Q: render a contour layer into an existing map and use it w/ Garmin

Hi there,

I hope I’m sticking to the rules here (as this is my 1st post)…

Here’s what I want to achieve:

**I would like to be able to have an openstreetmap with included contours on my Garmin device in order to do hiking.

Here’s some background info:

  1. I’m using a Garmin Oregon 450 - this device has no capabilities of displaying several layers.

  2. I’m using (preferably) OpenTopoMap (by DerStefan) for hiking.

  3. That map doesn’t include contours.

  4. On www.opentopomap.org, the contours are added as a layer from SRTM.

  5. I understand I can download the SRTS contours only as a map.

  6. I also understand I can download the OpenTopoMap.

  7. I also understand that I can use GMapTool in order to combine maps.

My specific questions would be (I guess):

Is there anywhere a description of how to use GMapTool on an unpacked OpenTopoMap and an unpacked SRTM map so that I receive a combined map - and how I can install that into BaseCamp and my Oregon 450?

Thanks a lot in advance (I hope I picked the correct forum - not sure if I should have posted this directly into the Garmin forum…?)


My Oregon 450 no longer works but I think it supported multiple gmapsupp.img. The garmin package for cyprus from opentopomaps contains two *.img files, so I don’t understand the problem. If you copy both into the garmin folder the device should show two different maps for cyprus and you should be able to enable both.

You can merge multiple individual gmapsupp files into a single file which will display as layers or maps on the Garmin device. It’s a command line option for mkgmap. I used to use it regularly for older etrex devices.

Yes I know that that is possible. Hence, my questions (see my initial post above). However, thanks for letting me know that what I try to do is possible.

I had tried that a couple of times and the SRTM contours just wouldn’t display on the Garmin Oregon.

So I removed all maps from the device and re-installed them (while downgrading to the earlier MapInstall version which seems les buggy.

After a few attemps it worked. Yeah.

Now the OpenTopoMap is displayed and on top, the SRTM contours.

Thanx a lot!

I have just done this successfully using JaVaWa OSM combiner:
The JaVaWawa.nl website says that the JaVaWa tools are no longer supported, but they can still be dowloaded and installed.

  1. Download the Garmin and Garmin contours from for example https://garmin.opentopomap.org.

  2. The downloaded zip files contain one .img map each. Unzip and copy both to the Garmin directory of your GPS device (or SD card).
    If both are selected in the GPS menu, the contours should be visible as an overlay on the GPS device.

  3. The two .img files can be combines into one Basecamp map using JaVaWa OSM combiner https://www.javawa.nl/osmcombiner_en.html
    This creates a 3D map in Basecamp, which may be shown in 3D (Ctrl3), and you can also set a track or route to the map elevation.

  4. The Bascemp version on garmin.opentopo.org maps does not contain contours (even though it is a 3D map), and comes in gmap format suitable for Mac.
    This can be installed on Basecamp for Windows by using JaVaWa GMTK https://www.javawa.nl/gmtk_en.html.

I have also used GMapTool to combine maps, but the JaVaWa tools are much more streamlined and easy to use…