PerryGeo

Feb 08 2006

GDAL-based DEM utilities

55 Responses to “GDAL-based DEM utilities”

1. # Alex Mayrhoferon 08 Feb 2006 at 5:07 am

   You can also combine the hillshade and color ramp images with ImageMagick, eg. by using “composite -compose multiply shade.tif ramp.tif output.tif”. However, the output image might need some value-wise scaling.

2. # Leszek Pawlowiczon 08 Feb 2006 at 11:47 am

   Have you taken a look at Microdem 8/9?

   http://www.nadn.navy.mil/Users/oceano/pguth/website/microdem.htm

   I think it will do much of what you want, and a lot more.

3. # perrygeoon 08 Feb 2006 at 12:24 pm

   Leszek,

   Thanks for the link to MicroDEM. Unfortunately it’s windows only (ouch), doesn’t handle some of the formats I work with and doesn’t have a command-line interface. It looks like a pretty powerful tool, though.. it’s got enough raster analysis tools to rival GRASS or SAGA GIS. I’ll definitely check it out.

4. # Leszek Pawlowiczon 09 Feb 2006 at 12:49 pm

   1. MicroDEM will run in Ubuntu Breezy under Wine for the most part (OpenGL-based functions don’t work, sometimes function windows disappear behind the main window requiring you to resize the main window to find them, and other minor quirks pop up from time to time). I was unable to start it up from a shortcut/link, but it seems to run fine from the Winefile GUI.

   2. In addition to the DEM formats supported by the File => Open DEM command, the Import function in the Data Manipulation window supports a few more DEM formats, some of which may be ones you need to have.

   3. Nope, no command-file option. For this kind of work, though, I tend to have to fiddle around a lot with the parameters to optimize the look. For that, the instant visual feedback of a GUI-based program is far superior to a command-line approach. For scripts and batch processing, though, command-line is clearly superior.

   Wish I had a copy of Visual C++ - I’d like to try these out on Windows. Guess I’ll have to break down and use them in Ubuntu instead.

5. # Rob McCulleyon 11 Jul 2006 at 10:03 am

   Hi Matt,

   I’m trying to compile these, and everything works except for the color-relief.cxx file. I get the following errors:

   stringtok.h:10: error: ‘string’ has not been declared
   stringtok.h: In function ‘void stringtok(Container&, const int&, const char*)’:
   stringtok.h:13: error: ‘string’ has not been declared
   stringtok.h:13: error: ‘size_type’ does not name a type
   stringtok.h:14: error: ‘string’ has not been declared
   stringtok.h:14: error: ‘size_type’ was not declared in this scope
   stringtok.h:14: error: expected `;’ before ‘i’
   stringtok.h:16: error: ‘i’ was not declared in this scope
   stringtok.h:16: error: ‘len’ was not declared in this scope
   stringtok.h:19: error: request for member ‘find_first_not_of’ in ‘in’, which is of non-class type ‘const int’
   stringtok.h:20: error: ‘string’ has not been declared
   stringtok.h:20: error: ‘npos’ was not declared in this scope
   stringtok.h:24: error: ‘string’ has not been declared
   stringtok.h:24: error: expected `;’ before ‘j’
   stringtok.h:27: error: ‘j’ was not declared in this scope
   stringtok.h:27: error: ‘string’ has not been declared
   stringtok.h:27: error: ‘npos’ was not declared in this scope
   stringtok.h:28: error: request for member ‘substr’ in ‘in’, which is of non-class type ‘const int’
   stringtok.h:31: error: request for member ‘substr’ in ‘in’, which is of non-class type ‘const int’
   stringtok.h:34: error: ‘j’ was not declared in this scope
   color-relief.cxx: At global scope:
   color-relief.cxx:35: error: expected constructor, destructor, or type conversion before ‘, std::allocator >, std::allocator, std::allocator > > >]’
   color-relief.cxx:78: error: ‘ColorPointList’ was not declared in this scope
   color-relief.cxx: In function ‘SColor GetColor(float)’:
   color-relief.cxx:101: error: ‘ColorPointList’ was not declared in this scope
   color-relief.cxx:112: error: ‘ColorPointList’ was not declared in this scope

   I’m attempting to compile in Ubuntu 6.06, and I’m rather new to linux, so forgive my ignorance.

