Regarding the time differential between the two units, it is indeed true that the time must be known very accurately in the navigation computation in order to get accurate position. One meter of position error is roughly equal to 3 nanoseconds of time error. However, there may be a delay in displaying the time (and position) on one device and not so much in the other, so that they show different times. Rest assured, somwhere inside the receiver, the time is accuratly known. One cannot easily be certain, but the timestamp in the track log is probably taken from the same computations that produce the position, so it probably accurately represents the time you were at the recorded position.

Regarding the displayed accuracy, my experience is that there is no consistent convention on the meaning of “accuracy” or how it should be determined. It’s a statistical thing and there are always many ways to do the statistics. GPS manufacturers use signal strength, number of satellites, satellite geometry and other parameters to estimate the uncertainty in the reported position, but there are factors beyound their ability to measure that play into the errors, too, such as signals that get reflected off of buildings and therefore travel farther to get from the satellite to the receiver (known as multipath). Differential corrections such as from WAAS can only help with certain error sources; they definitely do not help with multipath nor with low signal strength. All this is a long-winded way to say that the “accuracy” reported by the different receivers may not be accurate, itself. So the Legend HCx may actually be more accurate than the 60 CS but may be more conservative the accuracy number it displays. For the record, achieving 1 meter accuracy with a consumer grade receiver, even with WAAS corrections is unlikely; I suspect the 60CS is just optimistic.

One way to get a better idea of a receiver’s true accuracy is to leave it in a fixed location for several hours, then look at the variation in the position reported in the track log. All the apparent motion is due to error. If you plot the track log in Google Earth or a similar tool, the spread of the points gives you an idea of the true accuracy. Compare that with the accuracy reported by the unit while you were collecting the data. Now you have an idea of how trustrworthy the reported accuracy really is.

Frank

Second, I can’t seem to find information on the microSD capacity for the Vista — memory is cheap, but I hate to buy a 4Gb when the unit could handle an 8Gb (or larger). Advice?

As soon as I get the Garmin, I’m downloading your software (and donating to you) — Thanks!

Frank
The plugin handles standard GPX files, which I’m sure all modern Garmen units produce, so you’ll be fine. I’m also sure Garmin can tell you about maximum card size, but I can’t imagine you’d need much space for GPX files…. I once calculated that I could leave the thing on 1-second-interval recording for over a year and still not get close to filling up my 2GB card. Unless you’re planning huge extra maps(?), even a 100-meg card should be fine for most uses. YMMV. —Jeffrey

Thanks,

Marc.

There are donge-type things that just have lights to indicate status…. anything with a modern antenna and a way to get the gpx file to the computer should be fine. —Jeffrey

Have you tried this, and does it work well? What I really need is the road navigation abilities of a windshield/dashboard unit with the battery life, ergonomics, and direct sunlight-viewable screen of a hiking GPS.

I have a map on my miniSD card, but I’ve never tried turn-by-turn directions. I would think the map would have be be encoded specifically for that, and I’m sure mine isn’t, so I don’t think a test on my side would be informative. —Jeffrey

I reached this useful website from google while I was searching GPS devices like Legend HCx because my camera (Fujifilm Finepix S3pro) doesn’t have it.

What I’m concerned is that I really don’t want to hold this device while I’m working or taking pictures. I rather put this device in my backpack, but I was wondering if this device is sensitive enough to receive signals even in the backpack. Have ever tested this? If this didn’t work, how about a pocket? Thanks in advance!

Once it has a signal, it’s fine in a backpack, camera bag, pocket, etc. I find that it gets a signal lock more quickly if in the open, but when I’m in no rush, I just turn it on and throw it in the bag. The biggest problem using it this way is to remember to turn it off when you get home… out of sight sometimes means out of mind, and you wake up the next day to find your batteries in need of replacement. —Jeffrey

I’m thinking about picking up some sort of GPS device before my wife and I fly back to Scotland for Christmas. Any advice? It sounds like you bought yours in the US, but do you have any idea about buying them in Japan? I don’t really know anything much about GPS, but I’m fascinated by the whole idea and I’d love to try it out.