Objectives
Using Geographic Information Systems (GIS) tools we created a buildout model for the New Jersey Highlands, analyzed developable land to determine in which zoning categories they fall, and completed a population estimation using developable lands and their corresponding zoning. Based on current zoning regulations for the Highlands region we wanted to predict the speed at which the population is growing and how this population growth may affect the landscape. This data could then be used to predict land use problems with regards to the environment, and or human uses of the Highlands region. Buildout models help visualize the land use changes that continue to alter the New Jersey Highlands. These models show where development is likely, where development will be concentrated, and where it is occurring most rapidly.
Methods
Specification of study area and development restrictions: We received, from the Environmental Defense Fund (EDF), a Highlands zoning shapefile of all municipalities with land in the highlands. This was our study area. The land use/land cover (LuLc) Department of Environmental Protection (DEP) maps for New Jersey were then clipped by the zoning to obtain LuLc within the EDF specified Highlands boundary. This LuLc file was then used to create urban and wetland shapefiles for the Highlands area. The wetlands layer included all water other than streams. The stream layer was assembled using countywide DEP data and clipping by the Highlands boundary. The final development restriction was slope, which was derived from a USGS 30m digital elevation model of the area. The slope information was reclassified and land with slopes of 15% or greater were isolated and converted to an exclusive file. The four development restriction files, i.e. urban, wetlands, streams, and slope, were converted to raster grid files. Streams were not buffered because of the nature of the vector to raster conversion coupled with the pixel size used. This conversion technique used along with the cell size used to create the raster layer, made for a raster stream file much larger than the vector stream file. The raster cell size created approximately a 27 meter buffer on either side of the stream. The conversion of the other development restriction layers were comparatively much more accurate, and wetlands were not buffered because the study intended to determine the maximum build-out potential, and according to this criteria, wetlands could not be buffered. These procedures determined the land that would be considered undevelopable within the highlands.
Determining the extent of developable land: After converting all necessary GIS data layer to raster grid files, the appropriate erases could be performed in ArcView with respect to the Highlands zoning file. This step left a coverage showing land that could possibly be developed while maintaining the original zoning classifications.
Determining Potential Dwelling Units and Population for each zoning class: Using ArcView, the remaining developable land in terms of acres was calculated according to the number of pixels associated with each particular zoning class. This acreage information, combined with the zoning information, was used to calculate the potential number of dwelling units possible for each zoning class. This figure was then used in conjunction with the 1990 Census data specifying average number of people per dwelling unit in New Jersey, to reveal the potential population per zoning class.
Graphics
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