   Any Ideas?

   Thanks,
   Rob

6. # Chris Conditon 26 Jul 2006 at 2:10 pm

   So here’s a Makefile for win32. Unzip the code in a directory on under the gdal source tree.
   There are two changes needed for this build:
   1) add “using namespace std;” to stringtok.h
   2) aspect.cpp:165 should become:
   if ((aspect 0))

   Also I don’t think it will link in external libraries right now - depending on what you’re gdal is build with.

   The makefile:
   GDAL_ROOT = ..\

   MORE_LIBS =
   !INCLUDE $(GDAL_ROOT)\nmake.opt

   default: hillshade.exe slope.exe aspect.exe color-relief.exe

   hillshade.exe: hillshade.cpp
   $(CC) $(CFLAGS) $(XTRAFLAGS) hillshade.cpp $(XTRAOBJ) $(EXTERNAL_LIBS) ..\gdal.lib /link $(LINKER_FLAGS)

   slope.exe: slope.cpp
   $(CC) $(CFLAGS) $(XTRAFLAGS) slope.cpp $(XTRAOBJ) $(EXTERNAL_LIBS) ..\gdal.lib /link $(LINKER_FLAGS)

   aspect.exe: aspect.cpp
   $(CC) $(CFLAGS) $(XTRAFLAGS) aspect.cpp $(XTRAOBJ) $(EXTERNAL_LIBS) ..\gdal.lib /link $(LINKER_FLAGS)

   color-relief.exe: color-relief.cxx
   $(CC) $(CFLAGS) $(XTRAFLAGS) /nodefaultlib:libc.lib color-relief.cxx $(MORE_LIBS) $(XTRAOBJ) $(EXTERNAL_LIBS) ..\gdal.lib /link $(LINKER_FLAGS)

7. # Bob Fon 05 Aug 2006 at 5:03 pm

   I am having the same problem as Rob above. The include is not working when compiling color-relief. Any advice on what other libraries need to be loaded under Ubuntu 6.06? The other programs are working.

   Thanks
   Bob F

8. # J Hudsonon 09 Sep 2006 at 7:59 am

   color-relief compiles with gcc 4.x (i.e. Ubuntu 6.06) if you add and move the namespace declaration around in color-relief.cpp, thusly:

   #include
   #include

   #include “gdal_priv.h”
   using namespace std;
   #include “stringtok.h”

   -jonathan

9. # J Hudsonon 09 Sep 2006 at 8:01 am

   Sorry, the blog parser didn’t like the angled brackets, let’s try again

   #include <list> // include systems “list” header file
   #include <vector> // include systems “vector” header file

   #include “gdal_priv.h”
   using namespace std;
   #include “stringtok.h”

10. # J Hudsonon 09 Sep 2006 at 10:15 am

    This stuff is so cool, combined with the gdal/libgeotiff/image magick,
    here’s a small script to convert a GDAL recognised contour file into a
    GeoTIFF, blending the results of hillshade and color-relief
    (sic) as a pretty geo-referenced image.

