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I am trying to make a set of raster layers of the Earth's magnetic field using point data collected over 21x31km at regular 300m intervals. I have tried 150 different combinations of kriging variables and ended up using Universal with a second order trend removal, default settings for the rest. This gave the most accurate predictions and the smoothest contours.

Problem occurs with the conversion of the intensity a raster (at 10m resolution) to aspect raster to get the magnetic direction. I get these artifacts between the locations of the original data points resulting in a whole series of X's. The magnetic field direction jumps 20 degrees over 5-6 pixels and then drops down 20 degrees for no apparent reason.

Why is it doing this? Any ideas on a better kriging method for this sort of data?

cb4
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Josh Guilbert
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1 Answers1

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The solution I came to after talking to the GIS ninja's across the road was to generate a coarser raster than I was after and then resample it. Method as follows:

1) Make the first raster with whatever kringing method you wish to use.

2) Output the cell size in some regular interval that does not cause the Artifacts, I would recommend getting 2-3 new data points between each observed. Make certain that the output cell size is divisible for your final resolution. e.g 300m -> 100m -> 50m -> 10m

3) In data management use the "raster to point" tool to get a new set of points for next Kriging.

4) If required use the clipping tool to remove any points outside of the orginal raster size.

Josh Guilbert
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