Digitising, editing and structuring map data
This chapter reviews several techniques that are found within commercial Geographical Information Systems (GIS) or are used in association with GIS to help in solving problems concerned with finding sites that meet user-specified criteria, finding routes through networks and with allocating resources. It examines the use of network models for solving problems concerned with determining optimal routes between two or more places. A problem that arises with weighting of the factors to be considered in a weighted overlay operation, is the selection of appropriate weights. Linear Programming (LP) is a well-established method of finding an optimal solution to problems that require several factors to be balanced against each other, subject to certain constraints. The chapter introduces spatial interaction modelling as a means to describe and predict flows between locations. Identification of land sites that meet particular criteria is one of the main spatial analytical applications of GIS. Location-allocation models are a relatively complicated form of spatial interaction model.