v.overlay(1)

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

6       v.overlay  - Overlay 2 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]
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19   Flags:
20       -t  Do not create attribute table.
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22       --overwrite
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24   Parameters:
25       ainput=name
26           Name of input vector map
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28       atype=string[,string,...]
29           Type Options: line,area Default: area
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31       alayer=integer
32           Layer number Default: 1
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34       binput=name
35           Name of input vector map
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37       btype=string[,string,...]
38           Type Options: area Default: area
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40       blayer=integer
41           Layer number Default: 1
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43       output=name
44           Name for output vector map
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46       operator=string
47           Operator defines features written  to  output  vector.  Feature  is
48           written  to output if the result of operation 'ainput operator bin‐
49           put' is true. Input feature is considered to be true,  if  category
50           of given layer is defined.
51                 and : also known as 'intersection' in GIS    or  : also known
52           as 'union' in GIS (only for atype=area)      not  :  features  from
53           ainput  not overlayed by features from binput   xor : features from
54           either ainput or binput but not those from ainput overlayed by bin‐
55           put               (only  for  atype=area)  Options:  and,or,not,xor
56           Default: or
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58       olayer=integer[,integer,...]
59           Output layer for new category, ainput  and  binput.  If  0  or  not
60           given, the category is not written.  Default: 1,0,0
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DESCRIPTION

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

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

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

86       Radim Blazek, ITC-Irst, Trento, Italy
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88       Last changed: $Date: 2006/01/02 14:44:52 $
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90       Full index
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94GRASS 6.2.2                                                       v.overlay(1)