This is a final release version of the layer. All Standard Operating Procedures have been adhered to and the layer has been subjected to quality assurance and quality control. The best available data sources were used to map LULC, but no detailed accuracy assessment was performed.
The minimum mapping unit (MMU) for all features is approximately 0.1 hectares. Features small than the MMU were grouped with surrounding features. The 800 meter buffer is measured from the stream's banks when they are visible from aerial imagery, and from the stream's centerlines for those streams whose banks are not visible.
The Vermont Mapping Program's (VMP) 0.5m 1:5000 panchromatic aerial digital orthophotographs served as the primary mapping source. Due to the fact that the VMP orthophotographs were outdated, photointerpretation was supplemented using the USDA's 2003 1m color digital orthophotographs gathered as part of the National Agricultural Imagery Program (NAIP). NAIP orthos have a lower spatial accuracy (approximately 1:40,000 scale) when compared to VMP orthos and were only used as the primary mapping source in those cases where the NAIP reflected more up to date information (a river changing course for example). Thus, this stream corridor LULC layer should be considered accurate to a scale of 1:5000 and current as of August/September 2003. LULC class assignment was primarily based on analyst recognition and photointerpretation keys. To aid in interpretation ancillary data layers were used including: E911 road centerlines, driveway centerlines, and housing points (urban features); USDA Common Land Unit (CLU) polygons (agricultural features, particularly hay/crop fields); NRCS soils inventory hydric soils polygons (possible presence of wetlands); Vermont Significant Wetlands Inventory data (wetland locations); and Mineral Resource Data Systems points (locations of mines, quarries, and gravel pits).
Please refer to the 'Supplementary Information" section of the metadata for more information on the history of the project.
Please refer to the project's web site (<http://www.uvm.edu/~joneildu/LULC/>) for data downloads, documentation, and photointerpretation keys.
Urban-General (1): Developed areas of intensive use with much of the land covered by structures. Included in the mapping of urban land is all developed land including such features as lawns and golf courses. Structures on agricultural land are included in this class. Urban-Transportation (14): principally roads, are mapped as a code 14. Agriculture-General (20): Land that is primarily pasture or managed for some other agricultural use, but not hay, crops, orchards, berries, ornamentals, or tree farms. Idle agricultural land is given a code of 2 unless shrubs are established, in which case it is assigned to brush (3). Agriculture-General (21): Fields containing either hay or row crops (typically corn in VT). Hay and corn are often in some type of rotational planting in VT. Agriculture-Orchards (22): Orchards, berry farms, tree farms, vineyards, and ornamental horticulture. Brush (3): Features are typically those areas that are in transition from agriculture (2) to forest (4). Shrub/scrub wetlands are assigned to the scrub-shrub wetland class (624). Forest-Deciduous (41): >= 70% broadleaf tree species; >80% canopy cover. Forest-Coniferous (42): >= 70% evergreen tree species; >80% canopy cover. Forest-Mixed (43): A combination of broadleaf and evergreen tree specie ; >10% canopy cover. Water (5): All water features, aside from swimming pools and detention ponds. Wetlands-Forested (61): Wetlands with >80% canopy cover. Wetlands-Emergent (623): Non-forested wetlands with low-lying emergent vegetation. Wetlands-Scrub/Shrub (624): Non-forested wetlands with scrub/shrub vegetation. Barren (7): Non-urban features devoid of vegetation such as mines, gravel pits, and quarries.