Removing Trends: Clarification

Discussion created by kirstenfalzarano96 on Aug 7, 2012
Latest reply on Aug 8, 2012 by kirstenfalzarano96
Hi There,
  I thought I understood what a trend was, but now I am a bit confused. In my dataset, I am using kriging to interpolate a soil surface based on elevation measurements. The surface covers an area of 9x8m, with a slope of 30cm across approximately 9m (nw to sw direction). When I look at the data in trend analysis, there is a first order trend, which corresponds to the slope. Is the sloping trend something that I want to remove, or is this the source of the autocorrelation in my data? According to one of the geostatistical analyst tutorials, if your data is represented by a sloping hill (plane) you can keep the trend in the data, unless it is too simple to represent the true surface. Is the easiest solution to try both and pick the best cross-validation results? Finally, I am creating interpolated surfaces for several different soil layers and comparing them. Is it best to use the same method/parameters for all? What if one method (ie ordinary kriging with trend removed) works better for one layer and not another? Should the method that works the best overall be selected?

Thank you for any advice - this forum has been VERY helpful to me!