I have xyz points. I have imported these XYZ points into QGIS and need to create a raster from these points. I have used the raster interpolation plugin and I used IDW as the interpolation method. I got this raster (The following snapshot). Why it is like this? How I can fix it?

enter image description here

The average distance between points are 15m. In the above snapshot, the distance coefficient p is 2.

In the below snapshot, the distance coefficient p is 15. I have to mentioned that I used the IDW method.

enter image description here

What distance coefficient p. I need to use.

Any Idea?

  • 1
    What's wrong with it?
    – user30184
    Jan 29, 2018 at 13:28
  • These black and white points are the points which i have created the raster based on . why this is like that?
    – Mike
    Jan 29, 2018 at 16:53
  • The radius that you have used for IDW is obviously rather small. Technically the raster is OK but you may want to adjust your parameters.
    – user30184
    Jan 29, 2018 at 16:57
  • Can you please tell us something about your data (source)?
    – Stefan
    Jan 30, 2018 at 11:49

2 Answers 2


The IDW method calculates weighted average of the given points. The weight is inverse proportional to the distance between grid point and known point. P is used in the weight as a power of the distance. So the more you increase P, the less affect has a point to its environment. The usual value for P is 2. I would reduce the resolution of the output raster to the average distance of points and I would reduce P to 0.5-1.5 to have fewer local peeks.

An example P=2


And P=0.5


You may give a try to triangle interpolation.


try to use "rasterize (from vector to raster) instead of interpolation (if you open it as text layer firstly you need to save it as layer file)

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