ABSTRACT
Geographic Information Systems (GIS) were ‘born’ on land; they are around 35 to 40 years old, but only about 15 years ago did they ‘migrate’ to the sea. In this process ‘…as fish adapted to the terrestrial environment by evolving to amphibians, so GIS must adapt to the marine environment by evolving and adaptation’ (Goodchild 2000). The domain of GIS concerns georeferenced data, plus integration and analysis procedures, that function to transform the raw data into meaningful information that can support management decisions. In any environmental GIS, after defining the nature of the problem, the initial activity will be to measure aspects of the variable or natural process including both spatial and temporal perspectives. Variables or processes will have three types of properties that need recording: (1) features; (2) attributes; and (3) relationships. GIS will have the ability to store and access digital details of these measurements from a computer database. Then, measurements will be linked to features on a digital map. Aspects of the features will be able to be digitally mapped as points, lines, and polygons (vector) as well as pixels and voxels (raster). The analysis of collected measurements as well as the application of numerical manipulations or modelling algorithms may produce additional data. The combined analysis of several datasets in a GIS environment provides meaningful information for natural processes and it is the core of the GIS technique. The depiction of the analysed data in some type of display (maps, graphs, lists, reports or summary statistics) provides for the communication media of GIS results or output.
