Spatially explicit land-cover change modeling and change projection are critical tools for environmental planning and biodiversity conservation. In these models, proximity to roads is universally identified as a critical explanatory variable in land cover change. Land-change projections therefore are severely limited unless the road infrastructure is similarly modeled and projected. Few attempts have been made to model road development and all require the specification of critical parameters that are not empirically derived but set by trial and error. This doctoral dissertation research project will develop an empirically parameterized road-extension model to project the development of a road network that preserves the existing spatial arrangement. To pursue this objective, the doctoral candidate will answer the following questions: (1) How can the spatial arrangement of a road network be quantitatively characterized? (2)What is the relationship between the network''s spatial arrangement and regional characteristics? (3)How can this relationship be incorporated into road extension simulation to replicate the network pattern? (4)Does the model improve road extension simulation and land change projection, and if so, by how much? The student will measure topological and geometric attributes of a road network to classify patterns. Empirical relationships between the road network patterns and regional characteristics will be used to control the projection of road development through confining location of endpoints and routes of new roads. The road model is expected to project the road extension by giving the location of individual roads while maintaining the pattern of the entire road network. The new model to be developed in this project will be validated using data on the growth of the road network in lowland Bolivia from 1986 to 2000.
This project will simulate the road extension under the current or planned development strategies. The model to be developed through this project will enhance predictions regarding the location and the intensity of future human land use and help to prioritize land for biodiversity conservation planning. The project also will lay a foundation for theoretically and practically addressing the interplay between land use and road infrastructure development. By embracing land-cover characteristics in modeling road extension, the project will acknowledge roads as an endogenous factor of land change. A land-change model that dynamically integrates the road-extension model will incorporate the feedback between the road and land systems. The results of the research will be incorporated into a future release of the Land Change Modeler for Ecological Sustainability as part of the IDRISI GIS and Image Processing System. Because IDRISI is a non-profit system intended to serve related research, education, and government fields at low cost, the road-extension model thus will be made available to thousands of users in these communities. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
