Map Algebra Created by way of the 1980′s by Professor C. Dana Tomlin as part of his PhD matter work, Map Algebra offers a vocabulary and conceptual framework for classifying methods to combine map data to generate new maps. Although primarily applied to raster data sets (GRID and image data), the same concepts can be applied to many types of cartographic information, and it has since been extended by Dr. Tomlin and others to 3D, time and other domains. People use Map Algebra for a broad array of applications including: suitability modeling, surface analysis, density analysis, statistics, hydrology, landscape ecology, real estate, and geographic prioritization. Azavea has used Map Algebra on several projects and it is at the heart of our Decision Tree product.