Check segments : Self overlap

Checks whether segments partly overlap themselves and intersect themselves. This check should be used when you wish to polygonize your segments.

Dialog box options:

Mask:	Select this check box if you want to check a specific selection of segments. Subsequently, specify the multiple search strings to check only those segments. Clear this check box to check all segments.
Start at Begin:	Start the check with the first segment.
Start at Number:	Start the check with any segment. Subsequently, type the (internal) segment number where the check should start. Previous segments will be skipped.

If a self overlap is found:

the overlap is marked on the map with a red square;
a message box appears stating the code of the segment and the (internal) segment number, asking you to zoom in on the error or not.

Whether you let the program zoom in automatically or not, you have to correct the error manually, for instance by using Move Points Mode.

If a self intersection is found:

the self intersection is marked on the map with a red square;
a message box appears asking you to zoom in on the error or not;
whether you let the program zoom in or not, a subsequent message box will appear stating the code of the segment and the (internal) segment number, asking you to remove the false polygon or not:

Yes: remove the false polygon, and continue checking, or
No: another message box will appear, asking whether you wish to split the segment at the intersection:

Yes: split the segment at this intersection, and continue checking, or
No: return to the segment editor in Move Points Mode, and manually correct the error.

After an automatic correction, the check will be continued automatically; after a manual correction, you have to restart the check yourself.

If no errors are encountered for this check, a message will appear stating that the segments are OK.

Segment editor