Developing small area network planning models using desktop GIS

Personal computer implementations of urban transportation planning (UTP) packages have resulted in a proliferation of modeling efforts. However, staff experience and availability, particularly at small planning agencies, has not kept up with this proliferation, and many agencies that could benefit from a model go without. As many UTP models are complex and difficult to use, improved graphical interfaces and visualization tools are needed to create more intuitive modeling environments that take advantage of limited or dwindling staff resources. Furthermore, new opportunites exist as more and more graphic-based data are becoming available via the internet and CD-ROM from sources such as the Census Department, the Bureau of Transportation Statistics, and aerial/ortho-photography projects. In this paper, tools are presented and steps are recommended for developing UTP models using desktop geographic information systems. Using the city of Ames, Iowa, as a case study, these procedures and tools are shown to facilitate integration of spatially referenced data for efficient model development. Several GIS-based techniques are also presented for enhanced visualization of model adjustments in calibration and validation.