Static Maps: Digital Tidal Marsh Inventory (TMI) Description and Disclaimer
Beginning in the 1970s, the VIMS Wetlands Advisory Program started mapping all tidal wetlands in support of the Virginia Wetlands Act which was passed in 1972. USGS 7.5 minute topographic maps, and aerial photography provided geographic boundaries for the wetlands. Each wetland site was visited in the field, and analyzed for community composition. Composition was based on estimated percent cover of wetland species observed during site visits. Each wetland was also assigned one of the 17 community types outlined in the Virginia Marine Resources Commission, Wetlands Guidelines (VMRC, 1993), prepared by VIMS.
Work on developing the Tidal Marsh Inventories (TMIs) continued through the 1990s, with publications on a county by county basis. Most of these reports can now be downloaded from the web. In 1990, a large scale effort within the Comprehensive Coastal Inventory Program (CCI) digitzed all marshes delineated in the Tidal Marsh Inventory Series.
Marsh boundaries were drafted to stable-base mylar, 1;24,000 scale, USGS topographic quadrangles. They were digitized on a Numonics 2200 digitizing tablet using ESRI's ArcInfo® software. As part of quality control, the individual coverages were later edge-matched to create one seamless coverage. Since then, the coverages have been converted to shapefiles. The metadata files are included with the zipped package.
The TMI shapefile is a product of the Comprehensive Coastal Inventory Program. The metadata file which accompanies this file defines attribute accuracy, data development, and any use restrictions which pertain to the data. The data can be downloaded at this site. In doing so, the users agree to all conditions outlined in the disclaimer.
CCI is working to update the Tidal Marsh Inventory using high resolution aerial photography and ground-truthing.
Visit this site for UPDATED localities as they become available
Disclaimer for Digital Tidal Marsh Inventories
The Comprehensive Coastal Inventory Program (CCI) provides these data with the understanding that it is not guaranteed to be correct or complete, and conclusions drawn from the data set are the sole responsibility of the user.
Every attempt has been made to ensure that these data and the documentation are reliable and accurate. Neither CCI, nor the Virginia Institute of Marine Science (VIMS) assumes liability for any damages caused by inaccuracies in the data or documentation, or as a result of failure of the data to perform in a particular manner. CCI and VIMS make no warranty, express or implied, as to the accuracy, completeness, or utility of this information, nor does the fact of distribution constitute a warranty.
Individuals who download these data agree to the following, and understand the limitations defined:
Integration of these data into other products requires proper citation. Proper citation for this shapefile is:
"Center for Coastal Resources Management, Digital Tidal Marsh Inventory Series, 1992. Comprehensive Coastal Inventory Program, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Virginia, 23062."
Use of these data in map publications, either digital or hardcopy, requires proper citation, and inclusion of the CCI logo.
CCI is not responsible for misuse of these data.
CCI does not oversee or assume responsibility for alterations to this product by users.
CCI may not address specific questions from users who received the data through another party.
Distribution of these data is not restricted. CCI, however, recommends metadata file(s) always remain with the data.
CCI encourages noticeable errors be reported to CCI contact person identified in the metadata file.