    #!/bin/sh

    INFILE=$1
    OUTFILE=${2:-hillrelief.tif}
    PID=$$
    hillshade $INFILE .s_$PID.tif -s 370400 -z 20
    color-relief $INFILE scale.txt .c_$PID.tif
    listgeo .s_$PID.tif > .info_$PID.dat
    # The ugly bit. Via a GIF to force 256 colours
    # Otherwise QGIS looks very strange
    composite -blend 50 .c_$PID.tif .s_$PID.tif .geo_$PID.gif
    convert .geo_$PID.gif .geo_$PID.tif
    geotifcp -g .info_$PID.dat .geo_$PID.tif $OUTFILE
    rm -f .s_$PID.tif .c_$PID.tif .geo_$PID.gif .geo_$PID.tif .info_$PID.dat

    Save as mkrelief.sh

    $ mkrelief.sh INPUT output.tif

    Using an SRTM file in ESRI binary grid format (IIRC).
    $ mkrelief.sh w001001.adf iow.tif

    The full (2.5MB) Geotiff may be found
    here.

11. # Hanson 03 Nov 2006 at 2:07 am

    I am having trouble compiling… I am running Fedora Core 5 and have never compiled software so I am sure this is a “user error”
    I get the following errors:
    hillshade.cpp:10:23: error: gdal_priv.h: No such file or directory
    hillshade.cpp: In function \u2018int main(int, char**)\u2019:
    hillshade.cpp:14: error: \u2018GDALDataset\u2019 was not declared in this scope
    hillshade.cpp:14: error: \u2018poDataset\u2019 was not declared in this scope
    … there is more
    I have confirmed that gdal_priv.h exists in /usr/include/gdal

    Is there aproblem with a search path or environment variable that I should set???
    Looking forward to using hillshade with these tools!
    Regards
    Hans

12. # Johnnixon 19 Dec 2006 at 2:24 am

    Hello,

    I want to implement the hillshade code using Delphi but I cannot understand what the win (array) values stand for. Does this array hold the real elevation values?

    Kindest regards

13. # perrygeoon 19 Dec 2006 at 9:04 am

    Johnnix,
    The win array holds the 9 elevation values representing a 3×3 window used to calculate slope, aspect, etc.

    thanks for your interest,
    matt

14. # Johnnixon 21 Dec 2006 at 3:05 am

    Thank you Matt for the prompt reply. I guess now that the shadeBuf holds the new elevation data transformed to a gray scale color value.

    Kindest regards

15. # Paul Surgeonon 21 Dec 2006 at 5:31 am

    A couple of tips :

    1.
    I didn’t write any hillshade and colorized DEM merging functionality because one has far better control inside a graphics app like GIMP or Photoshop.
    Here’s an example of the South Eastern Alps :

    2.
    I prefer to use listgeo and geotifcp for re-applying the projection meta data.
    It tends to be less messy than dragging world files around the place.

    Thanks to Perry for the fine examples he gave me to hack.

16. # Paul Surgeonon 21 Dec 2006 at 5:33 am

    Hmmm … HTML markup didn’t work - here’s the URL : http://img379.imageshack.us/img379/6114/cr1yb2.png
    Oh and I meant South Western Alps. :-$

17. # John Tullon 17 Feb 2007 at 12:10 pm

    This is an excellent set of utilities.

    On Mac OS X, this will build and work fine if you install gdal from source. It will fail using the gdal framework from kyngchaos.com, probably because the libraries are dynamic rather than static.

    I am executing now using the scale.txt colors. Does anyone know of a resource for other color maps that can be used to produce color dems? TIA

18. # John Tullon 17 Feb 2007 at 2:32 pm

    I made my own color map using some satellite images to create a fairly (overly?) complex set of rules. These are designed specifically for Nevada, USA, but might work well in other areas also. Here is the ruleset based on the GRASS r.colors implementation:
    0% white
    3% white
    7% 253 251 203
    20% 185 167 127
    33% 164 140 98
    50% 103 101 50
    60% 54 62 13
    93% 255 255 255
    100% 255 255 255

