The map shows the annual precipitation in Idaho. This is an Isarithmic map using Inverse Distance Weighted (IDW) interpolation to find the best estimation for isobars (contours) between weather stations where actual information exists. This was a decent method and had a minimal RMSE. The IDW interpreted somewhat detailed variations in temperature throughout the state.
Part II: Kriging Interpolation
This map also shows the annual precipitation in Idaho. This is an Isarithmic map using Kriging interpolation to find the best estimation for isobars (contours) between weather stations where actual information exists. The best statistics were obtained through the Spherical Kriging model which shows a progressive decrease of spatial autocorrelation (equivalently, an increase of semivariance) until some distance beyond which autocorrelation is zero.
Discussion:
The maps using IDW interpolation and Kriging interpolation look very similar. However at a closer inspection it can be seen that the contours that were interpolated for the IDW method represent a more detailed interpretation of the estimated values between the precipitation grid points on the map. It seems that the IDW picked up on higher level of variation in the points. This map used 15 neighbors and the optimal power to determine the best values for the contours. The Kriging Map, though similar is shows much less variation in the contours and did not pick up on small peaks in the precipitation variation. Despite this the max and min values for annual precipitation are very similar.
Map of the Week: Elevation map of Salem, OR
I chose this map because I wanted to show a relatively bad example of a raster elevation map. The map is of the city of Salem, Oregon and is meant to represent elevation values as well as city features. However, at first glance one might think this is a map of ocean depths. The qualitative value of the map is poorly done. Shades of blue were not a great choice to protray elevation, especially considering that Salem is not near the coast. I thought this was a good example of what not to do when creating an elevation map.
source: http://www.cityofsalem.net/Departments/InformationTechnology/GIS/Pages/ElevationMaps.aspx
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