Does the route/track show Ascent/Descent or Elevation Gain/Loss?
Answered
I have a question that bothers me to effectively plan a route. Does the route show actual ascent/descent or just elevation gain/loss?
As illustrated below, the ascent for this hike from A to G is 15m (5+2+5+3), whereas the elevation gain is only 9m (5+4). Similarly, the descent between C and F is 6m (-4-2), whereas elevation loss from A to G is still zero.
- If the route shows only the elevation gain, it's not that useful for planning a hike for the day, because its the ascent that would determine the effort I will have put in for a hike. As the ascent is additive, it will also affect the time required for the hike.
- I know the track currently shows only elevation gain & loss - although it incorrectly mentions it as Ascent & Descent in the track profile - because at the end of a day's hike when your return to the trailhead, the gain and loss are practically the same, exactly what would happen if you were to hike up from A to G and then back down to A in the above illustration.
Although I am categorizing this as an iOS Feature request, this applies to all platform because it relates to how the hike data is collated and presented for routing and track.
-
Unfortunately, this is not what I am getting. Please have a look iPhone screenshot of a track that I am sharing. A section of the track is a steep ramp, with an approx 30m descent.
When I did 5 roundtrips of this ramp section on a given day, it should have given me a total ascent & descent in the range of 150m (5 x 30m) and up. However, on my iPhone, it gives me an ascent/descent of 39m(-38m), which is way too different from 150m that I was expecting. And I have gotten similar results with other tracks too for the hikes have done in the past. On the other hand, my other app (Cyclemeter) that I ran along with GAIA reports a result of 157m(-154m) closer to the expected result.
BTW - for the same track - see link below - GAIAgps.com reports yet another result 45m (-46m), which is different from iPhone results - and hence, this is topic for another discussion.https://www.gaiagps.com/datasummary/track/6ddc704726de991c9bff093ff5df87d6/
-
The stats for your track/route should report cumulative elevation gain and not the difference between the stating and highest elevation.
Would you mind sending a link to the track/route in question to support@gaiagps.com so we can take a closer look at this issue? -
Hello, I seems this issue may still not be resolved. My I-Phone and the track on the computer show only difference between starting elevation and max elevation, not cumulative elevation gain like is shown by AllTrails. Can you address this question, please? Is there a setting that one can change? This is my latest track: https://www.gaiagps.com/datasummary/track/07ad6936aef5828f6cb05d7fea40c821/?layer=GaiaTopoRasterFeet
-
Hey @freizeitreiter,
The ascent value is the sum of all feet climbed, the descent is the sum of all feet descended. If you climb 10 feet, descend 10 feet, then climb 20 feet, your total would look like: +30/-10.
It looks like the ascent and descent are being properly calculated in the track that you shared.
If you have any further questions, please contact Support here. -
Here is a much better example: https://www.gaiagps.com/map/?loc=13.9/-106.2763/35.8922&pubLink=LbfAIPIhnB7bhW0NSO1TiK78&trackId=08400434a6d510112b0ea42585217ebf
Just by eye, the net gain of the 4 climbs should add up to at least 350+350+160+400 = 1260 feet.
See below, Gaia reports 819 ft ascent. See farther below, if I export the track and load it into Google Earth it reports 1349 ft of elevation gain (sorry, the font is probably too small to read). That number looks good if you look closer at the details. This is not an unusual example with Gaia.
I do a lot of backcountry exploring and love Gaia. But I would really like to see a fix for this issue. If you poke around these help pages, you can see it reported many times.
Thanks, Mike.
-
I have found the same issue that michael.b.prime and other are seeing. Gaia seems to always show elevation gain/ascent that is 15-30% (estimating) less than the actual elevation gain. I have compared with known elevation gain from other's recordings or reports, with other applications on friend's phones on the same hike, and even just looking at a topo and doing some math. Gaia always reports substantially lower elevation gain than any of the other sources.
I have not tried exporting any of my tracks to Google Maps like michael.b.prime mentions but that's an excellent idea. I'll feel better about the hikes where someone else's report says 3400 ft of ascent and I only recorded 2800 :)
There definitely appear to be a bug of some sort in the algorithm that is generating the ascent values. I'm with Mike that I would love to see this fixed up by Gaia. Thanks.
-
It's been crickets on any reply or action.
I am an engineer. I try not to tell other tech people what to do, but since nobody at Gaia is replying, I will. The way the altitude measurement works, the rae data needs some smoothing before you calculate ascent or descent, or you will overcount. My guess is they are smoothing over a certain number of measurements or a certain length of time. If you are moving quickly enough, that rounds off the peak and valleys and your ascent is under calculated. If you change and smooth over fewer points, and someone is moving slowly, you probably get the opposite.
I would think that smoothing over a certain distance travelled, rather than time or number of points, would get you closer to an optimal solution.
It's a guess. I could be totally wrong.
-
Hey @Rebecca,
Michael is right that we use an algorithm to process the raw GPS data.
When recording tracks, the app is fed all the raw location data gathered by the GPS chip on your device. From there, the algorithm filters out inaccurate points, and then averages the GPS points in groups, and then adjusts the ascent/descent number as you travel. It is likely that other apps use a similar but different algorithm, so this might be part of the reason for discrepancies.- GPS Visualizer has a more detailed explanation of GPS data sampling if you are interested: https://www.gpsvisualizer.com/tutorials/elevation_gain.html
- This article discusses some other reasons why you may see a discrepancy in recorded tracks: Why GPS Track Recording Can Be Inaccurate
If you have additional questions, would you mind sending a link to one of your tracks here so we can take a closer look at this issue?
Post is closed for comments.
Comments
15 comments