[Cdt-l] Garmin GPS - Custom background maps

[bcss at bresnan.net]

I have posted a document with illustrations showing exactly how to obtain
and add free maps to a Garmin SD card which also contains waypoints or
tracks. This will allow users to load waypoints and background maps into
their gps units without requiring a computer. Tested and works on a Etrex 30
and Colorado. Should work on all the newer Garmin devices that use SD cards.


Using the downloaded data, I spent about three hours creating a set of maps
for the entire trail. I made two maps per state and three for MT to match
the waypoint files. Then I did some spot checking against the mapbooks and
the Garmin maps on a gps. The download version seems to me to be usable, but
they are not quite as good as the ones sold by Garmin. I found some coloring
errors where lakes are not shown blue, little stuff like that, but the
positioning seemed fine everywhere I checked. An example - Lake of the Woods
(16_019XR) in WY is not shown blue on the download version, but it is on the
Garmin one. It is identified as a lake in both sets, however, and the
waypoints appear in the same place. 

One nice thing about the downloaded version is that they have smaller file
sizes than the Garmin ones. I easily loaded the multiple sets I made for the
entire CDT into the internal memory of a Etrex 30. If I were hiking the
trail again I would carry printed maps, the downloaded maps on a Etrex, and
the waypoints loaded on SD cards. I would also load the POI's as a backup.

Here is the link

http://www.bearcreeksurvey.com/Data/Topo_Maps_SD_cards.pdf


Enjoy.

best wishes,

Jerry Brown
mailto:bcss at bresnan.net
www.bearcreeksurvey.com