NAME

v.cutter - Polygon Cookie Cutter (Boolean AND Overlay)
(GRASS Vector Program)

SYNOPSIS

v.cutter
v.cutter help
v.cutter [-u] [-q] cutter=name data=name out=name

DESCRIPTION

This program provides a way to generate new maps based on an intersection of two existing maps. It in effect provides a way to create masked versions of vector maps. Both lines, sites, and polygons are clipped correctly.

OPTIONS

Flags:

-q
Run quietly. Don't print percent information.
-u
Intersect all areas even those that are unlabeled. Not generally useful and also not fully tested.

Parameters:

cutter=mapname
Name of the binary vector file to use for the cookie cutter.
data=mapname
Name of the binary vector file which is to be cut.
out=mapname
Name ofnew vector file to be created.

NOTES

The user must run v.spag -i after running v.cutter to remove identical lines.

The polygons of the cutter map must be labeled to be effective unless the -u flag is specified.

The attributes of created polygons will be generated from the attributes of the data map.

BUGS

There are a few rare situations that are not currently handled correctly. These mostly involve nodes or vertices intersecting exactly with lines of the opposite map. You will know you have hit one of these cases because a lot of strange text will start spitting out.

Currently the program generates many duplicate lines. So v.spag -i must be run on the new file to clean them up. The -i flag specifies to only do the identical line removal phase and is a new option to v.spag in release 4.1. Don't forget to use this flag, as it will run much faster, and will not make any other changes to your data.

Borders between areas with the same attributes are not disolved.

There is no fuzzy data handling code, so expect to see slivers.

There are many places where the code could be optimized greatly.

SEE ALSO

v.spag
v.digit
v.support
v.clean

AUTHOR

Dave Gerdes, U.S.Army Construction Engineering Research Laboratory