## Elevation gain

Started by Cory McAlpin, November 06, 2016, 01:03:24

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#### Cory McAlpin

Why does locus pro not display elevation gain after a recorded ride? All I can find is minimum and maximum elevation.  How would I calculate?  As it is now I have to wait till I get home to upload to Strava to see my elevation gain on Strava.
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#### michaelbechtold

You can configure the tracking side panel.  Long tap an item and go from there.

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#### Cory McAlpin

Thanks for the info! I just discovered, thanks to your tips, that I can now look at what percent grade I am climbing and my current speed. Previously only my riding friends who have newer Garmin devices could alert the group on those stats. Now I can see as well!
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#### Cory McAlpin

Well even after the initial replies to this topic, and after I added all the elevation fields to my side panel, I guess my question seems to remain un answered. I may not fully understand elevation gain but what I do know is on Strava, after I export a ride to Strava, it lists my distance as well as elevation gain. This is a very important field for me as distance plus elevation gain equals ride difficulty. Kind of a bragging right. But even with all the elevation values that Locus pro offers, I don't see anywhere that is listed as "elevation gain". I see elevation (downhill), elevation (uphill), min. altitude, and max altitude. I am sure there is a simple mathematical formula to calculate elevation gain and that Strava does this automatically for me. So 2 questions here and sorry for appearing so ignorant:
1: Am I missing something? Is there a field for elevation gain on Locus Pro?   AND
2: If not How can I calculate my elevation gain from the values that locus Pro displays
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#### Christian

Elevation gain = elevation (uphill)
IMHO
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#### Cory McAlpin

#6
Quote from: Christian on November 20, 2016, 22:20:34
Elevation gain = elevation (uphill)
IMHO

Is it really that simple? What about the negative elevation like elevation downhill? Yesterdays ride says my elevation uphill is 1739 ft. That same ride displayed on Strava is listing 1139 ft of elevation gain. It doesn't add up.
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#### michaelbechtold

Elevation collected from GPS in mobile devices is like rolling the dice around the true curve.
This adds to both, uphill and downhill count.
When I am interested in elevation stats, I first run the track through the "fill elevation" task (edit-more-fill elevation in track screen). You will see the changes easily in your examples. And both should be pretty close afterwards.
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#### Cory McAlpin

Quote from: michaelbechtold on November 20, 2016, 22:42:07
Elevation collected from GPS in mobile devices is like rolling the dice around the true curve.
This adds to both, uphill and downhill count.
When I am interested in elevation stats, I first run the track through the "fill elevation" task (edit-more-fill elevation in track screen). You will see the changes easily in your examples. And both should be pretty close afterwards.

Man Michael, you completely lost me in the last 3 sentences.........
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#### Cory McAlpin

#9
Ok Michael I figured out what you mean. And I see once I select "fill elevation", and it does the process, the min and max elevation changes. But can you elaborate, in simpler terms, what I just did by doing this? Even though the stats changed afterwards, I still don't get an answer to "what is my elevation gain for this ride" without having to look at my strava upload. Does this mean that all my past uploads to Strava from Locus pro, since I didn't do the fill elevation task, are inaccurate?

If you are saying the elevation uphill= elevation gain= simple enough. After filling elevation, it is closer to Strava but still a few hundred feet higher than Strava says.

Here's an interesting one though......A few weeks ago we went on a ride on a flat trail for 40 miles. There may have been a 1 percent grade at times but it was basically a flat old railway track turned into a hiking, biking trail. Even after filling elevation just now on that track, it still says 1168 feet of elevation uphill when strava says a much more realistic figure of 244 feet of gain.
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#### michaelbechtold

OK. Fill elevation is one of the functions for a completed track. This does substitute the GPS elevation by data from SRTM files that are stored on your device or read via internet. Those SRTM data from satellite screening are not jumping up and down like crazy. This is why your elevation ups and downs will come down. And such happens for all tracks you adjust via fill elevation. If the tracks ate bear to each other, then the total up and down hill will be near to each other, too. Makes sense ?

