1v.neighbors(1) GRASS GIS User's Manual v.neighbors(1)
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6 v.neighbors - Neighborhood analysis tool for vector point maps.
7 Makes each cell value a function of the attribute values assigned to
8 the vector points or centroids in a radius around it, and stores new
9 cell values in an output raster map.
10
12 vector, algebra, statistics, raster, aggregation
13
15 v.neighbors
16 v.neighbors --help
17 v.neighbors input=name [layer=string] output=name method=string
18 size=float [points_column=name] [cats=range] [where=sql_query]
19 [--overwrite] [--help] [--verbose] [--quiet] [--ui]
20 Flags:
22 --overwrite
23 Allow output files to overwrite existing files
24 --help
26 Print usage summary
27 --verbose
29 Verbose module output
30 --quiet
32 Quiet module output
33 --ui
35 Force launching GUI dialog
36 Parameters:
38 input=name [required]
39 Name of input vector map
40 Or data source for direct OGR access
41 layer=string
43 Layer number or name
44 Vector features can have category values in different layers. This
45 number determines which layer to use. When used with direct OGR ac‐
46 cess this is the layer name.
47 Default: 1
48 output=name [required]
50 Name for output raster map
51 method=string [required]
53 Method for aggregate statistics (count if non given)
54 Options: count, sum, average, median, mode, minimum, maximum,
55 range, stddev, variance, diversity
56 Default: count
57 size=float [required]
59 Neighborhood diameter in map units
60 points_column=name
62 Column name of points map to use for statistics
63 Column of points map must be numeric
64 cats=range
66 Category values
67 Example: 1,3,7-9,13
68 where=sql_query
70 WHERE conditions of SQL statement without ’where’ keyword
71 Example: income < 1000 and population >= 10000
72
74 This module makes each cell value a function of the attribute values
75 assigned to the vector points or centroids in an area around the cell
76 with a diameter of size around it, and stores the new cell values in
77 the output raster map layer. By default, the module just counts the
78 number of points. The user can also choose amongst a variety of aggre‐
79 gate statistics using the parameter method. These statistics are calcu‐
80 lated on the attributes in the point_column. Using the usual cats and
81 where parameters the user can chose to take only a subset of the points
82 into account.
83 Note that size is defined as the diameter, and so has to be twice the
85 wanted search radius, and that the module works within the current com‐
86 putational region which can be adjusted using g.region. If the vector
87 map falls completely outside the current region, the module will stop
88 with an error.
89
91 Count the number of schools for a given grid (North Carolina sample
92 dataset):
93 g.region vector=schools_wake res=100 -p -a
94 v.neighbors input=schools_wake output=schools_wake_3000m method=count size=3000
95 d.mon wx0
96 d.rast schools_wake_3000m
97 d.vect schools_wake
98 The result gives for each grid cell the number of points (here:
99 schools) not farther than 1500 meter away (half of the given size
100 value) from the respective cell center.
101 Calculate the mean capacity of schools for the same grid:
103 v.neighbors input=schools_wake output=schools_capacity point_column=CAPACITYTO \
104 method=average size=3000
105
107 r.neighbors, v.vect.stats
108
110 Radim Blazek,
111 Moritz Lennert
112
114 Available at: v.neighbors source code (history)
115 Accessed: Saturday Oct 28 18:18:37 2023
117 Main index | Vector index | Topics index | Keywords index | Graphical
119 index | Full index
120 © 2003-2023 GRASS Development Team, GRASS GIS 8.3.1 Reference Manual
122GRASS 8.3.1 v.neighbors(1)