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spatialthoughts / qgis-tutorials

Source files for sphinx-based website
http://www.qgistutorials.com
Apache License 2.0
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Making Interactive Reveal Maps (QGIS3) — QGIS Tutorials and Tips #191

Closed utterances-bot closed 2 months ago

utterances-bot commented 2 months ago

Making Interactive Reveal Maps (QGIS3) — QGIS Tutorials and Tips

https://www.qgistutorials.com/en/docs/3/interactive_reveal_maps.html

kannes commented 2 months ago

I just tested my theory successfully \o/

You can use an Inverted Polygon layer instead of the layer with the one point in it. So -> Temporary Scratch Layer -> Inverted Polygons -> Geometry Generator -> @canvas_cursor_point

It might be slightly less work for QGIS if one uses a point marker with a bigger size instead of the buffer but I have no idea if that makes a big difference. Seems fast enough for me already.

Performance really depends on the masked raster layers though, a live hillshade layer takes a while to compute so if the reload interval is too high, QGIS cannot render the hillshade in time and the "lens" might just not appear.

image

spatialthoughts commented 2 months ago

@kannes Thanks for the suggestion. This workflow is much simpler and elegant. This has now been updated in 22ad4d85f329cfbf6a8588ea306a49529ff4fb87 and updated on the website.

alunarpoetry commented 2 months ago

Good night. I hope they are well. I have a problem at the end of the exercise: I did everything in the tutorial, but when I move the cursor around the map, nothing is revealed. Only if I click, the buffer moves, but abruptly, it doesn't move like in the tutorial. What am I doing wrong? I hope you can help me, thank you very much!

spatialthoughts commented 2 months ago

@alunarpoetry Check Step 17 again.

alunarpoetry commented 2 months ago

I did it, but it doesn't work :(

spatialthoughts commented 2 months ago

@alunarpoetry You can download this ZIP file which contains the solution to this tutorial. Unzip and load the interactive_reveal_maps.qgz file in QGIS and it will work. https://github.com/spatialthoughts/qgis-tutorials/releases/download/solutions/interactive_reveal_maps.zip

Once it works, you can see how it that project is set and find your mistake.

alunarpoetry commented 2 months ago

Thanks so much!! In the properties of the Rendering I had Reload Layer Only, and i put Reload Data, and the it moved. Thank you so much!!