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5 votes
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Changing values where two geometries are equal otherwise keep value with QGIS Virtual layer

b.DTV will be NULL when there are no duplicate geometries so a.DTV+NULL=NULL. With coalesce you can replace NULL with 0, whenever b.DTV is NULL: select a.DTV + coalesce(b.DTV, 0) as DTV, a....
Bera's user avatar
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4 votes
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Assigning Z value along line on raster using QGIS

Optionally create a small buffer around your line Rasterize your vector layer (Processing Toolbox/GDAL/Vector conversion/Rasterize with attribute or fixed value). It'll burn the the value into the ...
Zoltan's user avatar
  • 7,410
3 votes

Splitting lines and getting the lengths in QGIS

An other possibility is to use a virtual field in the attribute table, which can be created with the field calculator with the $lengthfunction. A virtual field will be updated automatically: https://...
eurojam's user avatar
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2 votes
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Merging attributes from line layer and polygon layer in QGIS

i think you can use the Join attributes toolbox from QGIS. first try with line and polygon shapefile (hex). If that fails, then you can try to create a very small buffer over the line shapefile and ...
noob_noob's user avatar
2 votes
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Summing equal geometries with identical columns in QGIS

Virtual layers are a good way to solve your problem. In this example a layer layer1 and a layer layer2 share attributes lanes of type integer and surface of type character. For calculating the sum of ...
Bernd Loigge's user avatar
  • 2,940
2 votes

Splitting lines and getting the lengths in QGIS

Update your length field with the $length function. https://docs.qgis.org/3.34/en/docs/user_manual/expressions/functions_list.html#length
Mr_Yum's user avatar
  • 1,114
1 vote

Changing values where two geometries are equal otherwise keep value with QGIS Virtual layer

The solution demonstrated by @Bera is correct for cases where there is a 1 to 1 equality of geometries from two layers. If the second layer has two or more features with geometries equal to features ...
Taras's user avatar
  • 33.3k
1 vote

Finding overlapping line geometries (including subsets) in QGIS

I'm a bit surprised how tricky this appears to be. Like you say, it's straightforward enough to find duplicates, but subsets of lines not so much. Anyway, here's a way of adding a visual indication of ...
SirLostalot's user avatar

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