Interpolation

 In this week's module, we used different types of interpolation to create rasters from the same dataset and examined the differences.  Several DEMs representing the water quality of Tampa Bay were generated from point features and compared to one another.  Because of the haphazard arrangement of the sampling locations, Thiessen polygon interpolation was not ideal for this particular analysis.  Similarly, spline interpolation inaccurately accounted for an area as having a high concentration of BOD (biochemical oxygen demand) and the original dataset needed to be modified to rectify the raster.  IDW interpolation (shown below) provided the most realistic raster considering the spatial distribution of the sampling locations and their associated BOD concentration values.