Teaching Raster GIS Operations with Spreadsheets

Abstract

Many universities are introducing courses to teach students the principles of geographic information systems (GIS). In addition to lectures, exercises with commercial GIS software are offered to show basic operations. Although students learn to execute such operations, the software may hide their internal structure and logic. We propose using a spreadsheet program as a teaching tool for raster operations such as filter and overlay. Spreadsheets offer a practical way to demonstrate and experiment with raster operations, because the raster structure is captured in the form of rows and columns. With this tool, students are able to perform and visualize operations as well as to see how the data are processed by the algorithms. Our approach is new in that we concentrate on the algorithms of operations. We make explicit which raster functions are actually evaluated when performing a particular operation. We conclude that there are good reasons for using spreadsheets in comparison to traditional GIS software when teaching raster operations. These are demonstration in class, simple user interface, familiarity to students, low cost, flexibility of changing cell values, ease of changing parameters, easy programming environment, and the possibility to look behind the scenes of operations by viewing the code.