In addition, I tested the waypoint averaging of the Dakota and Vista the Edge dosen't have this function. The averaged waypoint for the Dakota was only 3 inches off the benchmark. This is interesting since the Dakota only used 2 points for the averaging. Garmin evidently is using a new waypoint averaging algorithm with these new units. Waypoint Averaging. The Vista used the old method and averaged every second.
The Vista averaged waypoint was off by 6. Since I was lazy I visually estimated the average waypoint for the Dakota from the tracklog. That average was 1.
For some reason the Edge did not produce a track log. I also took a non averaged waypoint at the end of the one hour period. The Dakota was off 2. The distance from the trackpoint averages were 7.
I looks to me that Garmin changed the way the newer units determine positions. The newer units appear to be more accurate than the older ones. Nice analysis work! Perhaps you could draw up some sort of chart that shows what the satellite constellation arrangement was like during your testing, meaning were the available satellites pretty evenly scattered overhead, or what?
I get a TON of hours from my Vista Cx, easily enough to use for a whole weekend not continuous of course with no worries of carrying spare batteries. Obviously there is no way to run a simultaneous test on the same unit using different software configurations, but my sense is that, with the Vista HCx, the unit seems to perform more erratically with some configurations than with other. And, if the high sensitivity eTrex units use the same chip as that in the Dakota, presumably they both would be prone to similar potential for erratic performance associated with variable software configuration.
It seems to me that putting two or more gps units so close together you'd create electrical interference that might throw them off. I can take an AM radio tuned between stations and bring my garmin 60 cs up to it and you get a noticeable spike in the static. The gps is definitely capable of causing electrical interference.
You might have more valid test results by keeping some distance between them. Great comparisons. I'm surprised you got all three units to zero out on distance to destination. I rarely manage that with one unit, let alone 3 on the same day. I've taken all three of my units to benchmarks a couple times now, but haven't taken all three at the same time, nor done any proper documentation, or testing other than getting an idea, or impression of how they perform.
The Vista was running software version 3. The datasheet uses NAD83, I did not try to do any conversions between the two datums. I've never seen the erratic behavior that some people have had with their eTrex HCX units, maybe I've been lucky. It is curious that all three zeroed out. Looking at the tracklogs and waypoints I wouldn't expect the Vista and Edge to, they seemed to be off. Only thing I can think is there's some filtering going on i. According to the information behind the link you provided, the new methods main advantage is to repeat a standard averaging at several times when the satellite constellation has changed significantly.
You could recreate the method with any "old" unit by averaging waypoints with 90 minutes between the measurements and then average the results manually. The only true advantage of the new method is that it is suggesting the proper time to take the next measurement and that it autmatically averages the averaged waypoints.
Please don't get me wrong, your comparison is by far the best that I have seen so far. But there are some factors which, in case you would like to repeat your test in the future, could be improved:. More importantly, since the units are arranged around!
I would suggest an arrangement resembling a "T" - draw a line from the benchmark, one meter in length, in a known direction 1m north of the benchmark, for example. At the end of this line, place one unit. Place the next unit 50 cm to the west of the first unit, and the third one 50 cm to the east. This way the units would not show the same location, of course, but you still know the true position that each unit should come up with.
Then you can compare each result to the true position of each unit. This may not have anything to do with every day usage, but if you want to truly compare the units you have to eliminate as many sources for errors as possible. You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible.
Paste as plain text instead. Neither model comes with pre-loaded topo maps. The Dakota units have theoretically longer battery life and weigh less 5.
The image below Dakota, left; Oregon, right compares how screen size affects the area you can see covered in terms of map display. While the Oregon has a brighter backlight, the Dakota is a bit more visible under daylight and outdoors conditions.
All of the newer generation high-resolution GPS screens suffer a bit when it comes to visibility, but it seems like Garmin is making some progress in this arena. I do a fair bit of mountain biking, and the Dakota is the first hi-res touch screen unit I consider suitable for fixed mount, non-powered use e.
Nor is it an issue when powered with a car adapter, etc. Visibility was good in direct, full sunlight there were points where it was as bright as my 60CSx in full sun. It looked great in dark shade too. A couple more comments on visibility — my testing was done with the backlight on; I expect this is how most people will use it.
I kept it set to time out at two minutes. The other point is that maps can dramatically affect visibility. The free , scale topo maps available from GPS File Depot example below at right generally do not have this, and they can improve visibility significantly in marginal lighting.
This is a bit off-topic, but it sure would be nice to have a low profile handlebar mount that would allow you to adjust the angle, in two planes, on the fly. The interface is basically the same as that of the Garmin Oregon, with a main menu of 24 items spread across four screens see below. Here are some tips:. The keypad is a little more cramped on the Dakota than the Oregon, due to the smaller screen, but I found that I quickly got used to this and it did not result in a significant increase in errors.
Shown below are the compass and trip computer screens. The data fields can, of course, be customized, as can the background color. The trip computer screen can be also switched to show fewer but larger fields.
You can now slide the map around underneath the pin, and zoom in as needed, to fine tune the selected location..
The Dakota 20 has the same excellent route, track and waypoint management tools found on the Oregon series. These include:. The Dakota is set up for full paperless geocaching support, meaning you can see the description, logs, and hint, and you can log your attempt find, DNF, etc. Speaking of which, full access to these features requires a premium membership at geocaching.
Shown below, clockwise from top left: Closest geocaches, geocache description, menu for a specific cache, and preview map.
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