Colorado 400t topo map vs City Navigator

[Geoforce4]

My wife and kids purchased a Colorado 400t for my birthday. They want me to learn it and go geocaching with them. While I have experience with aviation related GPS, this is my first time to try handhelds. If this question has been answered before, please point me in the direction of the right thread!

 

The Colorado is showing satellite accuracy of 11 feet outdoors and up to 94 feet indoors, but the map display is off by about 500 feet. I realize that the topo maps aren't street maps, but the disparity surprised me. Will loading City Navigator "cure" this issue for suburban geocaching application? My kids will be the primary user, and the map inaccuracy will make it more difficult for them.

 

If City Maps won't work, are there any suggestions (besides returning it) that might/will? The handheld is running July 18 release software (2.60). I'm starting to realize from reading here that the Colorado series isn't Garmin's best effort.

 

Thanks in advance

[+twolpert]

Nothing wrong with your EPE figures. 11 feet is normal for outdoors, little or no cover and a decent satellite constellation. High figures, like 94 feet, are to be expected indoors. The Colorado has a high-sensitivity chipset which is subject to multi-path issues.

 

The street locations in Colorado topos are notoriously bad. Interstate highways, state highways, and urban arterial roads are usually fairly accurate. However, side streets are not. Although I have never actually paid any serious attention, I would not be surprised to see errors on the order of a few hundred feet, at least in places. I have also seen one or two posts which report very large, systematic street map errors (where a whole set of streets is displaced by 500 feet or more) in very localized portions of the map set.

 

Bad map data does not make a bad unit. To differentiate between bad map data and actual location errors, I would first try taking the unit in the car along major highways or roads. If your track on the map is reasonably close to reality, it's likely just bad mapping data for smaller streets. If not, you might actually have a problem -- but it seems unlikely.

 

The other thing to do is to compare your reported location with a known good location. If there's a benchmark in your neighborhood, head on over there and see what you get.

 

Yes, the CN maps work well with the Colorado. The street data in CN is excellent. Some cachers actuallly use CN to route to the cache, then switch to off-road routing for the actual find. I don't do that myself since I usually cache in parks. But it certainly does work. However, before you spend the bucks, you might want to see if bad side-street maps really interferes with your geocaching. Once in the vicinity of the cache, most people rely on the pointer and distance information, not on the map. After you get a little experience, you may find that the map problems are not as big a deal as you thought.

 

One other note: Unlike the street mapping, the topographic information on the 400t IS accurate -- at least given the 1:100000 maps which were used as the basis.

[+paulmc]

It's disappointing to hear that the 400t has such inaccurate streets, even though that's secondary to terrain for a topo map. I use Topo Canada in my eTrex and the street data is several years old, but I've never seen anywhere near 500 feet inaccuracy for a street - and local streets are displayed better than highways I've travelled throughout Atlantic Canada.

 

- Paul