Two statistical problems occurring in the effort to analyze thematic maps and mapping are determining the accuracy of thematic content and comparing factors studied in thematic mapping. Statistical procedures applicable to thematic mapping involve sampling, determining accuracy, and comparing factors. A sampling procedure using an unaligned pattern within a square grid network is applicable for use with thematic maps. Sample size may be determined using the binomial distribution based upon the confidence interval to define the true mean of the population within certain limits. The confidence interval may also be used to define the upper and lower limits of the accuracy of the thematic map. - from Authors