Duplicate points removed in Spatial Analyst are not always the best choice

Description

When running datasets that have duplicate points through a suface interpolator operation (IDW, Spline, Kriging) in Spatial Analyst, the points that are removed are not always the best choices.

Cause

When a point coverage contains more than one point with the same XY coordinate, the Spatial Analyst surface interpolators will process them out. The first point encountered at a particular location is retained, and all other subsequent ones are removed from consideration.

This poises a question on the validity of the final result, as the criteria for deciding which value to use for surface interpolation is the order encountered.

Solution or Workaround

• Remove the duplicate points before running the surface interpolators. See the Related Information section for articles on how to do this.
  
  
• Use the Geostatistical Analyst, as it provides more control over the decision process for which points are used.