NAME
v.overlay - Overlay 2 vector maps.
KEYWORDS
vector, geometry
SYNOPSIS
v.overlay
v.overlay help
v.overlay [-t] ainput=name [atype=string[,string,...]] [alayer=integer] binput=name [btype=string[,string,...]] [blayer=integer] output=name [operator=string] [olayer=integer[,integer,...]] [--overwrite]
Flags:
- -t
- Do not create attribute table.
- --overwrite
- Force overwrite of output files
Parameters:
- ainput=name
- Name of input vector map
- atype=string[,string,...]
- Type
- Options: line,area
- Default: area
- alayer=integer
- Layer number
- Default: 1
- binput=name
- Name of input vector map
- btype=string[,string,...]
- Type
- Options: area
- Default: area
- blayer=integer
- Layer number
- Default: 1
- output=name
- Name for output vector map
- 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.
The resulting output map has a merged attribute-table. The origin column-names
have a prefix (a_ and b_) which results from the ainput- and binput-map.
NOTES
Currently only areas are supported for the operators or and xor! See also v.select.
The operator defines what kind of operation will be done. Features are written to output,
if the result of an operation 'ainput operator binput' is true.
Attributes of the tables from ainput and binput are joined into a new table
linked to the output maps new cat-column.
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: 2006/01/02 14:44:52 $
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