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#1 2021-12-27 18:57:42

lucabert
Member
From: Dresden
Registered: 2020-11-23
Posts: 78

Getting elevation by coordinates

Hi!

I'm writing an Android App (using Java and OSMDroid) to fly VFR.
I rendered the maps using an own tiles server and the data from OpenStreetMaps in order to have a style very similar to the ICAO maps.
It works.

Now I'd like to add a function in my App to display a vertical profile of the route. Unfortunately I didn't found any function to get this information.
I think, OSM does not have the elevation of a point, too, so OSMDroid cannot give me an information it does not have...

Very important: my App must work completly offline, since in the airplane I don't have an Internet connection!
Can some suggest me a way to solve my problem? I don't need a huge precision, but I do need a relative small file to import in the App...
I think the max elevation in a square 2x2 km (or maybe even 5x5 km) is enough.

Thank you very much for your suggestion
Luca

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#2 2021-12-28 08:09:31

PHerison
Member
From: Rhein-Main
Registered: 2008-04-04
Posts: 1,769

Re: Getting elevation by coordinates

Besides the ele-Tag (https://wiki.openstreetmap.org/wiki/Key:ele) OSM has no information about hight above sealevel. Most applications uses SRTM-Data (https://en.wikipedia.org/wiki/Shuttle_R … hy_Mission).
[edit: Typos]

Last edited by PHerison (2021-12-28 08:11:59)

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#3 2021-12-28 22:10:34

Viajero Perdido
Member
Registered: 2016-10-13
Posts: 193

Re: Getting elevation by coordinates

Have a close look at http://www.viewfinderpanoramas.org/dem3.html (link #16 from the wiki article).  This is basically the SRTM data set with regional improvements.

The map app I use (Locus) uses HGT files from that source to implement vertical route profiles and slope shading.  The files appear to each cover 1 degree by 1 degree, and are typically 2.8MB in size.

The ele tag is used infrequently in OSM (mostly for peaks and saddles), and - in my own region at least - is occasionally quite inaccurate.  I wouldn't rely on it for aviation safety!

Last edited by Viajero Perdido (2021-12-28 22:22:27)

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