I just checked out the reviews from AntlerPeak's reference. Looks to me like some of the reviewers don't understand what they are trying to review. Others have noted that some of the reviewers don't know the difference between the data and the programs. And some of what they said was simply incorrect.
Just for the record, I own Garmin Topo 100K, Garmin Topo 24K (East), Garmin Metroguide (v4--which is routable on both computer and GPS, no longer available), and National Geographic TOPO! NE. Each has its strengths and weaknesses.
A general observation: the GPS screen is a small window on a large map. If you set the display scale to show small details, you lose the overall situation and conversely, if you set the scale to show the overall situation, it cannot display small details. IMO, the best compromise is to use it at a scale which shows details and use the paper map for the situational awareness. I found it very easy to transfer my location between the map and GPS by inspection.
Another comment: The 100K and 25K scale topo maps (from all manufacturers that I am aware of) are based upon data released by the USGS. So nobody's topos are more up-to-date than the USGS topos. (I have seen a few penciled notations added to NG TOPO! NE before scanning.)
* I used GT 100K for hiking (in a mapping Etrex Vista) for quite a while. (Note that most of the AMC White Mountain maps are at a 95K scale.) When based at home, I kept maps for my local mountains (the Whites) loaded. If I felt like it, I would put in a route with waypoints at the trailheads, junctions, and the summits using a computer. The GPS worked perfectly well either way. The 100K maps were fine for following trails, but I wouldn't plan a bushwack with them. They cover the entire country--not bad for $100.
* I occasionally used the GPS without the local maps loaded. The display was just a set of waypoints on a blank background. It was fine as long as I had a paper map and an appropriate set of waypoints loaded into the GPS. (This is the way that users of non-mapping GPSes operate.) One drawback of this mode is that if you wish to veer off your planned route, you may not have an appropriate set of waypoints to reference your location. You now have to transfer lat-lon (or equivalent) between the GPS and map to use the GPS.
* The Garmin 25K topos were a welcome addition (at least for the areas that they cover). The detail on these maps is essentially the same as the USGS 25K maps. (Of course, they are based upon USGS 25K data...) These are quite adequate for bushwacking, again with the caveat that you should have/need the paper 25K of the area.
* The NG TOPO! maps give you 100K and 25K scanned images of the USGS topos. Nice for planning and printing. You can also transfer waypoints, routes, and tracks.
* The Metroguide maps tend to be more up-to-date than the topos and have a lot more road detail. The routablility (with v4) is nice on the computer, but I give it mixed reviews when used on the road (in a GPSMAP 60cs)--it sometimes does unexpected things which can confuse a driver. And there are some subtle data errors that can cause some funny routes to be generated. Perhaps City Select is better, but I've not used it.
With or without the maps, it is easier to use the GPS for serious navigation if you use it with a computer to manipulate waypoints and routes.
Notes:
* The Garmin Topos are generated from USGS digital line graph (DLG) maps. (small data size, easily scalable, but some detail lost).
* The NG TOPO!s are based upon USGS commissioned scans of USGS paper topo maps (high quality images, not scaleable).
* The Magellan Topos are generated from digital elevation maps (DEM). Some of these maps are inferior to maps based upon the USGS DLG data.
* I haven't mentioned Maptech's Terrain Navigator. (I have no direct experience with it.) It appears to be similar to NG TOPO (some feel it is better).
* In general, if you want to load maps into a mapping GPS, you have to buy the maps from the same manufacturer. Most (virtually all?) consumer computer mapping products and most GPSes will talk NEMA--a standard communications protocol which will allow them to share waypoints, routes, and tracks, but not maps.
* A standard trick for running entirely from hard disk is to copy images of the CD-ROMs on the hard disk and install from there.
* Yes you can choose sets of maps to display on a Garmin GPS by product. (No need to do it map-by-map).
* And finally, self-selected review boards are dominated by those with strong feelings--frequently by those who are unhappy for some reason. The moderates seem to have less to say...
A personal field experience:
Took a trip out to Utah a few years ago with my new Vista. I was able to load in Garmin Topo 100K maps for the southern 1/3 of the state and parts of northern Arizona. No computer. Each evening, I loaded in waypoints and a route for the next day's drive/hike from the front panel. Slow, but it can be done. (I also had appropriate paper maps.) Worked very well. Was very useful for both driving (I was solo) and hiking.
A personal opinion (or two):
* I feel the mapping GPSes are worth the extra cost.
* Even though there is some overlap between the different map sets, I find all useful and tend to use them for different purposes where there is overlapping coverage.
* If you want to navigate by pre-GPS methods, all you have to do is turn it off and put it in your pack. (And you should know how to navigate without the GPS...)
Doug
