Reverse path Elevation gain.

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PLEASE search for previous similar feature requests before filing one.

Please describe what your requested feature would do, how it would work,
etc:

I'd like to be able to get the elevation gain of a path in reverse as well as 
forward. That way if I only record one direction of an out-and-back trip, I can 
get the total elevation gain, as well as the total distance.

I went on a 4 day backpacking trip with an N1 and a spare battery. With 
everything except GPS turned off, I still didn't have enough power to record 
every hike, but I did have enough to cover every path I took in at least one 
direction.

It seems like it would be an easy feature to add.

Original issue reported on code.google.com by dghartm...@google.com on 23 Jul 2010 at 1:11

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I'm not sure I understand what you're asking for - if you took the same path, 
the elevation gain and distance should be the same, shouldn't it?

Original comment by rdama...@google.com on 25 Aug 2010 at 2:01

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I had to talk to Dan to understand the request.  It is not the same if your 
track is one way.  The reverse can have a very different elevation gain. [Think 
climb to the top of a mtn then stop.]  I believe he found the answer he was 
looking for by working with the csv file.

Original comment by sandordo...@google.com on 25 Aug 2010 at 4:00

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Does that mean this is no longer a request for us?

Original comment by rdama...@google.com on 25 Aug 2010 at 5:51

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While it is possible to get this data manually, by dumping the CSV and running 
a low pass filter on the points in verse order myself, you could say the same 
about elevation change in the forward direction. I'd like to keep this as a 
feature request, but I'd understand if you deprioritized or removed it

Original comment by dghartm...@google.com on 25 Aug 2010 at 6:24

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Original comment by sandordo...@google.com on 24 Sep 2010 at 11:18

• Added labels: Priority-Low, Work-Medium

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Original comment by sandordo...@google.com on 6 Jan 2011 at 4:50

• Added labels: Priority-VeryLow

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I believe what you are asking for is called "elevation loss".  When you walk 
from A to B and My Tracks gives you the elevation gain (let's call it Eg_AB).  
You wanted to know the elevation gain you would have gotten on your return walk 
from B to A (let's call it Eg_BA).  Well the developers don't need to do any 
effort to tabulate and display that since there is an easy to understand 
equation that relates these two elevation gains to the altitudes of A and B 
(let's call then Alt_A and Alt_B).  The formula is:

Alt_B - Alt_A = Eg_AB - Eg_BA

If you think about it a bit, I am sure you can convince yourself this is true.  
If you are not convinced this is correct, say so and I will try to give a 
better explanation.

So you can solve that equation for Eg_BA:

Eg_BA = EgAB - Alt_B + Alt_A

I have done this experiment by recording a path and it's reverse and these 
numbers agree with the My Tracks results as much as can be expected by the 
jitter in elevation data from GPS.

So I would suggest the developers close this issue...

Original comment by fbh1...@gmail.com on 15 Sep 2011 at 3:30

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Well done. I agree.

Original comment by dghartm...@google.com on 19 Sep 2011 at 5:01

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Original comment by sandordo...@google.com on 19 Sep 2011 at 5:04

• Changed state: WontFix