Offer high-resolution LIDAR elevation data

Guest shared this idea 4 years ago
Gathering feedback

Right now Locus offers 3" arcseconds (= 60x90 meter) meshed elevation files to download for calculating elevation statistics of hiking tracks or displaying dynamic elevations at the cursor's location.

My proposal is that Locus could also offer the high-resolution version of elevation files to download: 1" (= 20x30 meter). Best suited for European LIDAR files from here: https://forum.locusmap.eu/index.php?topic=5363 but also for the rest of the world there is a 1"-version of SRTM data available since some years.

Especially in alpine or hilly terrain it can be siginificant different on calculation a track's altitude gains or dynamic elevation if using rough 3" or fine-meshed 1" elevation files. Locus could offer both versions to choose from, the 3"-version if people run short of phone's memory or slow internet connection.

Of course people are already able to manually download the 1" files and install it within Locus themselves. But this is far less convinent than being automatically downloaded/installed within Locus. And most of the Locus-users don't even know that Locus "just" provides 3" data and finer meshed data files would exist too.

Replies (4)

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Hi sonny,

thank you for the idea and also for you excellent and precise data. Honestly we already thought about 1'' data files. We'd like to offer them in Locus but we haven't decided the optimal implementation (because the size, traffic, storage, etc). But we support this idea.

Thank you, Petr

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I highly support the request for builtin support of 1" resolution elevation. For .hgt files, and also for contour lines in LoMaps. In fact, LoMaps seem to even use much lower resolution altitude data to generate contour lines, as you can see in the attached screenshot. The left screenshot uses an OpenAndroMaps map with 1" .hgt, the right one (same location) uses a LoMaps map with 3" .hgt; and in the right, you see that contour lines cross the ridge, at west of the peak l'Étale, although hill shading is already largely inaccurate compared to the first one. These LoMaps maps look pretty, but are useless for mountain activities.

Also, I would suggest to store .hgt files in a compressed format (bzip2 seems the most compact, yet still fast to decompress). Especially as Locus already supports 0.5" or 0.25" resolution, but then uncompressed .hgt files are really large! This resolution can be necessary for precise and reliable slope coloration, very important for ski-touring and avalanche avoidance.

Thanks!

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I would go even further and ask for support for DEM data of arbitrary precision :-). For Slovakia we have free DEM data with 1m/px resolution (similar goes for Poland, Slovenia...). Ideally if Locus could understand GeoTIFF format with a single grayscale band and use it also for hill shading.

It would be also nice if such files would be downloadable and recognized by locus-actions provider protocol.

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@Martin Thank you for your contribution. I'm sorry, but the implementation of GeoTIFF support task is quite a complex task that we can't focus on right now. Perhaps someone in the community would be able to prepare .hgt elevation data at a more detailed resolution. The application should work with all HGT files, for example also with the 0.3 arc second grid.

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