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[Feature Request] Filter: remove points above/below the specified speed #84

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snooppr opened this issue Aug 27, 2023 · 2 comments
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@snooppr
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snooppr commented Aug 27, 2023

Track --> compress track (there are filters to remove crazy points), but it does not allow you to do the most popular operations: remove all points from the track, the speed of which is higher than 51 km / h, for example. Rationale, if I ride a bike, then I know that my speed could not be more than 90 km/h. or less than 5km/h. 5km/h and 90km/h are GPS emissions, these points need to be destroyed (this is a very popular operation among users). Or, for example, I'm going on a hike, due to gps-emissions that happen on any device, crazy dots appear at a speed, for example, 39 km/h, and so on. On the march, I know that any points over 7km/h are not true and must be destroyed. Otherwise, when you upload a track to any sports social network, third-party users, seeing the maximum speed, think that you were given a ride in a car or there was a break in the gps signal, etc., it’s unpleasant.

A workaround is to use the gpx track editor software and its filter (specify maximum speed from the track.gpx for the range of which all points will be deleted).
gpx track editor

@activityworkshop
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I haven't got any accurate figures on which functions are "the most popular operations", or which are "very popular operation among users" - GpsPrune users are as you know very diverse and use GpsPrune for all kinds of different things.

The possibility to compress the track according to speed is already listed on the development page as planned for version 24:

New compression method based on speed?

so it sounds like you're just agreeing with that.

Having said that, there are some problems with this, which need to be resolved:

  • it is very possible to cycle at less than 5 km/h, so I don't want to delete any points here. Maybe I'm stopping to check the route, maybe I'm stopped at the traffic lights, and then I don't want any points to be deleted at all. Maybe I want a segment break, but that's not what the track compression does.
  • I can also cycle faster than 51 km/h (downhill) and I definitely don't want any points to be deleted in this case either. Those points are fine and I want to keep them

I also have to distinguish between two different causes of high speeds. Maybe the high speed is real (I'm actually in a car), but then deleting one point doesn't change the speeds of the neighbouring points. A second possibility is that just one point was measured incorrectly, which gives a high speed away from the actual position and then a high speed back again. In this case, deleting one wayward point changes all the speeds to be more reasonable.

Before you upload your track to any "sports social network", it's easy to check the speeds by right-clicking on the altitude diagram and switching it to show speeds. This should tell you whether you've also included the car ride by accident or not.

@snooppr
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snooppr commented Aug 27, 2023

5/51 km/h were chosen randomly, no need to be attached to them, this is a custom filter, the user sets the boundaries himself. For example, look at how they do it in different applications, for example, the speed / distance filter in osmand is simply amazing.
osmand

I haven't got any accurate figures on which functions are "the most popular operations", or which are "very popular operation among users"

In this case, I recommend creating a survey (it's simple and works, for example, Google forms, etc.) by function and identify popularity.

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