r.median(1)

1r.median(1)                   Grass User's Manual                  r.median(1)
2
3
4

NAME

6       r.median   -  Finds  the  median  of values in a cover map within areas
7       assigned the same category value in a user-specified base map.
8

KEYWORDS

10       raster
11

SYNOPSIS

13       r.median
14       r.median help
15       r.median base=name cover=name output=name   [--overwrite]   [--verbose]
16       [--quiet]
17
18   Flags:
19       --overwrite
20           Allow output files to overwrite existing files
21
22       --verbose
23           Verbose module output
24
25       --quiet
26           Quiet module output
27
28   Parameters:
29       base=name
30           Name of base raster map
31
32       cover=name
33           Name of cover raster map
34
35       output=name
36           Name for output raster map
37

DESCRIPTION

39       r.median  calculates  the  median category of data contained in a cover
40       raster map layer for areas assigned the  same  category  value  in  the
41       user-specified  base  raster map layer.  These median values are stored
42       in the new output map layer.
43
44       The output map is actually a reclass of the base map.  The base  map is
45       an  existing raster map layer in the user's current mapset search path.
46       For each group of cells assigned the same category value  in  the  base
47       map,  the  median  of  the values assigned these cells in the cover map
48       will be computed.
49
50       The cover map is an existing raster map layer containing the values  to
51       be used to compute the median within each category of the base map.
52

NOTES

54       The  user  should  use  the  results of r.median with care.  Since this
55       utility assigns a value to each cell which is based on global  informa‐
56       tion  (i.e., information at spatial locations other than just the loca‐
57       tion of the cell itself), the resultant map layer is only valid if  the
58       geographic  region  and  mask settings are the same as they were at the
59       time that the result map was created.
60
61       Results are affected by the current region settings and mask.
62

EXAMPLE

64       Median K-factor (erosion) for Spearfish fields:
65       g.region rast=fields -p
66       r.median base=fields cover=soils.Kfactor output=K.by.farm.median
67       r.univar K.by.farm.median
68
69

AUTHOR

76       Michael Shapiro, U.S.Army Construction Engineering Research Laboratory
77
78       Last changed: $Date: 2007-10-10 10:01:00 +0200 (Wed, 10 Oct 2007) $
79
80       Full index
81
82       © 2003-2008 GRASS Development Team
83
84
85
86GRASS 6.3.0                                                        r.median(1)