[mkgmap-dev] Overview map in gmapsupp.img?

Fri Feb 20 19:30:28 GMT 2015

On 02/20/2015 07:50 PM, GerdP wrote:

> my understanding is that no device supports the overview map.
> It is only used on the PC. Why would you want to have it in the gmapsupp?

I am currently preparing a new update to my topo map of Germany.

The level definition in my options file is:

levels = 0:24, 1:23, 2:22, 3:20, 4:18
overview-levels = 5:16, 6:15, 7:14, 8:12

Without the overview map in the gmapsupp.img my eTrex Legend HCx
displays only the yellow background and the tile borders ("no map") on
all zoom levels down to 50 km. From 30 km onwards it displays the map tiles.

When I load a gmapsupp.img with the overview map inside I get:

800 km - 200 km: White background, national borders, sea; "mapsource"
120 km - 80 km: E-Roads
50 km: Motorroads
30 km: Highway=primary
and so on.

To me this looks like the overview map is perfectly supported by this
gps unit. Zooming and panning in the zoom levels above 30 km is much
faster with an overview map.

Without an overview map the 30 km zoom level shows much more (too much!)
detail (forest, landuse etc.). With an overview map the forest is shown
from 2 km onwards, like I set in the style.

I can put both gmapsupp.img on my server if someone wants to have a look
at it or test it on a different gps unit.