Researchers often collect samples from strategically dispersed sampling locations but would like to present the results as continuous surfaces. For example, the estimation of the temperature in ungauged areas using the temperature values from nearby weather stations. The SURFACE INTERPOLATION TOOL allows users to upload their own geocoded data and create continuous layers from discrete data points. In this application, user can upload data in the form of CSV files and create a surface to view on the map. There are three different interpolation methods available: INVERSE DISTANCE WEIGHTED, NEAREST NEIGHBOR and SPLINE. Additional description is also available within each application.
The INVERSE DISTANCE WEIGHTED interpolation method assigns weights to known sample values based on the distance: higher weights to the nearby points and lower weights to the distant points. This method performs well when the sampling points are dense enough to capture the local variations.
The NEAREST NEIGHBOR interpolation method finds the nearest sample values and assigns them weights based on proportionate areas. This method generally works well with clustered scatter points.
The SPLINE interpolation method uses a mathematical function that minimizes overall surface curvature. This method is good for smoothly varying surfaces of phenomena such as temperature.
More information on interpolation methods can be found at: