Characterization of the Ashepoo-Combahee-Edisto (ACE) Basin, South Carolina

The ACE Basin Characterization includes a geographic information system (GIS) component. GIS is a computerized system for the collection, organization, analysis, and display of data with a spatial (geographic) reference. A GIS organizes spatial information for display as maps, tables, or graphs and empowers people to analyze the information for spatial relationships among multiple layers of data. The information in this product is provided to allow environmental professionals, land use planners, and the public to visualize and assess spatial relationships among important attributes of the ACE Basin.

A decision was made at the start of the ACE Basin Characterization project to base evaluations of the status and management options for the ACE Basin ecosystem on a comprehensive watershed approach. Much of the data collected in the ACE Basin extends beyond the boundaries agreed upon using the watershed approach. Because of this, all of the spatial data layers were clipped to the watershed boundaries, thus eliminating any data not contained within the project boundary. Data layers included on the CD-ROM were chosen based on their integral relationships to the ACE Basin ecosystem. Spatial data sets are provided as ArcView shapefiles and accompanying data tables. The shapefiles include point, line, and polygon vector coverages representing a variety of spatial data themes. Examples include sediment sampling locations (point), elevation contours (line), and National Wetlands Inventories from 1989 and 1994 (polygon). These data layers can be viewed with the ArcExplorer software provided on the CD-ROM or with ArcView software if it is available to the user.

There are many advantages to putting data into a GIS: It allows the user to investigate the spatial array of data; data can be manipulated by overlaying data layers and performing queries; the panning and zooming functions of GIS software allow the user to focus on particular areas of interest; additional, specialized customizations of the software allow the user increased analytical techniques and abilities. GIS software also provides the user with the ability to create maps displaying any combination of the data layers desired. These maps can be saved in digital form or can be printed out as hard copy. In addition, the user can modify the provided ACE Basin ArcView Project by adding or removing data layers, creating new views or layouts, and organizing view coverages or similar subject matter in a single view.

GIS will facilitate learning by allowing students of all levels to manipulate data in queries. Land use managers can use it to make management decisions. Scientists can use it to look for areas where historical studies have been done and where new studies are most needed. The GIS database can be added to existing databases or can be supplemented in the future to make a more comprehensive database. The dynamic qualities of a GIS open up numerous possibilities to its users.