19. # Dave Robertsonon 04 Apr 2007 at 3:48 am

    To build on OSX using gdal frameworks from KyngChaos.com you need to specify the location of the library and header files, eg:

    g++ hillshade.cpp -I /Library/Frameworks/GDAL.framework/unix/include/ -L/Library/Frameworks/GDAL.framework/unix/lib/ -lgdal -o hillshade
    g++ color-relief.cxx -I /Library/Frameworks/GDAL.framework/unix/include/ -L/Library/Frameworks/GDAL.framework/unix/lib/ -lgdal -o color-relief
    g++ aspect.cpp -I /Library/Frameworks/GDAL.framework/unix/include/ -L/Library/Frameworks/GDAL.framework/unix/lib/ -lgdal -o aspect
    g++ slope.cpp -I /Library/Frameworks/GDAL.framework/unix/include/ -L/Library/Frameworks/GDAL.framework/unix/lib/ -lgdal -o slope

    Cheers, Dave

20. # Dave Robertsonon 15 Apr 2007 at 8:16 pm

    Thanks for making these tools available. They are much easier to work with than grass. Now, can anyone tell me how to convert a shapefile containing contour line vectors into a dem? The shapefile is large (500Mb) and grass seems to run out of memory even on a machine with 2Gb RAM, so does anyone know of a memory-efficient tool or algorithm to do the job?

    Cheers, Dave.

21. # Jeff McKennaon 19 Oct 2007 at 1:04 pm

    Great utility Matt (and contributors). I compiled the 4 utilities on win32 and will include them in the next MS4W release for all to use.

    thanks!

    –
    jeff

22. # Nateon 07 Nov 2007 at 1:43 pm

    I am new to doing any building of gdal libraries. I am working on a Windows system and would like to write some c++ image processing functions using gdal. I am confused about what I need to download, build, install to actually use the gdal header files, etc in my c++ code. Can you or anyone else out there provide me some clear instructions on what steps I need to take?

    Thank you in advance.

    Nate

23. # Jeff McKennaon 16 Feb 2008 at 9:37 am

    By the way, these DEM utilities are now available for windows users as part of MS4W base installer: http://www.maptools.org/ms4w/index.phtml?page=downloads.html

    -jeff

24. # Tyon 10 Apr 2008 at 1:31 pm

    You already provide everything you need to blend the colorized DEM with the hillshade. Simply intergerize your cang variable in the hillshade code and subtract that from 255 (since white = 255 and black = 0). This gives you an integer “darkening” variable. It might look something like this…

    int darkening;

    darkening = 255 - (int)(hillshade.value);

    Then for your final color at a given pixel…

    Color.Red = Color.Red - darkening;
    if( Color.Red < 0 )
    Color.Red = 0;

    … and the same for green and blue.
    If the image is darker than you like, you can either make a brighter color scale by increasing each rgb value or adjust the darkening value by some percentage.

25. # Girishon 16 Apr 2008 at 10:35 pm

    Hi,

    I need to display DTED level0 map in my application,
    can you suggest how to redirect the output to a monitor(preferably to a QWidget) instead of putting it into a file.

    –Giri

26. # Ormon 22 Aug 2008 at 8:06 am

    Very useful tools! You should talk to the GDAL author about getting them included in the official source tree.

27. # John Tullon 11 Sep 2008 at 1:12 pm

    It’s been a log time since I have looked at all of this. I managed to get everything running well on OS X (thanks Dave). I spent some time tweaking the script provided by J Hudson above and came up with on that does a few things. First, a little error checking and a usage example if you do not provide the correct inputs. Second, a check to see if you have a scale.txt file and an example if you do not prior to wasting cpu cycles. And third, the option to save your hillshade separate of the color shaded relief map. I like having these for overlays when making field maps.

    I hope others find this useful. By all means, provide improvements as I am not a scripting pro by any stretch.

