Joining OSM with contour lines in India (for Garmin)

Hi specialists,

Planning a trip to north-east India I downloaded a selection of tiles from the Lambertus page (gmapsupp.img for my Garmin-Dakota 20, a set of files for BaseCamp). These maps, however, don’t include contour lines. On the other hand, I was informed that there exists a way to download a detailed global world profile from NASA (“STRM”) and/or from But as a newby I have no idea how to join these two types of information. Is there anywhere a kind of manual or procedure (in English or German) of how to download such contour lines and to add them to the gmapsupp.img? Or is it necessary to make such a map from the very beginning, using all these strange programs like JOSM, phyghtmap and such which I never did before :/?

BTW I know already that - once havoing such a map with contour lines - I should not upload it to the OSM server.


Try openmtbmaps,
I’m not sure if they are available for free though.

Firstly, the Dakota 20 can use multiple IMG files, just give them different names, and put them all in the “Garmin” directory. So you don’t need to combine it into a single gmapsupp.img.

As for contours, I’m not sure about any ready made maps for India. There’s some listed here, though not sure how detailed there:


since I created already a map of India for a friend some time ago, I uploaded now the SRTM data, too.
The SRTM data layer contains only the contour lines, nothing else, and can be used on top of other maps for Garmin devices, too. But could be that in that case the draw-priority needs to be changed.



Many thanks to all of you!
Just 2 additional questions to Thorsten:

  1. In a mountaineous area, the SRTM map shows too many contour lines so that you hardly can see the roads behind. Is it possible to change the map in order to just display the 100-m-contour lines? Or is it possible to reduce the line thickness?
  2. Close to a little village named Tezpur in north-east India, the Brahmaputra river is displayed with its correct size only when the scale of the map is 3 km or better wheras it is just a thin blue line when the scale is 5 km or more. This is true just for one little piece of about 20 km of this river. Is it possible to correct this?
    Thanks in advance
  1. You can add this typ file where I stripped the minor contours (10m) by making them transparent. To install them, the contour maps need to be installed on your computer. With Javawa GMTK you can add this typ file to Thorstens contour mapset. With Mapsource or Basecamp you can send the modified contours to your GPS. It should be possible to add a typ file directly to the img with gmaptool or javawa’s typchanger but I havent tried that.
  2. A thin blue line represent a waterway=river line I suppose. Maybe the shape on OSM isnt mapped as area (waterway=riverbank)?

You can adapt the typ file with an editor like typviewer to make the contours thinner or the intermediate contours also transparent (line type 0x21).

Question for Thorsten: you didn’t use the mkgmap option --show-profiles=1 ?

Thanks to ligfietser for his hints.

ad 1) I tried to add ligfietser’s SRTM.TYP to Thorsten’s contour map on several ways. This always resulted in thinner 10m-contour lines, but they did not disappear (which I had expected for “transparent” lines). Any idea why this happened?

ad 2) When the scale is 3 km or less then the river is displayed as a blue area. It is just for scales 5 km or higher when a certain section of the river collapses into a blue line whereas the subsequent sections on both sides remain blue areas. Thus I don’t think that missing data are the reason for that behaviour but probably a wrong priority of this river section. Is it possible to change this in an existing img file?

finally: To make the main contour lines thinner I suppose that I have to add something like


to the lines section of the TYP file. But what should be written in between instead of the question marks so that the srtm map “knows” which contour lines are to be changed to Type=0x21?

I dont know why you still see the contours, maybe you still see the cache (empty it with ctrl G) in Basecamp or Mapsource?
Or do you see them on your Dakota?

The typ file looks like this:

Xpm=“32 1 2 1”
“! c #000000
" c none"
" "
String1=0x04,minor contour
FontStyle=NoLabel (invisible)

Ad 2) which Lambertus map (generic or new style) and exactly what location? Do you see this behaviour in Basecamp?

That’s a bug in the OSM data: parts of the river are tagged with “natural=water” and “waterway=riverside”, others are only with one of the two.


Günter mailed me that this wont happen on the generic new style. This map does not render a line when it is tagged with natural=water, because they are most often areas mapped with waterway=river:

Line style
waterway=river & natural!=water [0x18 resolution 18-20 continue]
waterway=river & natural!=water [0x1f resolution 21 continue]

Polygon style
(waterway=canal | waterway=river) & natural!=water [0x3c resolution 18]

Note that mkgmap will not make a polygon from a non closed line, so only closed waterways will get a 0x3c polygon

But I agree tagging should be corrected in the first place on OSM.