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I am creating a map of islands and I created a land shapefile using water shapefiles and therefore the land shapefile doesn't have any of the original attributes of the water shapefiles. I'm wondering if I can still shade in islands somehow?

  • I think you'll have to give them a 'land' or 'island' attribute in a TYPE column Oct 5, 2020 at 18:06
  • how do I do that when the shapefile is one big polygon? with no unique IDs? I tried to look for tutorials but I found none.
    – Lisa Wang
    Oct 5, 2020 at 20:07
  • It sounds like you have 1 giant 'single part' feature. If you run a the single part to multipart tool you can break up each polygon into its own feature... does that sound like the issue? Oct 5, 2020 at 20:10

2 Answers 2


You have several options to shade both the islands and the water (sea, ocean etc).

Shading part of a shapefile:

using symbologies:

1.- the style options of QGIS are very varied, you can assign to your polygons a simple symbology or category, then in symbol layer type you assign gradient, and varying the options, for example, gradient type: radial, reference point: centroid and several reference point1 values enter image description here

If the layer has contiguous polygons as in the image it looks better if you assign in coord mode: viewport enter image description here

2.- Another option is, assign in symbol layer type: shapeburst fill, then you can assign two colors for the degradation.

Or, most cooler, you can work with color ramp, editing the colors. You can assign multiple levels, Modify the set distance and blur strength parameters enter image description here

3.- If this is not enough, you can assign additional effects in the style options, select draw effects, then click on the yellow star. In the dialog box try the different effects

enter image description here


You just only want to shade them in for symbology? Your image looks like this is done already for Northern Quebec. There is a symbology type called Inverted Polygons if that's all you need. Inverted polygons get a little funny with some CS though.

Why are you restricted to only using the water?

If you don't need the attributed of the islands or if you have a way to join them later, you might have to do something a bit more tedious like:

  1. Draw a feature representing your study are (+ some extra) and call it 'land'
  2. Use your water layer to clip 'land' with it
  3. Single-to-multipart tool on the 'land'
  • There are islands that have points over them showing when they have been visited. I want to shade only those specific islands in.
    – Lisa Wang
    Oct 6, 2020 at 0:55

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