    #!/bin/sh

    #****************************************************#
    # makerelief.sh #
    # modified from J Hudson #
    # by John C. Tull #
    # 09/11/2008 #
    # Build shaded relief map #
    # using Matthew Perry’s demtools from: #
    # http://perrygeo.googlecode.com/svn/trunk/demtools/ #
    #****************************************************#

    INFILE=$1
    OUTFILE=$2
    PID=$$
    SCALE=”scale.txt”
    EXPECTED_ARGS=2
    if [ ! -f “$INFILE” -o $# -ne $EXPECTED_ARGS ]; then
    echo “makerelief.sh infile outfile”
    echo “Author: J Hudson Sept. 9, 2006; modified by John C. Tull Sept. 11 2008″
    exit $?
    fi
    if [[ -r $SCALE ]]; then
    echo hillshade $INFILE .s_$PID.tif -s 370400 -z 20
    hillshade $INFILE .s_$PID.tif -s 370400 -z 20
    echo color-relief $INFILE scale.txt .c_$PID.tif
    color-relief $INFILE scale.txt .c_$PID.tif
    echo listgeo .s_$PID.tif > .info_$PID.dat
    listgeo .s_$PID.tif > .info_$PID.dat
    # The ugly bit. Via a GIF to force 256 colours
    # Otherwise QGIS looks very strange
    echo composite -blend 50 .c_$PID.tif .s_$PID.tif .geo_$PID.tif
    composite -blend 50 .c_$PID.tif .s_$PID.tif .geo_$PID.tif
    # echo convert .geo_$PID.gif .geo_$PID.tif
    # convert .geo_$PID.gif .geo_$PID.tif
    echo geotifcp -g .info_$PID.dat .geo_$PID.tif $OUTFILE
    geotifcp -g .info_$PID.dat .geo_$PID.tif $OUTFILE
    echo “Do you want to keep your hillshade? (y/n) ”
    read -n 1 -s answer1
    if [ “$answer1″ == “n” -o “$answer1″ == “N” ]; then
    rm -f .s_$PID.tif .c_$PID.tif .geo_$PID.tif .info_$PID.dat
    exit $?
    else
    echo “What do you want to name your hillshade file? (e.g., hillshade.tif) ”
    read answer2
    mv .s_$PID.tif $answer2
    rm -f .s_$PID.tif .c_$PID.tif .geo_$PID.tif .info_$PID.dat
    exit $?
    fi
    else
    echo “You do not have a scale.txt file!”
    echo “Try:”
    echo ” 3500 255 255 255″
    echo ” 2500 235 220 175″
    echo ” 1500 190 185 135″
    echo ” 700 240 250 150″
    echo ” 0 50 180 50″
    echo ” -32768 200 230 255″
    fi

28. # geoLibroon 30 Sep 2008 at 5:43 am

    I’m a little late here, but wanted to thank you for this very easy (easy w/ Dave Robertson’s OSX tip) suite of tools. Very useful, and great to be able to do this with a swift trip to the command line.

29. # Michal Migurskion 18 Nov 2008 at 12:39 am

    I finally managed to get these compiled on Debian. It was necessary to change the compile flags in the makefile to this, in case it’s helpful to anyone:

    GDAL_LIB=-I /usr/include/gdal/ -L/usr/lib/ -lgdal1.5.0

30. # m.k.ge•o•mat•ics |?j???matiks| › TMS: Shaded Relief for OSM Data (An Adventure and A 1/2)on 20 Dec 2008 at 12:00 am

    […] was created in a primarily two-step process. The hillshade was created using Matt Perry’s GDAL DEM tools. This command line addition to the GDAL suite of tools negated having to import the DEM into a new […]

31. # Jeff L.on 15 Mar 2009 at 10:59 am

    Just leaving this here as reminder to myself, other may benefit too.

    1 - svn checkout http://perrygeo.googlecode.com/svn/trunk/demtools/
    2- vi color-relief.cpp
    #include // include systems “list” header file
    #include // include systems “vector” header file
    #include “gdal_priv.h”
    using namespace std;
    #include “stringtok.h”
    3- g++ color-relief.cpp -L/opt/local/lib -lgdal -I/opt/local/include -o color-relief

32. # Howard Butleron 25 Apr 2009 at 6:42 pm

    These tools will be incorporated in GDAL 1.7+ as the “gdaldem” utility. Thanks for the great work Matt!

