Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I have a points layer and I want to create an interpolation grid with QGIS 2.0. If I use Raster -> Analysis -> Interpolation the extent of the output raster is good (rectangular shape) but it doesn't reflect the original values of the points layer in input. The values of the raster are the result of interpolation calculations.
enter image description here

If I use Raster -> Interpolation the output file reflects the original values of the input points layer, but its shape is not what I'm looking for. enter image description here

I don't see options to get the "original values" with the first method or to choose the extent of the area with the second one. So, how can I choose the shape-extent of the interpolated raster and, at the same time, be sure that it will reflects the values of the input layer?

share|improve this question

1 Answer 1

There are many algorithms of interpolation, each one with its characteristics. If you want to limit the results to the original values, you need to choose:

  • the TIN algorithm (with GRASS GIS: v.delaunay + tin.to.raster.py of Antonio Alliegro)

enter image description here enter image description here

With GRASS GIS v.surf.rst and a MASK covering the original points

enter image description here

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.