GPSFileDepot Forums

General Category => GPSr Units => Topic started by: pracom on October 12, 2017, 10:09:19 AM

Title: Maps on etrex 20x
Post by: pracom on October 12, 2017, 10:09:19 AM
I'm a new user of maps provided through this website on a new Garmin etrex 20x.
I am trying to understand how the device determines which map to display when more than one is enabled for the same region, e.g. both a topo and OSM map.  Also, how does a transparent map affect this function?
Title: Re: Maps on etrex 20x
Post by: Boyd on October 12, 2017, 10:34:16 AM
Maps have a "draw order" ranging from 0 to 31. A map with a higher number will cover up a map with a lower number. City Navigator has a draw order of 30, so for example, if it was used with a topo map with a draw order of 15 then the topo would be hidden and City Navigator would show if both are enabled.

Transparent overlays are just regular Garmin maps but they have a draw order of 31 which means they will display on top of any other map (since 31 is the maximum). The other unique thing about a transparent overlay is that it contains no background object. A "regular" Garmin map would have a background object that provides a solid color over the entire coverage of the map.

For the topo maps on this site, there simply isn't any standard draw order, so you would have to look case by case to figure out whether one map covers another.

As for OSM, I don't use those and don't know what draw order is standard (if any). You can use a program like Popej's gmaptool to manually change draw orders. I suggest that you first backup any maps before attempting changes in gmaptool.
Title: Re: Maps on etrex 20x
Post by: pracom on October 12, 2017, 12:50:52 PM
Thank you for the detailed response.

So I would presume, based on your information, that something like the background worldwide map that comes pre-installed on the unit, has a very low draw order.
Title: Re: Maps on etrex 20x
Post by: Boyd on October 12, 2017, 02:42:19 PM
Yes, that is a "basemap". IIRC, it would have a draw order of 0 so that any detailed map would cover it up.