[GRASS-user] shaded relief maps & custom color DEM

GRASS GRASS user
1

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?

Thanks
Mark

2

Mark,

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:

http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Raster_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@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?

Thanks
Mark

3

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@nrcan.gc.ca> wrote:

Mark,

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:

http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Raster_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@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?

Thanks
Mark

4

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.

Michael

On 5/24/07 10:26 AM, “M S” mseibel@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@nrcan.gc.ca mailto:epatton@nrcan.gc.ca > wrote:

Mark,

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:

http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Raster_add-ons http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Raster_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@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?

Thanks
Mark

Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics and Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

5

M S wrote:

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.

try the "elevation" rules?

For custom rules, see "r.colors color=rules" in the r.colors help page.

for example:

r.colors mapname color=rules << EOF
0% green
100% 128:128:0
EOF

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?

besides r.shaded.relief + d.his or GIS.m transparency, and NVIZ, in
GRASS 5 there was shade.clr.sh and d.3d. The shade.clr.sh script is just
a modification of r.shaded.relief but I suspect a slightly different
effect from what you are after.

For d.3d try the grass-5.4.0/src/scripts/contrib/d.3d.views script.
Output is much like NVIZ.

Hamish