Do I need topo maps on my hiking GPS?

Any GPS receiver will tell you your current location (latitude, longitude) and elevation - that's what they do. Most units will also display a map screen, with you precisely positioned on it, but the amount of detail displayed on that screen varies enormously.

Some more basic models (or models aimed primarily at other activities such as running) have no map data stored in them. They will show you your "bread crumb" track of where you have been, and also will show "waypoints", which are labeled locations that you either save as you are hiking (for example a peak, campsite, or trail junction that you want to find your way back to later) or preload from your PC before you go.

The next step up are models such as the Garmin eTrex Vista HCx and eTrex Legend which contain a "basemap". This basemap contains cities (their locations, not their detailed streets), major highways, lakes and rivers, railroads, and coastlines. This can sometimes be useful to orient yourself, or for highway driving, but does not add very much once you set out on the trail.

However these two models can also have detailed topographic maps purchased and installed on them, Garmin's MapSource TOPO series. The detail level of these maps vary depending on where you are in the world, but they add the sort of terrain information that you expect from a good topo map: contours, peaks, roads, trails and jeep/mining roads, river/creeks, campsites, trailheads, etc. In some cases these are just as detailed as the USGS 1:24,000 paper maps! The nearby point of interest (POI) database can be searched by name, which can be invaluable in finding you to (or back to) a landmark or trailhead.

Finally, the Garmin Colorado 400t comes with these maps of the US already loaded onto it, so right out of the box it is ready to go out into the wilderness. The Colorado also shows "shaded relief", enhancing the display with shadows to illustrate the terrain.

Relates to:

• Garmin eTrex Vista HCx
• Garmin Oregon 400t
• Garmin eTrex Legend H

Articles Archive

• Dan Neil of LA Times calls Colorado 400t utterly vital
• Can I put street maps on my hiking GPS?
• What to look for in a GPS for backpacking