In Spatial Interpolation Comparison (SIC) exercises, participants are invited to estimate values of a variable at given locations by using information provided by a subset of the total number of measurements of the variable (see Figure 1). The algorithms of the participants are then contrasted with each other by comparing the estimation errors of each spatial interpolation technique. Participants are further invited to present their techniques in a manuscript that is reviewed by an editorial board prior to the publication of the exercise.