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activityworkshop / GpsPrune

GpsPrune is a map-based application for viewing, editing and converting coordinate data from GPS systems.
GNU General Public License v2.0
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Loading STRM heights does not work properly #53

Open snooppr opened 2 years ago

snooppr commented 2 years ago
  1. I used my NASA account without it. However, the heights are not loading (just an infinite wait).

Reproduce the problem: download the attached track (because it is in this area that there are problems with loading heights); remove height field value and upload heights online (I also used vpn different locations didn't help).

Used versions with the problem (v21.2 and 21.3); GNU/Linux/deb.

1

  1. If the .gpx track contains all the heights, why is gpsprune constantly trying to load them online before rendering to 3d? Considering point 1. I cannot build 3d, forever loading heights in this area (besides, I wanted to build 3d pointing out a completely different significant problem when generating the povray file).

gps track

activityworkshop commented 2 years ago

Hi, thanks for the bug report.

There are a few things going on here, some of which are GpsPrune's fault. Firstly, the region you're looking at is between 61 and 62 degrees north. SRTM data only goes up to 60 degrees north (see https://www.opentopodata.org/datasets/srtm/ for a picture of the data coverage). This is not because of GpsPrune, it's a consequence of the orbit of the data collector. There's not a lot GpsPrune can do about this, the SRTM data just isn't available. It could be that somewhere there is a suitable, accurate, freely-available set of elevation data which is not from SRTM and which does cover this part of Finland, but if there is then I don't know about it.

Secondly, GpsPrune doesn't deal very well with the data being out of range and doesn't show a good error message to explain what happened. This can and should be fixed, most likely with version 22. Thirdly, this should have been tested properly but for some reason wasn't, so I apologise for that.

If the .gpx track contains all the heights, why is gpsprune constantly trying to load them online before rendering to 3d?

If you don't want to see the terrain, then GpsPrune won't try to load the SRTM data. But if you ask it to show the terrain as well, then it needs to get the elevation data from somewhere ;)

snooppr commented 2 years ago

Graphoper builds a track and displays the heights, this is the track: https://graphhopper.com/maps/?point=61.93385%2029.02736&point=61.91684%2029.01240&locale=ru-RU&elevation=true&profile=foot&use_miles=false&selected_detail=Elevation&layer=Omniscale

Screenshot_20220621-204716_DuckDuckGo

In addition, osmand also offers to download the 500mb bump/shading map of Finland.

As for the height issue with 3d, I'm in a hurry. Sorry. There are point heights for the track that you are loading and there are location heights for rendering it in 3d.

activityworkshop commented 2 years ago

That tells me that Graphhopper has access to elevation data for Finland, and OsmAnd has access to elevation data for Finland. That's good news, but it doesn't help you if you're in a hurry.

GpsPrune uses SRTM data for its elevation lookup, and SRTM data isn't available for this part of Finland. Longer term it may be possible for GpsPrune to use the same elevation data as Graphhopper and OsmAnd, but that's longer term. I will try to find out where their data comes from.

Again, GpsPrune can show the track in 3d without elevation data, but if you ask for terrain then it needs elevation data.