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I am a novice QGis user, and I’m sure there is an easy way to do what I want, but I don’t have a clue as how to start. I downloaded a bunch of SRTM DEM sections and combined them into one raster layer. An image of my elevations and rivers is shown here.

The problem is that the area covered is all of eastern Europe, so it takes a long time to refresh whenever I pan around the map. Is there a way to speed this up?

I suppose that things would go faster had I not combined all the sections into one raster, but I want all the sections to have the same properties, and don’t want to have to change the properties for each segment one-at-a-time every time I change properties.

If someone could point me in the right direction on this that would be great!

DarkCygnus
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Mark Polczynski
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1 Answers1

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There are several things you can do to increase your rendering performance, most of them under Settings -> Options -> Rendering:

QGis Settings Options

You could use render caching to allow QGis to spare some computations when redrawing your rasters. You can also check render layers in parallel by using CPU cores to give the rendering more resources, as well as enable feature simplification for new layers. You can also uncheck the less jagged lines option to prevent the use of that extra performance it takes.

Another trick I usually do when moving around large maps and rasters is to uncheck the render option, move and pan around, and then check the render option back again on the desired region. This I found prevents unnecessary rendering when moving, panning and zooming repeated times. This is the render feature I was mentioning, you can find it in your bottom bar:

enter image description here

You can also check this related GIS Stackexchange question if you want to know more options.

Hope this helps.

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DarkCygnus
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