[mkgmap-dev] How to install maps with DEM onto a GPS

Tue Oct 31 11:00:52 GMT 2017

Hi All

I offer one possible solution for installing a DEM map on a GPS using
Garmin's Mapinstall.
Its not ideal but it works once you take account of the following:

After much frustration, I think I have resolved the problem with Mapinstall.

It seems that Mapinstall ,more often than not,  detects an issue with one of
the files created using mkgmap's -gmapi option.
 I have not tried to work out which one but I can say that ,so far, all
gmaps created using Javawa Mapconverter have formed a successful basis for
uploading dem maps to a gps device.

1) Create your Mapsource/Basecamp map using mkgmap 
Ignore the gmap if created by mkgmap
drag your mapfolder onto Javawa's mapconcerter to create a new gmap - place
this in c:\programdata\garmin\maps

2) I use Franks excellent program to create & add dem files

3) I add DEM file sizes to the .tdb file - I have presumed that all dem file
sizes require a maximum of 4 bytes - I have not encountered files which
require 5 bytes - please let me know if is a DEM file which needs 5 byte.

4) I have not had to add or replace separate bytes in the tdb file to make
it work apart from setting the DEM flag

5) If some maps have no dem then no dem height or ref to a DEM is added to
the tdb 

6) I now use Mapinstall and upload map to my GPS.

This is one solution which now seems to work.

As this is rather long winded, you don't really want to do this each time
you update a map!

 Perhaps we need to look at ways of  creating 'empty' maps with just DEM as
a separate gmapsupp.

examples on Oregon:

Greece :

<http://gis.19327.n8.nabble.com/file/t339487/241.bmp> 

<http://gis.19327.n8.nabble.com/file/t339487/265.bmp> 

<http://gis.19327.n8.nabble.com/file/t339487/350.bmp> 

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