GIS Application Development

Applications are the highest level of customizable software. Though there is a great deal of commonalty in the basic spatial query and display functions, there is still a need for other complex purposes. We need additional applications because needs vary between organizations. Commercial GIS development is driven by market demands. The software vendors only act in response to what is financially viable for their market share.

Application improvement does not mean reworking the GIS software, but instead implies customizing applications to meet specific needs. The applications may be as simple as a set of preferences that are stored for each user group or individual and are run as a macro at startup time. Or they may be a very complex query that selects a group of layers, identifies features of interest based on attribute ranges, creates variable width buffers, performs a series of overlays and produces a hard copy map. In either case, an application is required to convert the user's ideas into a usable, stable product.

Applications are not restricted to user-defined needs. The most important of these are the data administration functions for maintaining the quality and integrity of the database, such as quality control, verification, editing, back-up routines, and security.

Each step needs to be fully defined, according to the specifics of the GIS program. The main point is to identify all the basic steps and to emphasize the importance of planning and executing each one.