[GRASS-user] shaded relief maps & custom color DEM
michael.barton at asu.edu
Thu May 24 15:26:42 EDT 2007
In addition to these, you can use d.his with a new brightness enhancement
(thanks to Hamish) to display a color map (in the hue field) draped over a
shaded relief map (in the intensity field). This is built into the GUI for
raster display, where you can drape a color map over a shaded relief map and
enhance the brightness. Transparency is also built into the GRASS GUI,
allowing you to display a relief map and overlay it with a semitransparent
color map. Finally, you can also display very nice looking relief maps using
NVIZ. Use a DEM (not shaded relief map) for the base map and any color
raster you want for the coloration of the base map.
On 5/24/07 10:26 AM, "M S" <mseibel at gmail.com> wrote:
> Thanks to Pablo and Eric.
> Pablo's solution is a good one for a quick output. The transparancy seems to
> decrease the richness of the color DEM, but still produces good results.
> Eric's solution is marvelous. It retains the rich color of the input color
> DEM (I used the "elevation" color ramp) and integrates shaded relief. Very
> cool! Thanks for the direction to the right tools for the job. While I have
> yet try the script he wrote, that looks cool too.
> Thanks to both for the help. These will create some very nice illustrations.
> On 5/24/07, Patton, Eric < epatton at nrcan.gc.ca <mailto:epatton at nrcan.gc.ca> >
>> The grass commands you are looking for are r.his and r.composite.
>> r.his uses a coloured DEM as the hue component, and the shaded-relief map as
>> the intensity component. The saturation component can be left blank in this
>> case. r.his will output 3 maps, one each for red, blue and green color
>> components, which you can then combine together in one map with r.composite.
>> You may be interested in trying out a script I wrote called r.csr that
>> integrates all these steps in the Grass Add-ons:
>> r.csr allows you to input one or more rasters using a wildcard search
>> pattern, and can apply color rules, shading parameters, and the r.his and
>> r.composite steps described above all in one go.
>> Hope this helps,
>> ~ Eric.
>> -----Original Message-----
>> From: grassuser-bounces at grass.itc.it on behalf of M S
>> Sent: Thu 5/24/2007 11:29 AM
>> To: grass user
>> Subject: [GRASS-user] shaded relief maps & custom color DEM
>> Hello all!
>> I have been exploring the best way to make a shaded relief map with color
>> gradient. Although I have been using GIS for many years, this is a new
>> topic for me. (New is always fun, especially with GRASS!)
>> I have several questions relating to this topic.
>> 1) I have used r.color to change the color gradient for the DEM I am
>> using. There are a lot of nice palettes to use! One that I am looking for
>> is a tan to green gradient (tan=high elev, green=low). There are some nice
>> ones that are close, but is there a way to create a new color map going from
>> color #1 to color #2? In the mean time, the red to yellow to blue is
>> working well.
>> 2) r.shaded.relief creates some nice outputs! very cool. I have a ryb
>> color map for the DEM, and have created a shaded relief map that is
>> grayscale. Is there a way to make a color shaded relief map? I have been
>> looking for examples illustrating the tools to use in GRASS that will do
>> this. I found r.blend, and it seems to produce something very close, if not
>> exactly what I am looking for with more tuning of parameters. Is this the
>> best combination of tools to use? --> r.color on DEM + r.shaded.relief +
>> r.blend = color ramped shaded relief map?
>> 3) I have done a fair amount of researching the web for color shaded relief
>> maps, but was unable to find techniques relating to GRASS production of
>> these datasets, or a gallery of shaded relief maps produced by GRASS. Does
>> anyone know of such a link?
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics and Complexity
Arizona State University
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