DESCRIPTION
v.clean allows the user to automatically change (repair) vector files.
The user does not have to run v.build afterwards.
NOTES
What is a bridge?
A bridge is an area type connection of an island (polygon in a polygon) to the outer
polygon. This is topologically incorrect (but OGC Simple Features allow it). v.clean
can be used to optionally change the line type to fulfill the topology rules or to
remove the bridge from the map:
+-------------+ +-------------+ +-------------+
| P| P: polygon | P| | P|
| +---+ | I: island | +---+ | | +---+ |
| | I | | B: bridge | | I | | | | I | |
| | | | : line | | | | | | | |
| +-+-+ | | +---+ | | +-.-+ |
| | | | | | . |
| | B | | | | . L |
| | | | | | . |
+------+------+ +-------------+ +-------------+
EXAMPLES
Snap lines to vertex in threshold
v.clean input=testmap output=cleanmap tool=snap thresh=1
Cleaning OGR imported data (Simple Feature data)
The import of areas with v.in.ogr requires a subsequent run of
v.clean to update the map to a topologically
valid structure (removal of duplicate collinear lines etc). The tools
used for that are 'rmdupl' and 'bpol':
v.clean input=areamap output=areamap_clean tool=rmdupl,bpol
Extracting intersection points of vector lines
v.clean input=lines1 output=lines2 err=points tool=break
Intersection points are written to 'points' map.
AUTHOR
David Gerdes, U.S. Army Construction Engineering
Research Laboratory
Radim Blazek, ITC-Irst, Trento, Italy
Last changed: $Date$