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Offline Elevation Data

Nick Suter shared this question 7 years ago
Answered

I have previously downloaded & used without issue 1 arc-second (30m) SRTM HGT files. Stored in Locus/data/srtm


For NZ, there are higher resoltuons (8m) available here:

https://data.linz.govt.nz/layer/1768-nz-8m-digital-elevation-model-2012/

It looks to be in GeoTiff format. Do I need to convert them to HGT for use in Locus?

Will locus handle this resolution, before I bother any further?

Replies (4)

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Dear Nick,

honestly we haven't tried hgt data in such resolution, but Locus should very likely handle it properly. However the best solution is to give a try.

Please convert geoTiff into HGT file, try it in Locus. Send me the converted HGT file in case of any issue. We'll fix it.

EDIT: please email also if it'll be succesfull

Thank you

Best regards

Petr

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I used GDAL_TRANSLATE and created a HGT file (had to zip to attach).

I have altitude manager -> settings -> SRTM DATA set to Replace.


This is the area:

http://www.topomap.co.nz/NZTopoMap?v=2&ll=-42.874571,171.775001&z=13


I can't really tell if Locus is using my HGT file or not. I removed the already existing locus file from locus/data/srtm and then put my file in there. I get altitudes shown at the cross hair (and a complaint that the Geoid model is missing).


Also, when moving the map, I have to wait 2 seconds after stopping for the altitude to appear.

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No, its not working. I replaced it with the proper S43E172 from USGS:

https://e4ftl01.cr.usgs.gov//MODV6_Dal_D/SRTM/SRTMGL1.003/2000.02.11/S43E172.SRTMGL1.hgt.zip


and that one works (it displays the altitude immediately).

Possibly my converted file was bad.


I also read in a comment somewhere that HGT is only accurate to 1 arc-second anyway (can't confirm).

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Hello Nick,


the is probably some issue in conversion. I've tried to display your hgt file in qGIS. qGIS loads the file but the data are probably moved. See attached image that shows the Lake Sumner. There are some peaks in the middle of the lake according to hgt file.

Locus partially loads it (see another screenshot) but it isn't definitely correct. I'll discuss it with the main developer.


Please let me know if you're able to convert file successfully.

Best regards

Petr

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Dear Nick,


I hope that you were able to convert data correctly and we can close the ticket.

Petr

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