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Optimizing an interpolation method. Geostatistical Wizard

Question asked by charly_ on Sep 21, 2014

Hi, I need to interpolate in ArcGIS 10.1 soil data (organic matter content, nutrient content, pH, etc.) from a set of soil sampling points to a surface which this set of points lays on.

 

I am  considering Kriging or Inverse Distance Weighted.

 

I guess that using the Geostatistical wizard (in the Geostatistical Analyst toolbar) is the best option since the wizard has “Optimize the entire model” and “Optimize power value” buttons for respectively both interpolation methods.

 

But I have seen that for certain attributes or values to interpolate, it can be obtained a lower RMS by Kriging than by IDW, and on the contrary for other attributes.

 

My questions are:

 

  1. How to know in advance which method gives better interpolation result (lower RMS –or any other quality indicator-)? Is it necessary to achieve it by trying to change as many different parameters of both methods as possible?
  2. Is there any other quality parameter different from RMS?
  3. Can Kriging be an exact method when optimized with the Geostatistical wizard? (as far as I know, Kriging isn’t an exact method).
  4. Is there any criteria to know the most proper parameters of an interpolation method (such as, for IDW: Neighbors (min and max), sector type, semiaxis length, angle,  search neighborhood)?
  5. Any documentation with answers?

 

Thanks for any help given.

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