GPX recording apps like Locus are great for hikers. They use GPS receivers in a phone to locate us on a good vector map downloaded and stored off-line and even allow to record the hike. After the trip they show a summary of the recorded track – usually the data like distance, average speed or elevation gain.
The estimation of the elevation gain is unfortunately often very imprecise. The GPS receiver can be off by around ten meters to either side and throught the day the differences coming from this imprecision can add-up to gigantic numbers. The apps like Locus try to solve the issue by apllying some smoothing to the altitude profile of the track, which is a generic way to treat data, not really helpful for this particular task.
A human with a map in hand is usually better at estimating the altitude gain of a path then the apps. Our trips usually consist of a small number of peaks that are easy to identify. We can also find the lowest points between these peaks and sum the altitude differences.
The same thing could also be done by the app, if it only could read the map. Unfortunately, the map is just a picture, the app does not really understand it. We could however help the app by telling it how many peaks there were in the trip. The app should be able to find these peaks in the track profile.
That is essentially what our app is doing. We tell it to find peak after peak and it should find them. Once the peak is identified, it is shown on the map, in the new (estimated) profile, and counted in to the elevation gain estimation.
The track must be in GPX and only contain one path.
By clicking the Add peak button, we invoke a search. The new peak will be
immediately presented on the map.
Sometimes we might not agree with a peak that the app thinks it found in the
track profile. By clicking in the marker and Delete button, we can remove the
peak.
If the app is not able to find the peak, that we can see ourselves, the sliders allow us to limit the part of the track where the search should be performed.