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Accurate AEG from a GPX file?

Posted: Jun 07 2009 6:46 pm
by azdesertfather
Does anyone know if there is a website or any software that can take a Garmin GPX track, read the data coordinates to determine the accurate elevation for each point, so that you can end out with a more accurate AEG? I understand that TOPO! does that, does any other software? Can Google Earth do it somehow?

Re: Accurate AEG from a GPX file?

Posted: Jun 07 2009 6:59 pm
by joebartels
no, you have to plot it on a real map with elevation data to get rid of the errors
TOPO! works best and is worth the money

Re: Accurate AEG from a GPX file?

Posted: Jun 07 2009 7:10 pm
by big_load
joe bartels wrote:no, you have to plot it on a real map with elevation data to get rid of the errors
TOPO! works best and is worth the money
I agree. It's even worse than using GPS tracks to estimate mileage (correcting on a map, I find the recorded GPS mileage up to 10% short because it cuts corners between sampe points).

Re: Accurate AEG from a GPX file?

Posted: Jun 07 2009 7:42 pm
by ---
Yeah, what they said...

Re: Accurate AEG from a GPX file?

Posted: Jun 07 2009 7:59 pm
by azdesertfather
Will Garmin's Topo US 24K map software for AZ/NM do the same thing? Does it have this functionality?

Re: Accurate AEG from a GPX file?

Posted: Jun 07 2009 9:08 pm
by Grasshopper
dshillis wrote:Will Garmin's Topo US 24K map software for AZ/NM do the same thing? Does it have this functionality?
Think you are referring to the Garmin MapSource US Topo 2008 Software: I have it and use it along with the Natl Geog. TOPO! Software (which I like best). For me the Garmin Software is easier to upload GPS Routes on HAZ. The Garmin Software does a profile of the hike like TOPO!, but only provides the hike mileage and not an AEG calculation like TOPO! does. The Garmin profile does allow you to show all the track points on the hike profile and you can click-on any track point to get mileage and elevation for that point, but you would have to do the calculations for AEG manually. The Natl Geog. TOPO! is really nice and also allows you to do a 3D tour of you hike track which is kind-of cool. New, it's worth the ~$90+ investment if you enjoy saving and reviewing all your tracks in more detail. I did tried to copy a sampe hike profile of mine from my Garmin MapSource, but it won't allow me to copy that page to attach here.

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 8:38 am
by Jeffshadows
Depending on how accurate you want the results to be, you would either have to use a map as Joe suggested or one of the extensions in ArcGIS or GRASS. Contact the National Geospatial Intelligence Agency and demand that they do it for you since you're paying their salaries with your taxes :D

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 8:41 am
by azdesertfather
Jeff MacE wrote:one of the extensions in ArcGIS or GRASS
??

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 8:43 am
by Jeffshadows
dshillis wrote:
Jeff MacE wrote:one of the extensions in ArcGIS or GRASS
??
Software used by pros to make maps and/or manipulate geospatial data. The easiest way to do what you're asking is run your finger across a good, old-fashioned topo.

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 9:56 am
by joebartels
Use TOPO! it's cheap, easy to understand and works.

ArcGIS is the mother of all power, yet better if you're plotting huge amounts of data like lakes for the entire US. It's extremely difficult to understand without studying or training. Not to mention corporate pricey unless you know command line unix.

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 10:30 am
by Jeffshadows
joe bartels wrote:Use TOPO! it's cheap, easy to understand and works.

ArcGIS is the mother of all power, yet better if you're plotting huge amounts of data like lakes for the entire US. It's extremely difficult to understand without studying or training. Not to mention corporate pricey unless you know command line unix.
Indeed.

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 10:49 am
by BobP
Has any one used NG topo explorer/or deluxe?

Is that the NG your talking about - Grasshopper?

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 11:21 am
by Grasshopper
rlrjamy wrote:Is that the NG your talking about - Grasshopper?
No, mine is the standard NG TOPO! 4.0 version for AZ only (they sell the states seperately for ~$90.+);
I believe the upgraded version you refer too might be one that chumley is familiar with.. I recall a past thread on this subject where he was active.

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 11:41 am
by BobP
Thanks!

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 2:19 pm
by azdesertfather
rlrjamy wrote:Has any one used NG topo explorer/or deluxe?
What's the difference?

Re: Accurate AEG from a GPX file?

Posted: Jun 08 2009 2:25 pm
by BobP
$25 and a seamless, nationwide, set of USGS 1:100,000 scale topographic maps.

That is between explorer and deluxe.

This is the link Grasshopper was referring to:
http://www.hikearizona.com/dex2/viewtop ... rer#p28631

Re: Accurate AEG from a GPX file?

Posted: Jun 15 2009 9:42 pm
by azdesertfather
Hey, I have found a free solution for the Mac, until I buy NatGeo Topo!

TrailRunner ... it seems to be pulling in Google data and determining AEG for you. Anyone else use it? Am I right?
http://www.trailrunnerx.com

I've already adjusted down several of my AEG's from recent months. How frustrating that my Garmin is so way off on lots of these!

Re: Accurate AEG from a GPX file?

Posted: Jun 15 2009 9:47 pm
by joebartels
I can't tell because I would never pay for a unix based system like a MAC when unix is FREE! Anyhow I don't know for sure but I don't think it has NED data. However under FAQs it does mention inadvertently that when you merge a route to the map it adjust it to pre-configured data. The GPSies.com uses elevation data so maybe.

A free solution that finds NED data for each lat/lon coordinate of an uploaded route is at http://www.latlontoelevation.com/ However it's slow, tedious and if I recall it produces a comma separated values file. Of course you can convert that to GPX via GPSBabel. It's not streamlined or a map interface like the above but I guarantee it does not manipulate your data.