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I am using TIN Interpolation to interpolate point features based on their cost attribute (value is between 0 and 5000). Graduated symbology creates something like this:

enter image description here

However when I am using TIN interpolation, I get these weird white stripes (image below). I've been trying for hours to get rid of them. They really look out of place..

enter image description here

Anyone have an idea how to get rid of these?

  • Which tool or algorithm did you use? – AndreJ Mar 3 '15 at 13:04
  • I used Raster > Interpolation > Triangular Interpolation in QGIS. I think its GDAL tools – SpatialBuilder Mar 3 '15 at 13:42
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I have had similar problems when interpolating data of a scanned image which I imported in a WGS84 projection using its pixel-coordinates (for practical reasons). The points I used for the interpolation were about 0.010 units apart. I retried after multiplying all coordinates by a factor 10^6, and the problem was gone. If this also works for you, it is likely due to precision/rounding applied in the interpolation code, so hen please make an issue for it on hub.qgis.org!

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