accuracy of trip odometer

[schandler]

Probably an obvious answer but...  I have a dakota 20 and hike around in the hill/mountains, etc. It works great for location, and mapping etc. However i notice that most of the time when i finish a hike the trip odometer for distance is usually a lot less than the actual route/track distance that i recorded. Is this due to elevation changes or periodically losing signal?

thx
scott

[Boyd]

I'm not sure, but the odometers on all the different units I've owned never seem very accurate to me...

[Jimbob]

I'm going to hazard a guess that the track/route distance is computed by whatever standard  (time/distance so on) that is selec ted, but the trip odometer for distance is line of sight  As the crow flies. this is somwhat born out when using waypoints as go to points. Straight line it is.

[alpine]

On the Nuvi the trip odometer is very close to what the trip odometer on the ATV.

The differences are within the accuracy of one mile in a 50 mile ride. And several GPSr are all within 2% of the group.

[Boyd]

Yes... but try walking around with it...

[LIHIKER]

if you look at Oregon's wiki, there is a whole discussion about the inaccuracy of the trip odometer. Here is the link. http://garminoregon.wikispaces.com/message/view/home/20457151

[schandler]

wow, i thought i was just asking a dumb question. Now i see that this has been a complicated, confusing issue that has not been consistently resolved between units. Regarding speed issue, i will take the unit out on my ocean kayak where we travel at around 3mile/hours  and clear line of site and of course flat terrain. Curious if my known distance and stopped time are correct.

You would think that garmin is aware of this and would have a firmware update.

thx again for your thoughtful responses!
scott

[alpine]

Yes... but try walking around with it...

At my age walking is very limited. A knee replacement and hip replacement will do that for ya.

[Boyd]

Sorry to hear about that. But the OP was asking about the accuracy of the odometer when hiking.

[alpine]

I don't see the significance between modes of locomotion. Except of course the sample rate/over the distance traveled.

Sample rate on tracks from an ATV vary between 5 feet and 150 feet apart (speed dependent of course).

Other variables on sample rate would be loss of signal causing fewer sample points.

So what would make walking different from other modes of movement?

[Boyd]

If you want to assume that a nuvi on a moving vehicle gives the same results as a handheld at walking speed, that is certainly your privilege. But it sure doesn't match my personal experience and I couldn't believe it without seeing some real world tests.

[-Oz-]

How much is it off by?  I noticed it my 60csx was never off by very much.  Haven't cared enough to test the Dakota.

[schandler]

on my dakaota walking in hill/mountains that fluctuates between canopy and open sky, distance and time travelling data can fluctuate by as much as 50% compared to original track/route.  When on flat open ground, it is very accurate.

thx
scott

[Seldom]

You might try updating your firmware.  My OR300 odometer was as you describe above until I installed 3.81 Beta.  Trip computer indicated about 50% stopped time when walking under canopy. Now it is much more accurate.

[-Oz-]

Alright; so I can now say (not sure if I have the latest firmware) that the dakota odometer sucks!

In a 3.5mi part of the hike (switchbacks up a mountain) the trip odometer only recorded 2.4.  And it just continued like that.  I'll have to see if there's an update and try again but this is pretty much a deal breaker for me and I'll just go back to my 60csx.