That’s a question that keeps coming up, so here is another handheld GPS FAQ. I’ll break this down for folks who need topo or highway maps, and we’ll explore aerial imagery as well…
Topo maps for Garmin handheld GPS
The free option
Garmin BirdsEye Topo US and Canada
Want USGS style topos on your Garmin? Then BirdsEye Topo (shown above at right) is for you. It offers an all you can download subscription plan for $29.99 per year, but if you’re smart about it, you can download whatever you want the first year and not have to pony up again unless you upgrade to a new GPS. Available direct from Garmin.
Tech talk: Raster vs vector
Before we go any further, I should explain the difference in these two types of maps. Vector maps, like the ones from GPS File Depot and Garmin’s new 24K series (discussed below), are made up of data, which show up on your screen as lines and points. Because the files are data, they take up very little memory. They also have an advantage in that you can zoom in and out very far without any blurring.
Raster maps, on the other hand, are made up of images. Examples include Garmin BirdsEye Topo and BirdsEye Satellite Imagery. Since they are image files, they take up a lot more memory. They are also limited by the fact that you can only zoom in or out so far before the image becomes fuzzy.
In the images above, a vector map example is show at left and a raster map on the right.
Topos and Roads: Garmin 24K series
Want the best of both worlds? Garmin’s new 24K topo series offers detailed topographic maps along with routable roads and trails. Highway and points of interest coverage seems to be nearly identical to the City Navigator maps found in their Garmin nuvi products.
Routable roads allow you to use a compatible handheld GPS to navigate to a trailhead waypoint, making this one of my favorite map products. Another advantage is that these maps come with a digital elevation model, giving you shaded relief (although the darker images can reduce visibility on touchscreen models such as the Oregon series). These are available direct from Garmin, and various online merchants, such as Amazon, REI and GPS City. Screenshots below…
Why you should avoid the “t” models with preloaded topos
The “t” model Garmins, like the Oregon 450t come with preloaded 1:100,000 scale topos. I say don’t buy them, going for a version with just a basemap instead. First of all, you can get better quality 1:24,000 scale maps for free (see above). Second, the 100,000 scale roads appears to be based on TIGER data, which is notorious for misplacing roads a hundred feet or so. The primary reason to buy one of these units is if you travel the country extensively and don’t have time to load 24K scale maps. Just know what you’re getting.
Urban cacher? Want pure highway maps? Garmin City Navigator (shown at right) is the way to go, with options as low as $59.99. Just make sure you have a compatible device capable of turn-by-turn routing. Touch screen units work best for this, and it’s ideal to have a mount and a power cord for your car.
OSM: The free option
Open Street Maps produces crowdsourced maps that can be downloaded for free from sites like garmin.openstreetmap.nl and downloads.cloudmade.com. You will get a similar map to the one shown at the right, although road and points of interest coverage probably won’t be as good as with purchased Garmin products.
For urban explorers and folks living in the open landscapes of the American West, Garmin’s BirdsEye Satellite Imagery (shown below) can make a big difference. Just like BirdsEye Topo, the price of admission is $29.99 per year, and while you can still access it once the year is up, with aerial imagery changing all the time it may be worth keeping a current subscription. Available direct from Garmin.
I won’t go into detail about them here, but I have written a couple of posts on this subject before:
Did I miss anything?