[closed] Elevation data and .HGT elevation files support

[alexlong]

Hi and thanks for elevation data and .HGT elevation files support
Some questions:
1. How can I use elevation data feature? When I use any map the only thing I see on the screen is a gray disappearing square with a word DEM and nothing more.
2. Is there a chance to turn off elevation data on the screen in case I do not need it?
3. How can I open .HGT file in AlpineQuest?

Thanks again for the update

[alexlong]

That's OK with #1
# 2 probably OK
# 3 is a question. Where I should place .HGT file to see elevations on the map? I think I can do it offline

[alexlong]

I think it would be better to have a chance to turn on/off manually elevation data download and display
I use online map with automatic elevation data download and sometimes I have problems with downloading main map (let's say Google) because elevation data downloading is slower than Google.
My region is situated higher than 60°N so I do not need elevation data downloading for now but AQ tries to download it anyway so my Google online map became working a little bit slower.
My internet channel is fast but if I have bad internet somewhere I think it would be a big problem.

[alexlong]

I think it would be better to have a chance to turn on/off manually elevation data download and display

Sorry, my fault. I have found it

[Yemble]

I'm having a look at this as well. So for it looks great and it is perfectly calibrated to the OSGB maps (once you have configured the elevation display to be in metres rather than feet).

Downloading is the usual PITA as it only seems to work from a particular minimum zoom level (equivalent to 1:250K Road Atlas). So if you want to cover the entire UK map, then you will need to spend some time panning around the map in on-line mode. However, this appears to be a one off task as the elevations remain present in off-line mode.

The coverage indicator appears to be via an optional "DEM Storage Visualisation" layer which defaults to 50% opacity, rather than the usual red and green squares. This layer is not required to display the elevations, so it can be turned off once the elevations have been fully downloaded.

The DEM cache appears to be stored in the .../cache/dem folder in AQE file format.

[Yemble]

DEM cache for entire UK (with the exception of North Orkney - above 60deg N) occupies 492Mb in six AQE files

[Yemble]

I can also confirm that the DEM cache can be transferred between devices, so there is no need to re-download it. In fact, as soon as you transfer the cache files, AQ picks them up automatically and applies them without the user having to do anything.

Perfect

[Psyberia-Support]

Hi and sorry for the late update.

Yes you can activate/deactivate the use of the DEM data when you want, and also check the coverage by displaying the "visualisation layer".
Visualisation happens when zoom ID is higher or equal to 6, download of data when zoom ID is higher or equals to 10.
I'll soon make an online help.

It's also planned to download elevation data using the store area tool, so you won't have to manually store large area by moving around like you did Yemble...

Data is downloaded in the "/cache/dem/" folder. There is one data file per 10°x10° area. You can manually delete files for areas you don't want anymore (right now the "Delete data" from the app will download all the files together).

[alexlong]

How can I use separate .HGT elevation files in AlpineQuest? I have some. What do I do to see them in AQ?

[Psyberia-Support]

Hi Alex and sorry for the delay.
You can put your own .HGT files in the "/cache/dem/" folder and the application will use them.
Let me know if you have any issue with this
Best regards

[alexlong]

Hi.
1. I did not quite understand how to use my own .HGT files. I put them in cache/dem but nothing happens and I do not see any offline elevation data.
Should I keep the "Download and use elevation data" turned on in "Elevation data" section of "On-demand maps" to see my own off-line .HGT files or should I turn it off?
Could you please explain it here, or in PM, or somewhere in online help on the AlpineQuest homepage?

2. I download .HGT files by using a small application from PlayMarket called DEM1 - World Elevation Data
Actually I can get them through torrents or here —> SRTM Eurasia. The way a get SRTM files is not too important.
For example I downloaded one SRTM file of the Crimea through DEM1 - World Elevation Data. The file is N44E034.hgt

DEM1-dem.jpg

(33.35 KiB) Downloaded 4789 times

Now I launch AlpineQuest and turn "Display grid" on to be sure I am on the wight place, that is N44E034

AQ-dem.jpg

(58.44 KiB) Downloaded 4789 times

When I turn on the "Download and use elevation data" in "Elevation data" section of "On-demand maps" and check "cache/dem" I see N40E030.AQE in the "dem" subfolder. I am in N44E034 but I see N40E030 in the cache.
Is it right?

[alexlong]

Just in case I share my hgt file from DEM1
https://yadi.sk/d/jQ0-kb5D354ML3

[Psyberia-Support]

The current version doesn't handle well when you use your own .HGT file together with the application auto-downloaded files.
So try the following thing:
- in the app, check the "use local storage only" to prevent the application to download new data;
- you also need to have "Download and use elevation data" checked (now also available in the "Maps" menu under "Options");
- close the app and using your file explorer, delete all the .AQE files and only live your .HGT files;
- start the app.

By the way, I've just published a new beta that correct the ugly grid labels.

Some technical info:
- the application uses .AQE files covering an area of 10°x10° instead of 1°x1° for .HGT files, that's why you see "N40E030.AQE", this files is used to store data from [N40-N50[ and [E030-E40[. But these files are downloaded by small parts.

[alexlong]

Hi and thanks for update.
1.

you also need to have "Download and use elevation data" checked (now also available in the "Maps" menu under "Options")

You just duplicated it in Options to make it convenient to work, right? It's the same as in On-demand maps and when I uncheck it in Options it is automatically unchecked in Available maps, right?
2. If I put N44E034.hgt in dem folder and keep working online and do not check the "use local storage only" the application does not make any AQE file untill I move to some other place out of N44E034.hgt coverage? If I am out of N44E034.hgt coverage a fille AQE appears?
3. When I applied N44E034.hgt I see the cache size 24.74 mb that means the application considers .HGT file as a part of cache so if I choose "clear data" the application clears cached data and deletes .hgt file. I did not know it and I was rather surprised when I saw it disappeared. Is it normal?

[Psyberia-Support]

1. Yes you're right!

2. Also a yes. As long as you stay inside the area covered by an .HGT file, nothing will be downloaded. But be careful that:
- As soon as you go outside of N44E034.hgt, say N44E035.hgt, the .AQE file N40E030.AQE will be created and will be "responsible" of the area from N40 to N50 and E30 to E40 so your file N44E034.hgt won't be used anymore. That's why I said that it's not very easy to use both your own file and the one downloaded by the app. I'll try to add an user setting to completely disable the download of .AQE file for those who only want to use .HGT files...
- Some other things may lead to the download of .AQE files, not only moving the map center. For example when you display the details of a waypoint or a track, the application may download some elevation data around this point, or to get the elevation profile of the track.

3. Also a yes, all the "dem/" folder is considered to be the "cache", and will be deleted entirely when removing the cache. I can try to change this if you believe it's not correct...