v.overlay(1)

1v.overlay(1)                  Grass User's Manual                 v.overlay(1)
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NAME

6       v.overlay  - Overlays two vector maps.
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KEYWORDS

9       vector, geometry
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SYNOPSIS

12       v.overlay
13       v.overlay help
14       v.overlay [-t] ainput=name  [atype=string[,string,...]]   [alayer=inte‐
15       ger]  binput=name  [btype=string[,string,...]]   [blayer=integer]  out‐
16       put=name  [operator=string]   [olayer=integer[,integer,...]]   [--over‐
17       write]  [--verbose]  [--quiet]
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19   Flags:
20       -t
21           Do not create attribute table
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23       --overwrite
24           Allow output files to overwrite existing files
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26       --verbose
27           Verbose module output
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29       --quiet
30           Quiet module output
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32   Parameters:
33       ainput=name
34           Name of input vector map
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36       atype=string[,string,...]
37           Type
38           Feature type(s)
39           Options: line,area
40           Default: area
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42       alayer=integer
43           Layer number
44           A single vector map can be connected to multiple  database  tables.
45           This number determines which table to use.
46           Default: 1
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48       binput=name
49           Name of input vector map
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51       btype=string[,string,...]
52           Type
53           Feature type(s)
54           Options: area
55           Default: area
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57       blayer=integer
58           Layer number
59           A  single  vector map can be connected to multiple database tables.
60           This number determines which table to use.
61           Default: 1
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63       output=name
64           Name for output vector map
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66       operator=string
67           Operator defines features written to output vector map
68           Feature is written to output if the  result  of  operation  'ainput
69           operator  binput'  is true. Input feature is considered to be true,
70           if category of given layer is defined.
71           Options: and,or,not,xor
72           Default: or
73           and: also known as 'intersection' in GIS
74           or: also known as 'union' in GIS (only for atype=area)
75           not: features from ainput not overlayed by features from binput
76           xor: features from either ainput or binput but not those from  ain‐
77           put overlayed by binput (only for atype=area)
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79       olayer=integer[,integer,...]
80           Output layer for new category, ainput and binput
81           If 0 or not given, the category is not written
82           Default: 1,0,0
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DESCRIPTION

85       v.overlay allows the user to overlay two vector area maps.  The result‐
86       ing output map has a merged attribute-table.  The  origin  column-names
87       have  a  prefix  (a_ and b_) which results from the ainput- and binput-
88       map.
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NOTES

91       Currently only areas are supported for the operators or  and  xor!  See
92       also  v.select.   The  operator  defines what kind of operation will be
93       done. Features are written to output, if the  result  of  an  operation
94       'ainput operator binput' is true.
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96       Attributes  of  the tables from ainput and binput are joined into a new
97       table linked to the output maps new cat-column.
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EXAMPLE

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

108       Radim Blazek, ITC-Irst, Trento, Italy
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110       Last changed: $Date: 2007-10-25 17:54:40 +0200 (Thu, 25 Oct 2007) $
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112       Full index
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114       © 2003-2008 GRASS Development Team
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118GRASS 6.3.0                                                       v.overlay(1)