Coastal Resources Projects
The “Alabama Comprehensive GIS Inventory of Coastal Resources” was developed as part of the Coastal Impact Assistance Program. The purpose of this project was to compile and disseminate a comprehensive GIS inventory of Alabama’s coastal area resources designed to facilitate the planning/management, protection, and conservation of the coastal area by providing readily accessible GIS information. GIS thematic layers are supported by metadata that are Federal Geographic Data Committee (FGDC)-compliant to specifications detailed in the Content Standard for Digital Geospatial Metadata (CSDGM; FGDC-STD-001-1998; http://www.fgdc.gov/metadata/contstan.html).
In collaboration with the Alabama Emergency Management Agency (AEMA), the Coastal Resources Section developed the “Alabama Metadata Portal,” an internet-based tool for the discovery and distribution of Alabama geospatial data. This platform allows the GSA to better organize existing GIS data, obtain new data from outside resources, and disseminate GIS project deliverables. It also supports collaboration between other stakeholders for the publishing and sharing of data relevant to Alabama. The “Alabama Metadata Portal” allows users to search databases by time period, keywords, and location. In addition to the portal, the GSA is also a node on the National Geospatial Data Clearinghouse using the Z39.50 compliant Isite module server application.
The most recent of several projects completed using satellite imagery have included an impervious surface mapping project and a land-use/land-cover project completed in 2003 and 2006, respectively. Each project employed 2000 Landsat 7 Enhanced Thematic Mapper Plus satellite imagery with 30-meter spatial resolution as the primary data set. Impervious surfaces were mapped suitable for 5-acre-scale use and validated using the results from three subwatersheds mapped with conventional aerial photography. Land-use was similarly mapped; however, supervised and unsupervised analyses resulted in the classifications: barren ground, mixed forest, evergreen forest, agriculture/grass, developed, wetland, and water. GSA anticipates using higher resolution data and subpixel spectral analysis to further refine land use and establish change detection.
Present priorities include the implementation of new techniques to ease workloads and increase output and to promote the compatibility and dissemination of data between other data acquisition groups.
USGS, NASA, and the US Army Corps of Engineers are using airborne laser mapping systems to survey coastal areas before and after hurricanes. As the aircraft flies along the coast, a laser altimeter (LIDAR) scans a several-hundred-meter-wide swath of the earth's surface acquiring an estimate of ground elevation approximately every square meter. Coastal Resources Section is currently creating enhanced digital elevation models from LIDAR datasets. We are using 3-D GIS technology in the processing, analysis and visualization of spatiotemporal elevation data. The goal is to evaluate the spatial distribution of sand erosion/deposition caused by hurricanes impacting the Alabama coastline. Some sample analyses are provided below.
Fort Morgan, Baldwin County, Sample Area