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#### Cory McAlpin

#11
Quote from: michaelbechtold on November 21, 2016, 00:13:29
OK. Fill elevation is one of the functions for a completed track. This does substitute the GPS elevation by data from SRTM files that are stored on your device or read via internet. Those SRTM data from satellite screening are not jumping up and down like crazy. This is why your elevation ups and downs will come down. And such happens for all tracks you adjust via fill elevation. If the tracks ate bear to each other, then the total up and down hill will be near to each other, too. Makes sense ?

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Yes it does sort of. I had read about elevation (in general online) in that there is the actual elevation your device reads and then there is elevation values calculated from satellite maps. The older Garmin devices did not have baro sensors and thus used map data to calculate elevation based on where you rode or hiked. Everyone has always said barometric values (from better garmins) were much more accurate than their predecessors. My Galaxy s5 has baro sensors so wouldn't it's actual calculated elevation be more accurate than SRTM files,assuming those files are the same values from satellite maps?  It sounds like your are saying SRTM files are just that; map elevation data. So am I mislead about which values are more accurate?

Also can you explain why a ride I did on a very flat rail trail, calculated over 1000 feet of elevation UPHILL on Locus when Strava said it was 244? 244 feet is more accurate. There was no climbing on that ride. Other than that, the other tracks recorded in locus are within a couple hundred feet or less than the elevation gain that strava recalculates it to. Why does Strava change your values. If I have 1469 feet of elevation uphill on locus, from another ride, why did Strava change it to 1139 feet of elevation gain?
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#### michaelbechtold

Copy those tracks in Locus and use Fill Elevation on the copy then compare new value with Strava. The 'dice' I called the mobile GPS is turning a flat course into ups and downs. Fill elevation removes such effect.
In general Baro can help,  but I am not a specialist in this area. There has been a lenghty discussion in Locus Forum. Maybe you do a search for elevation ...

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#### lor74cas

I do not have a pressure sensor so when I found that altitude data of the recorded track with just gps are crazy I tried to solve.

First you need a good accuracy of recorded track points:
settings -> track rec -> choose your profile settings --> requested accuracy set a strict value (for me 30mt)

Second you can have better SRTM values using HGT files with 1" arc insted of 3"
http://help.locusmap.eu/topic/hgt-elevation-data-display-if-both-1%E2%80%9D-and-3%E2%80%9D-resolution-hgt-files-are-present-in-the-srtm-directory
http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org1.htm
http://www.viewfinderpanoramas.org/dem3.html

and if you want a costant application of srtm data and bypass the "fill data.." after track recorded use this:
in settings -> gps and position -> altitude manager -> settings -> srtm data -> replace gps values

Locus Map 4
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#### Cory McAlpin

Quote from: lor74cas on November 21, 2016, 12:43:28

I do not have a pressure sensor so when I found that altitude data of the recorded track with just gps are crazy I tried to solve.

First you need a good accuracy of recorded track points:
settings -> track rec -> choose your profile settings --> requested accuracy set a strict value (for me 30mt)

Second you can have better SRTM values using HGT files with 1" arc insted of 3"
http://help.locusmap.eu/topic/hgt-elevation-data-display-if-both-1%E2%80%9D-and-3%E2%80%9D-resolution-hgt-files-are-present-in-the-srtm-directory
http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org1.htm
http://www.viewfinderpanoramas.org/dem3.html

and if you want a costant application of srtm data and bypass the "fill data.." after track recorded use this:
in settings -> gps and position -> altitude manager -> settings -> srtm data -> replace gps values

Does this stuff you are telling me apply to me since I have a baro sensor or just to someone who is using a device WITHOUT a baro sensor? I hate to just start changing values i do not understand if it is going to make it worse for my particular phone. With a baro sensor do I still want to bypass the fill data and replace gps track values or is this just what you did because of the device you were using with no baro sensor?
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