NAME

v.overlay - Overlay 2 vector maps.

SYNOPSIS

v.overlay
v.overlay help
v.overlay [-t] ainput=string [atype=string[,string,...]] [alayer=integer] binput=string [btype=string[,string,...]] [blayer=integer] output=string [operator=string] [olayer=integer[,integer,...]]

Flags:

-t
Do not create attribute table.

Parameters:

ainput=string
Name of input vector
atype=string[,string,...]
Type
Options: line,area
Default: area
alayer=integer
Layer number
Default: 1
binput=string
Name of input vector
btype=string[,string,...]
Type
Options: area
Default: area
blayer=integer
Layer number
Default: 1
output=string
Name of output vector
operator=string
Operator defines features written to output vector. Feature is written to output if the result of operation 'ainput operator binput' is true. Input feature is considered to be true, if category of given layer is defined.
and : also known as 'intersection' in GIS
or : also known as 'union' in GIS (only for atype=area)
not : features from ainput not overlayed by features from binput
xor : features from either ainput or binput but not those from ainput overlayed by binput (only for atype=area)
Options: and,or,not,xor
Default: or
olayer=integer[,integer,...]
Output layer for new category, ainput and binput. If 0 or not given, the category is not written.
Default: 1,0,0

DESCRIPTION

v.overlay allows the user to overlay to vector area maps. There are 3 links attached to features in output map,

NOTES

Currently only areas are supported! See also v.select.

Attributes of the tables from ainput and binput are joined into a new table linked to the output map.

v.db.connect map=outputmap table=ainput.dbf field=2
v.db.connect map=outputmap table=binput.dbf field=3

Attention: Removing the output map will also delete all tables linked to it! Therefore it is advisable to copy tables from ainput and binput first and connect the copied tables to the output map.

EXAMPLE

v.overlay ainput=lake binput=province output=lakeXprovince

SEE ALSO

v.db.connect, v.select, g.copy

AUTHORS

Radim Blazek, ITC-Irst, Trento, Italy

Last changed: $Date: 2004/12/10 09:54:32 $


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