MegaSack DRAW - This year's winner is user - rgwb
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Hi,
I have captured a number of routes with my Garmin GPS but find the altitude data a bit hit and miss and am trying to find a way of sourcing accurate altitude data for the captured lat/long coordinates. I have downloaded memory map which does seem to have altitude data which is not affected by atmospheric pressure, so will be more accurate than my 305 data. What I want to know before I buy the software is whether I can import a garmin GPS file into memory map and then export it again but with the replaced altitude data ?
Thanks
Can you upload it to garmin connect - as they will do an altitude adjustment on your route bottom left of the page and you can see how hit and miss it is?
You can export the tracklog if you convert it to a route then it will re-adjust your altitude?
Thanks. I have not tried that. I will give it a shot now
The problem with Memory Map (and other mapping programs) is that the elevation data isn't very accurate. It's derived from "spot heights" about 50M apart and is then interpolated.
Druidh - Yup but at least he'll know if his recorded altitude is similar or way out?
I'd always go with the Garmin recorded figure - assuming it's been calibrated at some point fairly recently.
I have just spoken with Memory Map and they have confirmed that you cannot export their altitude data. That is a shame as the altitude data is based on the contour lines of the OS maps, which will be smoother than what the garmin captures. The garmin samples every second and over 5 or 6 seconds the altitude fluctuates. I am just looking for a smoother data set.
I have an algorithm for smoothing the captured altitude, but it is still not great.
I was hoping there would be a free SOAP service some where on the net for obtaining height data, but I cannot find one
I'd always go with the Garmin recorded figure
My Edge 705 elevation data usually goes tits up if I go out riding in the rain (unless I put a plastic bag over the 705, then I can't see the display), its due the the barometric sensor holes getting blocked by the water.