Few tools are as powerful in city planning as GIS. GIS, which stands for geographic information system, is a computer software system, which planners can employ for geographic analysis. The practical applications of GIS software are vast and the full capabilities of the system can be deployed to perform many mapping tasks. Listed below are a few applications that can help enhance community planning activities along the coast.
Through the use of GIS, local government officials can manipulate and utilize a vast array of curated geographic datasets that provide insight into the environmental attributes of a region. One such dataset is the National Land Cover Database. Land cover data is compiled by the U.S. Geological Survey and provides basic information on the surface characteristics of land within the United States. By utilizing land cover data, planners can determine the amount of impervious surface covering the region, locate large wetlands and identify farmlands. Analyzing land cover data is also a good way of identifying natural areas that might have high conservation value or are vulnerable to urban development.
Another major source of data for GIS analysis is the U.S. Census. Census data, when used in conjunction with GIS map layers, can provide a comprehensive picture of changing demographic trends within a region. By overlaying natural layers, such as creeks and watersheds, planners can determine which areas of a city or town may be subject to environmental problems due to encroaching development.
The ease with which geographic layers may be added or subtracted from a digital basemap is arguably the defining feature of spatial analysis within GIS. By storing map elements as computer graphic formats, vast quantities of geographic data can be deployed with relative ease. Slope, hydrography and soil types are all examples of natural attributes that can be easily stored and manipulated within GIS.
The applications of GIS though are not simply limited to city or region-wide analysis. GIS can easily be used for more discrete spatial analysis involving a few acres or even just a single parcel. One GIS analysis technique frequently employed for small sites is a suitability analysis. A suitability analysis is essentially a tool that can be used to rank or prioritize different portions of a site according to how it meets the needs of the site’s end users. Typically, a suitability analysis is used to evaluate a site’s potential for future development, but it may also be used for other purposes as well.
In coastal North Carolina, The Nature Conservancy employed a suitability analysis to provide guidance on where to site living shorelines. The suitability model developed by The Nature Conservancy looked at three primary factors: wind wave energy, boat wake energy and proximity to marsh. (View the Living Shoreline Explorer.)
The sites were then scored using the factors inputted into the suitability model. Using a 30-point scale for the model, individual living shoreline sites were ranked accordingly: a score of 25-30 indicated suitability for a fully natural living shoreline, a score of 10-20 indicated suitability for a hybrid living shoreline and a score of 0-5 indicated an unsuitable site. Though a suitability analysis is no substitute for public deliberation and debate, it can be a powerful tool in helping prioritize land use decision making.
The ability to discern patterns in urban development through map analysis is one of the defining features of the planning profession. By utilizing GIS, this process of map analysis has been greatly streamlined and taken to new heights. For coastal planners in Alabama and Mississippi, there are a whole range of GIS capabilities that can be tapped to foster a greater understanding of the coastal ecosystem and its impact on urban development.
Additional information on GIS can be found in the December issue of Water Log (page 13), a legal reporter published by the Mississippi-Alabama Sea Grant Legal Program, where I discuss GIS and how it may be applied to analyzing local fisheries.
Meet the author
Stephen Deal
Extension Specialist (Land Use Planning)
Stephen works with floodplain managers, building officials, city officials, scientists and Sea Grant partners to provide information and training related to flood and storm resilience. He holds a... Read more
Phone: 228-435-9527
Email: [email protected]