Abstract
The creation of spatial information systems can be viewed from many directions. One such view is to see the creation in terms of data collection, data modelling, codifying spatial processes, information management, analysis and presentation. The amount of effort to create such systems is frequently under-estimated; this is true for each aspect of the above view. The accuracy of the assessment of effort will vary for each aspect. This paper concentrates on the effort required to create the code for spatial processes and analysis. Recent experience has indicated that this is an area where considerable under-estimation is occurring. Function point analysis presented in this paper provides a reliable metric for spatial systems developers to assess required effort based on spatial data models.