33. # research.dmsolutions.caon 08 Jul 2009 at 9:09 am

    […] the recent addition of gdaldem (previously available as DEMtools) to the set of GDAL utility programs, there are now several GDAL programs available for working […]

34. # Lux7on 14 Dec 2009 at 2:51 pm

    Hi Matt,

    I try to use your tools to obtain a hillshading + colorrelief map.
    I have some dted file (dt1).
    Using hillshade the resulting tiff seams good but when I apply color-relief with the default scale.txt file I obtain an all green image.

    What is wrong ?

    my steps are:
    >hillshade filename.dt1 filenameT.tiff
    >color-relief filenameT.tiff scale.txt filenameC.tiff

    Thanks

35. # perrygeoon 14 Dec 2009 at 2:57 pm

    Lux7, make sure scale.txt contains appropriate values for the range of elevation values in your DEM.

36. # Lux7on 15 Dec 2009 at 1:58 pm

    hi, Thanks.
    Once I have the hillshade+color-relief tile (combined) and open it in a gis tool (i.e Qgis),
    how can I get the elevation values from the tile ?

    thanks in advance

37. # perrygeoon 15 Dec 2009 at 2:19 pm

    Lux7,

    You can inspect the *original* DEM using a tool like gdalinfo or QGIS to get the min/max values of that raster.

    In qgis, go to raster properties > symbology > load min max values.

    Using gdalinfo: gdalinfo -mm filename.gt1

38. # Lux7on 16 Dec 2009 at 2:48 am

    Hi Matt,

    I am not interested to get the min/max but for example the elevation values of the entire raster to compute some Line of Sight or something like that. The issue is to get a matrix containing the elevation values of a specified region.

    Suggestions ?

    Thanks

39. # perrygeoon 16 Dec 2009 at 7:12 am

    Lux7,

    The DEM raster, by definition, is a matrix of elevation values.

40. # Lux7on 16 Dec 2009 at 8:49 am

    Yes Ok,
    but I have a picture, so in some way I have to transofrm an RGB value in an elevation value.

    Am I wrong ?

41. # perrygeoon 16 Dec 2009 at 9:01 am

    Lux7,
    Once you’ve created a shaded relief or hillshade or most any other derivative product from a DEM, there is not way to reverse engineer it to get the elevation values. The RGB colors on the shaded relief image are simply R, G and B - it no longer holds ANY information about the original elevation value. Thats what the original source DEM is for.

42. # Lux7on 16 Dec 2009 at 10:10 am

    oh,

    so how can I get an elevation matrix from a lot of dted/dem if for example the region that I want is shared between 2 or more dted/dem files ?

    Is not clear for me.
    Does exists some tool ?

    Lux

43. # perrygeoon 16 Dec 2009 at 10:21 am

    Lux7,

    If I understand correctly, you’re looking to merge or mosaic the rasters into a single file? Try gdal_merge (http://www.gdal.org/gdal_merge.html) or a VRT. Most any image software or GIS software will have capability to merge rasters.

44. # Lux7on 16 Dec 2009 at 11:23 am

    Hi,
    I try to explain me as better as possible.

    I have 2 problems:
    1)Create a color-relief + hillshade map from a lot of dted1 files and open it in qgis.
    To solve this problem I think to use your utility to create the color-relief+hillshade tiles (one for each dted file) and use gdalbuildvrt + gdaladdo to create a virtual raster layer with pyramids. This layer will be loaded in qgis.

    2) Selecting a region of this virtual raster layer (i.e giving the two corner of a box in lat/lon and the number of point in height and width of the box) I want to develop a Qgis plugin that:

    2a)get the elevation values of the region specified by the box and the correct number of point (interpolating if necessary).

