The road extension model in the land change modeler for ecological sustainability of IDRISI

Road development is an important proximate cause of deforestation and consequent biodiversity loss. The interaction between road extension and land use calls for an integration of road simulation into land change models to improve model performance. To date there have been few attempts to simulate road development to support land change modeling. The objective of this research is to develop a road extension model to simulate roads network expansion. This road extension model forecasts the location of individual roads at local scale and produces the given spatial pattern of road network at regional scale. Locating individual roads is divided into two consecutive steps, identifying endpoints and locating routes. Spatial pattern is controlled through altering the local road growth process, specifically limiting the number and locations of endpoints. The road extension model was released in 2006 as a component of the Land Change Modeler for Ecological Sustainability in IDRISI 15.0 (the Andes Edition). The model was applied to simulate scenarios of different road placement strategies in lowland Bolivia. The model results showed that the simulated road network exhibited varying spatial arrangements under different pattern parameter settings. The result provides insights into the ecological consequence of human land use policies. It also calls for an empirical based pattern parameter specification to predict road expansion that maintains existing network patterns.