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Problem very slow loading/displaying of Shading. (.hgt files not loaded in RAM ?)

Markus shared this problem 17 months ago
Solved

Hello to the Team


Some Time ago, it was much faster in calculating / loading the Shading of height data.

There i remember you did tell that all the .hgt data get loaded to the RAM. (if ram is big enough)

Did u change this to each time from Flash memory ?


Reason is, that i use very big .hgt Files. (4 of them)

Can this be the Reason of slower loading and calculating ?

Best Answer
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Hello Markus,

oki, let's try it. In the next app version, memory caching will be also enabled for the SRTM1 files.

Menion

Replies (4)

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1

Hi Markus,

only the base HGT files, so file less than 3MB big, are loaded directly into memory. Bigger files are currently used directly from the disk so it really may be slower.

Bigger files are supported without any limits, but to be true, I've never tested their performance. You may give try and temporarily remove your more detailed HGT files and give a try to app internal files if there will be a significant difference. Most probably it will.

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Hello

Thanks for this information. Is it possible that in earlier versions of Locus, also big files have been loaded to RAM ?
If i remember right, i did check the Memory-Usage while using LocusMap Pro and it have been big, when i used my big files.

Now the Memory Usage is very small.
I have 7 GB of free RAM and they dont get used.

Maybe a change in Software that loads at least the surrounding 8 tiles + the tile with actual Position to RAM ? (9 Tiles at all)
Or an Expert add-on to load all to RAM ?

I would say: Load all .hgt data to RAM at startup. Because 3MB small tiles are loaded quite fast i think.
And the special users which use maximum 3 or 4 very big .hgt files can wait longer at App-Startup.

In my Case, i use this bigger .hgt Tiles for the Field of Work of my Mountain Rescue Unit.
And mainly to get the height-data at cursor. (for this i can leave the Shading off, thats good because then its fast)

But sometimes i want to use the directional Shading of Locus to more easily recognize mountains and valleys.

greets Markus

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1

Hello Markus,

oki, let's try it. In the next app version, memory caching will be also enabled for the SRTM1 files.

Menion

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1

Big Thanks for giving a Try...

Sounds Great.

I hope the loading to RAM is then not limmited to SRTM1 ? Because i use "SRTM 0.0625" or something close to this.
(~1,875 m ground- resolution at equartor)

It did work much faster some time Ago. Thats why i got to this Question.

greets Markus

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