Help requested with Colorado Public Map data

[Boyd]

What kind of GPS do you want to use this in, and how big does the map need to be? If it's a newer device that supports "custom maps" then your easiest path might be to make one of those from Google Earth screenshots (raster imagery). You would be limited by the size of your screen, although you could make multiple tiles.

You would take screenshots of the .kmz file as it appears in Google Earth. I don't use Google Earth - will it let you export a screenshot as a .jpg file? If not, you might need to use something like Grab on the Mac and convert the .tif file to .jpg (non-progressive) in Photoshop. Each .jpg must be no larger than 1024x1024.

Then take those screenshots and line them up with the original in Google Earth and use Garmin's tutorial here: http://www.garmin.com/us/products/onthetrail/custommaps

[Indrid Cold]

.gdb is an ambiguous file extension. Garmin uses it ("Garmin Data Base") to store user data for Mapsource and Basecamp. But most likely, what you have is an ESRI Geo Data Base file: http://www.esri.com/software/arcgis/geodatabase

These are proprietary and I'm not sure that you will find any free software to use them on the Mac. They have been a problem for Windows users as well until Globalmapper recently started supporting them. Globalmapper is a Windows-only program that costs about $400. ESRI's own software costs $$$$$.

Doesn't Quantum GIS (available in native Macintosh format) import ESRI geodatabase in ArcGIS v10 format? Forum LINK

For paid Windows OS GIS software licensing:
Global Mapper licenses can be had for $339.15 through the Global Mapper forum here, with updates being $139.00.
ESRI ArcGIS for Home (noncommercial personal use only) is only $100.00/yr direct.