Select/Deselect Direction

Use the Select/Deselect Direction menu option (SELDIR GX) to select lines based on line direction.

Select/Deselect Direction dialog options

Azimuth Direction (°)

Specify the line direction, in degrees azimuth (0 to 360 degrees clockwise) relative to the +Y direction.

Script Parameter: SELDIR.DIRECTION

± deviation (°)

Specify the deviation error in degrees relative to the selection direction. Lines that are within this error of the selection direction will be selected (Default is 15).

Script Parameter: SELDIR.ERROR

Selection

Select if lines with the above version are to be appended or overwritten.

Overwrite current selection: Only the lines with the above version number will be selected/ deselected, regardless of the previous selection pattern.

Append current selection: Apply the selection ONLY to the lines with the above version, and for all other lines with a different version number, the existing selection remains.

Script Parameter: SELDIR.METHOD[0 – Overwrite (default), 1 – Append]

[Select]

Click to select the line.

Script Parameter: SELDIR.OPTION[0]

[Deselect]

Click to deselect the line.

Script Parameter: SELDIR.OPTION[1]

Application Notes

One application is to separate lines of data running in East, West, North and South directions to help determine heading corrections from data sets where this information must be calculated.

An X and Y channel must exist in the database. The first and last points on each line are used to determine the nominal line direction, which is then compared to the test direction. If the line is within the error angle of the desired line direction, the line is selected.