Map Priorities and Layering.

**losted** · 21st October 2010, 11:37 PM

Hi all, great site!
Have been lurking for a while and scanning Indexes but could not find anything about Garmin Map priorities and Map overlay conventions.
If anybody could point me to some references it would be appreciated.
Tks.

Kanopus · 22nd October 2010, 12:40 AM

Garmin can display multiple map at once. What you will see, which map will be on top, depends on 2 main factors:
- type of the map
- internal map priority and transparency settings

There is a list indicating priority according to map typ, from the top to bottom:
City Navigator
City Select
MetroGuide
BlueChart
Fishing Hotspots
Water Waypoints and Lights
Road & Recreation
Topo
WorldMap

I'm not sure how precise is this list, but i can confirm, that type of the map is important.

Second factor is draw priority. It is a number in range 0-31 hidden inside img. This value can be edited by some tools. Map with bigger priority are displayed over other maps.

Map can have transparency attribute. It makes map polygons invisible. Transparent maps are displayed over non-transparent maps.

Both factors are used by GPS when drawing maps, but i really don't know, how exactly draw order is calculated. Draw priority is a simple number, changing it gives expect effect, but it is difficult to tell, how map type is converted or compared to priority numbers.

**losted** · 22nd October 2010, 09:38 AM

Thanks Kanopus. I'll see what I can do with that info.

Losted

**DTPM** · 25th August 2012, 04:51 PM

On my SD card I have four maps of the same country merged with Gmaptool.

If I have all maps 'turned on' in my 'settings, map, map info' will my garmin just select the most appropiate map for the road im on or does it prioritise the garmin maps first?

The reason I ask is I am going to a remote part of India, CN only has main roads, MapMyIndia seems to have more, India Satguide maps had some different streets and a Himalaya map has a chunk of my journey. Am I better off leaving everything turned on and let the machine (Zumo 660) figure it out, or, do I keep checking maps as I go to see which is suitable?

**DTPM** · 26th August 2012, 10:32 AM

Had a good read.

Apart from CN taking priority, Im none the wiser

grv2k5 · 26th August 2012, 12:13 PM

The one in the SD card would always take priority

**catymag** · 26th August 2012, 12:16 PM

Originally Posted by grv2k5

The one in the SD card would always take priority

I would like to know where you got this info-

**DTPM** · 26th August 2012, 05:02 PM

Originally Posted by grv2k5

The one in the SD card would always take priority

All of the maps are on a SD card.

Apart from CN taking priority I dont think anyone can give me an answer as map priority depends on a hidden number in the maps.

**catymag** · 26th August 2012, 06:39 PM

It depends also on the device. In my 62 for example ,map drawing priority is completely different than in nuvis.
Must manage maps showing ,using profiles coz some topos always hide other maps ,even CN.

This thread merged with the previous one.