OSM Tools
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Creating DEM from hgt files

Examples of maps on Basecamp and a GPS created using Openstreetmap data with newly generated DEM

plain with contours contours and DEM
plain with contours with contours & DEM

Tibet using OSM data

DEM File structure

Most of the file structure is now understood.:

How to show DEM maps in Basecamp

Add DEM sub files to gmap style maps which are placed in c:\programdata\garmin\maps
Basecamp will show 3d maps if it finds .dem files .

In Options,Display change the Elevation Exaggeration to perhaps 200% to make it more dramatic.

DEM plugin for Mapuploader 5 automates this process

1) Point to the .tdb file

2) Select the appropriate .hgt folder

3) Click 'Create DEM'

This adds the necessary DEM subfiles to each map, ie

Product1 -> 42182105
42182105.TRE
42182105.RGN
42182105.LBL
42182105.NOD
42182105.DEM

DEM plugin

How to export DEM maps to a GPS device

Garmin seems to supply most gps devices with a DEM basemap , so why bother ?

Unfortunately, this map is very basic and bland, only showing some 3d features when you zoom out.
It does not accurately represent local features, whereas with the custom created DEM files differences in height within 5 metres are clearly visible.

The process is more involved.

For an example download our gmapsupp 3D of Devon , UK

Maps with DEM on a GPS are not flat maps with shade plotted on top .