Modeling Fundamental Geo-Raster Operations with Array Algebra

OLAP pre-aggregation techniques have proven to enable query time responses close to real-time in business and sta- tistical applications. In raster image databases (such as for geo services), similar data structures and operations appear. However, only one particular, comparatively sim- ple pre-aggregation technique is used there, namely image pyramids. We are working on systematically carrying over results from OLAP to geo raster databases. In this paper we identify a set of fundamental geo raster operations and formulate them algebraically, using a proven array model. We argue that pre-aggregation support for a few basic query patterns is sufficient for many practical situations.