1r.contour(1) GRASS GIS User's Manual r.contour(1)
2
6 r.contour - Produces a vector map of specified contours from a raster
7 map.
8
10 raster, surface, contours, vector
11
13 r.contour
14 r.contour --help
15 r.contour [-t] input=name output=name [step=float] [lev‐
16 els=float[,float,...]] [minlevel=float] [maxlevel=float] [cut=in‐
17 teger] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
18 Flags:
20 -t
21 Do not create attribute table
22 --overwrite
24 Allow output files to overwrite existing files
25 --help
27 Print usage summary
28 --verbose
30 Verbose module output
31 --quiet
33 Quiet module output
34 --ui
36 Force launching GUI dialog
37 Parameters:
39 input=name [required]
40 Name of input raster map
41 output=name [required]
43 Name for output vector map
44 step=float
46 Increment between contour levels
47 levels=float[,float,...]
49 List of contour levels
50 minlevel=float
52 Minimum contour level
53 maxlevel=float
55 Maximum contour level
56 cut=integer
58 Minimum number of points for a contour line (0 -> no limit)
59 Default: 2
60
62 r.contour produces a vector map of specified contours from input raster
63 map. Contours can be produced using a comma-separated list of values
64 in levels, or at some regular increment using the step parameter, using
65 minlevel and maxlevel as minimum and maximum contour values, respec‐
66 tively. If no minlevel or maxlevel is specified, the minimum and maxi‐
67 mum cell values in the input raster map will be used.
68
70 r.contour will either step through incremental contours or produce con‐
71 tours from a list of levels, not both. If both a list of levels and a
72 step are specified, the list will be produced and the step will be ig‐
73 nored.
74 Zero is treated as a valid data value by r.contour.
76 If a contour level exactly matches a category value in the raster map,
78 the contour line may backtrack on itself, causing illegal arcs to be
79 produced in the output vector map.
80 The optional cut parameter allows the user to specify a minimum number
82 of raster cells eligilble to be included in a contour line written to
83 the output vector map. It acts like a filter, omitting spurs, single
84 points, etc., making the output more generalized.
85
87 In the Spearfish location, produce a vector contour map from input
88 raster elevation.dem with contour levels from 1000m to 2000m, 100m con‐
89 tour step, and a minimum of 200 input raster points contributing to the
90 contour line:
91 r.contour input=elevation.dem output=elevation_dem_contours \
92 minlevel=1000 maxlevel=2000 step=100 cut=200
93 For an example of using levels with r.contour this example uses the el‐
95 evation map from the North Carolina database:
96 g.region raster=elevation
97 r.contour in=elevation out=contours levels=60,90,120,150 --o
98 d.mon wx0
99 d.rast elevation_shade
100 d.vect contours color=red
101 Contour lines shown on shaded terrain map
102 For an example of using steps with r.contour this example uses the Li‐
104 DAR data derived elevation map from the North Carolina database:
105 g.region raster=elev_lid792_1m -p
106 r.contour input=elev_lid792_1m output=elev_lid792_1m_contours \
107 minlevel=100 maxlevel=150 step=10
108
110 Terry Baker, U.S. Army Construction Engineering Research Laboratory
111 3/2001: cut parameter and fixes by Andrea Aime (aaime@libero.it)
112
114 Available at: r.contour source code (history)
115 Accessed: Saturday Jan 21 20:38:22 2023
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120 © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
122GRASS 8.2.1 r.contour(1)