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I work for a local authority so use data covering a large area. Therefore some datasets I use become large and cumbersome.

For example I have a vector layer for contours and a raster layer for hillshade. As I am relatively inexperienced I created Booth of these of a series of tiled points and created a single file. I am happy with the results but performance is slower.

What are the main options available to improve the performance of the vector layers for a single user on one PC and for a team? This should allow me to both display and analyse the data efficiently.

What are the main options available to improve the performance of the raster layer?

  • Do you have access to a server, so you could host your own WMS? Could you reduce the resolution of the DEM/countour layer? What do you mean by "I created both of these of a series of tiled points and created a single file"? Aren't they two files? Why do you actually need hillshade? Would it be feasible to turn on these layers only when you really need them? – Erik Sep 12 at 9:32
  • To improve performance of a raster layer in qgis, convert it to a single GeoTiff and add external overviews (fastest) or a virtual raster with external overviews (generally fast). You can create a virtual raster then save it as a GeoTiff. Overviews are created in the properties view (right click the layer). – vinh Sep 12 at 15:52
  • You could try creating a geopackage. This uses a sqlite database and can include optimisations for both vector (spatial index) and raster (overviews and internal tiles). – vinh Sep 12 at 15:54
  • In addition to the suggestions to build a spatial index for vectors and pyramids for rasters , you might check out Settings - Options - Rendering for some settings that affect rendering speed. You can generalize/simplify vectors like contours (those from LiDAR are often quite noisy) as well. If you have rasters with complex symbology, especially 32 bit floating point, converting them to rendered 8 bit can greatly improve speed. If you have complex labeling expressions, masking or locations, or complex symbology expressions or symbols, those can slow drawing. – johns Sep 12 at 17:12
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For your contours, you can

For your raster, you can

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The best way to manage your large datasets is to store them in a spatial database like PostGIS. The loading speed will be twice faster.

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    PostGIS will also allow you to do very fast spatial operations. – ragnvald Sep 12 at 5:09
  • Thanks Simon, I don't know much about databases, so will check it out. – boberdorf Sep 12 at 10:11
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    @boberdorf This answer is a bit of an over generalisation. Where I work, our very large datasets are stored in a remote spatial database (which is tuned for speed) and it's still way quicker to pull the data down to a local filesystem format to do anything with it. A local database may be quicker, but will have overhead in setting up and tuning. – user2856 Sep 13 at 0:44
  • Geoserver is not a spatial database. – user2856 Sep 14 at 2:49

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