    2b)Using the resulting matrix(or buffer) of elevation values make some specific computation like LOS etc.

    any suggetsions to solve it ?

    thanks again for you patience

45. # Hillshade using PerryGeo’s ported GRASS utility « Smathermather’s Weblogon 21 Dec 2009 at 4:55 pm

    […] Using the same LiDAR DEM from which we generated the contours, we can create hillshade tifs using  http://www.perrygeo.net/wordpress/?p=7.  It compiles easily on a mac, probably even easier on a Linux machine following his directions.  […]

46. # Lux7on 08 Jan 2010 at 10:20 am

    hi,

    Why I see the sea green ?
    I have added the line

    0.1 50 180 50
    0 0 0 255

    in the scale.txt

    Thanks

47. # Ceciliaon 11 Jan 2010 at 5:37 am

    Hi!

    I’m using GDALDEM utilities from FWTools shell and I want to make a DSM color relief based on a color text file.

    But I’m having problems in aplying the color blue only to “NoData” pixels.

    This is the color table that I’m using:

    nv 148 184 235
    0 137 90 68
    5 76 115 0
    10 38 115 0
    20 76 92 0
    50 17 69 17

    What can I do to solve this problem?

    Should I classify the noDATA pixels to a specific number like “99″…

    Thanks

    Cecília

48. # Thanhlvon 13 Jan 2010 at 10:08 pm

    @Cecilia
    Just simply add to the end of color text file this line:
    nv 0 0 0

49. # Thanhlvon 13 Jan 2010 at 10:09 pm

    Ops, for blue color:
    nv 0 0 255
    right?

50. # Lux7on 18 Jan 2010 at 10:54 am

    Hi,

    using : nv 0 0 0 I dont’ see blue sea yet. It is still green
    Further suggestions ?

51. # fabon 22 Jan 2010 at 1:10 am

    Do you know the free software SpacEyes3D Viewer / DEM tool box, it’s a graphic interface based on gdaldem that allows to easy handle all gdaldem tools with a friendly QT interface, including a realtime preview (windows only).
    http://technology.slashgeo.org/technology/09/10/29/1632224.shtml

52. # Davidon 30 Mar 2010 at 1:27 pm

    To compile on ubuntu 9.10 I did:
    g++ `gdal-config –cflags` hillshade.cpp -o hillshade `gdal-config –libs`
    etc.

53. # Gabrielon 31 Mar 2010 at 10:11 am

    Dear Matthew

    Please, could you tell me what kind of color ramp and shadow relief image combination algorithm are you using in your color-relief program?

    The problem is common GIS programs usually use a difference or addition algorithm and resulting images look dull but I ‘ve seen an image example at http://wiki.openstreetmap.org/wiki/HikingBikingMaps produced by your program and it looks with nice colors and balanced shadows. It is seems your program conserve color tones and shadows.

    Thanks in advance for your help

54. # perrygeoon 31 Mar 2010 at 10:16 am

    Gabriel,

    The color-relief program does not actually do any shaded relief/shadowing at all. It just assigns colors based on the raster value. You can generate a hillshade map separately and combine them using some of the options discussed in this comment thread (I’m sure there are other ways as well).

55. # Paolo V.on 02 Jun 2010 at 3:31 pm

    This little and powerful toolset saved my day!
    FWTools do not have gdaltodem , and they are not updated either.
    Compiling Gdal on my system is not possible: process is failing after some time.
    I was looking for a linux batch mode for creating a raster image of a dem file, and here I found the solution.
    THANKS!

    I suggest TIFF Tools for linux, and ImageMagick, plus the pnm tools for conversions.

    slope src.tif dst.tif
    tifftopnm dst.tif >dst.pnm
    pnmtojpeg dst.pnm >dst.jpg

    as a workaround to convert into jpeg, because the “convert” tool for TIFF complains.

    Overall, when someone wants to deal with rastering a dem and creating an image of it from linux he has to know that this process is not straightforward nor this simple, because tools involved are complicated , require compiling etc.

    *except THESE tools*

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