r.shade - GRASS GIS manual

NAME

r.shade - Drapes a color raster over an shaded relief or aspect map.

KEYWORDS

raster, elevation, relief, hillshade, visualization

SYNOPSIS

r.shade

r.shade --help

r.shade [-c] shade=name color=name output=name [brighten=integer] [bgcolor=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-c: Use colors from color tables for NULL values
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

shade=name [required]: Name of shaded relief or aspect raster map
color=name [required]: Name of raster to drape over relief raster map; Typically, this raster is elevation or other colorful raster
output=name [required]: Name of shaded raster map
brighten=integer: Percent to brighten; Options: -99-99; Default: 0
bgcolor=name: Color to use instead of NULL values; Either a standard color name, R:G:B triplet, or "none"

DESCRIPTION
NOTES
EXAMPLES
SEE ALSO
AUTHORS

DESCRIPTION

r.shade will drape a color raster map over a shaded relief map. In place of shaded relief, any raster map can be used including aspect or slope. The color raster map is usually an elevation raster map with colorful color table (as opposed to gray scale color table). However, any raster map can be used including categorical raster maps. The result is a raster map created from elevation and the shade raster.

Comparing to creating shaded relief as semi-transparent overlay on the color raster map, this module gives result with more saturated colors.

The input for this module can be created for example using r.slope.aspect or r.relief.

NULL values are propagated by default, so if any of the two input rasters contains NULL cell NULL will be also in the output. If -c flag is used and cell in color raster is NULL, just shade color is used. If cell in shade raster is NULL, shading effect is not applied and original colors are used. If bgcolor option is used, NULL value in any input raster will be in the output replaced by the given color.

NOTES

Refer to the r.his help page for more details; r.shade is a frontend to that module with addition of brightness support similar to one provided by d.shade. However, note that the brightness is not implemenented in the same way as for d.shade and the results might be different. r.shade is using method described in r.his manual page.

EXAMPLES

In this example, the aspect map in the North Carolina sample dataset is used to hillshade the elevation map:

g.region raster=aspect -p
r.shade shade=aspect color=elevation output=elevation_aspect_shaded

d.mon wx0
d.rast elevation_aspect_shaded

In this next example, a shaded relief raster map is created and used to create a colorized hillshade raster map for later use:

g.region raster=elevation
r.relief input=elevation output=elevation_shaded_relief

r.shade shade=elevation_shaded_relief color=elevation \
    output=elevation_relief_shaded

d.mon wx1
d.rast elevation_relief_shaded

Interesting visualizations can be created using different color tables for elevation raster map, for example using haxby color table. Elevation with shaded relief (hillshade)

Elevation with shaded relief (hillshade)

Figure: A detail of raster created by applying shading effect of shaded relief (hillshade) to elevation raster map from North Carolina dataset elevation map

AUTHORS

Hamish Bowman
Vaclav Petras, NCSU GeoForAll Lab
Inspired by d.shade and manual for r.his.

SOURCE CODE

Available at: r.shade source code (history)

Latest change: Tuesday Dec 17 20:17:20 2024 in commit: ab90c5e5a9b668894da360fa97ffd4a51a38931e