they are loaded from ! the file. _S_CHORD_SD; 1.5 ! This will apply to any chord distances that are below (this keyword) in the file. ! Turn the scaling off (for all chord distances that follow), set _S_CHORD_SD to 1.0. _S_CHORD_SD; 1.0 ! NOTE: ! Some scalars are actually applied to the observation set covariance matrix (not the ! standard deviation). Applying a scalar to a covariance matrix is different than applying a ! scalar to a standard deviation. ! If you apply a scalar of 2.0 to a covariance matrix, that is equivalent to applying a scalar ! or 1.4142 to a standard deviation. ! The easiest way to apply the same scalar to all observations is to use the keyword _ADJUST_APRIORI_FACTOR. This is applied at adjust time (not during import or file loading). ! Following is how to apply the equivalent scalar to a GPS covariance matrix and to chord distance ! standard deviation: ! Example 1: ! Desired covariance scalar is 4.0 _S_XYZ_COV; 4.0 ! Now the square root of 4.0 is 2.0, so use that for the standard deviation scalar. _S_CHORD_SD; 2.0 ! Example 2: ! Desired standard deviation scalar is 3.0 _S_CHORD_SD; 3.0 ! Now the square of 3.0 is 9.0, so use that for the covariance matrix scalar. _S_XYZ_COV; 9.0 ! Scale azimuth standard deviations when loaded from the file. _S_AZ_SD; 1.3 ! Scale direction standard deviations when loaded from the file. _S_DIR_SD; 1.3 ! Scale bearing standard deviations when loaded from the file. _S_BEAR_SD; 1.3 ! Scale horizontal angle standard deviations when loaded from the file. _S_HA_SD; 1.3 ! Scale zenith standard deviations when loaded from the file. _S_ZEN_SD; 1.3 ! Scale chord (slope distance) standard deviations when loaded from the file. _S_CHORD_SD; 1.5 ! Scale horizontal distance standard deviations when loaded from the file. _S_HOR_DIST_SD; 1.5 ! Scale height difference standard deviations when loaded from the file. _S_HGTDIFF_SD; 1.5 ! Scale delta north standard deviations when loaded from the file. _S_DN_SD; 1.5 ! Scale delta east standard deviations when loaded from the file. _S_DE_SD; 1.5 ! Scale delta up deviations when loaded from the file. _S_DUP_SD; 1.5 ! Scale geodesic azimuth standard deviations when loaded from the file. _S_GEODESIC_AZ_SD; 1.7 ! Scale geodesic distance standard deviations when loaded from the file. _S_GEODESIC_SD; 1.7 ! Scale latitude standard deviations when loaded from the file. Only applies ! to latitude coords defined using the _OBS_LAT keyword. _S_LAT_SD; 2.5 ! Scale longitude standard deviations when loaded from the file. Only applies ! to longitude coords defined using the _OBS_LON keyword. _S_LON_SD; 2.5 ! Scale height standard deviations when loaded from the file. Only applies ! to hgt coords defined using the _OBS_HGT keyword. _S_HGT_SD; 2.5 ! Scale north standard deviations when loaded from the file. Only applies ! to north coords defined using the _OBS_NORTH keyword. _S_NORTH_SD; 2.5 ! Scale east standard deviations when loaded from the file. Only applies ! to east coords defined using the _OBS_EAST keyword. _S_EAST_SD; 2.5 ! Scale GPS covariance matrix when loaded from the file. _S_XYZ_COV; 2.0 ! Scale lat, lon, hgt covariance matrix when loaded from the file. _S_LLH_COV; 2.0 ! Scale north, east, hgt covariance matrix when loaded from the file. _S_NEH_COV; 2.0