Data Dictionary for

EVSC 362 - STATES homework project datasets

David Richardson, Instructor

Summer 2007

The following datasets are available for students of EVSC 362 : GIS Methods to use as part of their class homework projects. The filename and format of each dataset along with a brief metadata description of the contents is provided. See the metadata associated with each individual file, or additional included text files, for more information.

List of Datasets and their File Formats

eusstates - shapefile

euscounties - shapefile

usgs75quads - shapefile

eusgtopo30 - ArcInfo raster Grid

bef_boxll83.e00 - ArcInfo export file

mlbs_boxll83.e00 - ArcInfo export file

vcr_boxll83.e00 - ArcInfo export file

Projection Information

All datasets in this STATES collection are in the same horizontal coordinate system using identical projections and spheroid models. This coordinate/projection/spheroid system is:

Projection: Geographic (lat./lon.) with units of decimal degrees

Spheroid: GRS80 - Geodetic Reference System 80

Datum: NAD83 - North American Datum 1983

Dataset Descriptions

eusstates - shapefile

This dataset was created from the "statesp020" state boundary polygon shapefile acquired from the USGS <http://nationalatlas.gov/atlasftp.html>, which is based on 1:2,000,000-scale state boundaries of each state from USGS Digital Line Graph (DLG) data. The statesp020 shapefile was then clipped to include only those eastern states that fell within a box with the following geographic extent / bounding coordinates : -93.0° (W), 23.0° (N) to -66.0° (W), 49.0° (N). See online metadata at the website listed above, or the statesp020.txt file included with the dataset, for more information about the source file(s).

Additional Attributes:

state : state name [text string]

state_FIPS : FIPS (Federal Information Processing Standard) state code # [integer, width 2]

statesp020 : internal USGS feature id# from originating dataset [integer, width 11]

euscounties - shapefile

This dataset was created from the "countyp020" state county boundary polygon shapefile acquired from the USGS <http://nationalatlas.gov/atlasftp.html>, which is based on 1:2,000,000-scale state and county boundaries of each state from USGS Digital Line Graph (DLG) data. The countyp020 shapefile was then clipped to include all the counties of only those eastern states that fell within a box with the following geographic extent / bounding coordinates : -93.0° (W), 23.0° (N) to -66.0° (W), 49.0° (N) - see eusstates metadata above. See online metadata at the website listed above, or the countyp020.txt file included with the dataset, for more information about the source file(s).

Additional Attributes:

state : state name [text string]

county : county name [text string]

state_FIPS : FIPS (Federal Information Processing Standard) state code # [integer, width 2]

FIPS : FIPS zone # (1st two digits = state code, last three digits = county code)

[integer, width 5]

countyp020 : internal USGS feature id# from originating dataset [integer, width 11]

square_mil : polygon area in square miles

usgs75quads - shapefile

This dataset contains the boundaries and quad names for each USGS 1:24,000-scale 7.5 minute quadrangle in the United States (includes Hawaii but excludes Alaska which has only 1:63,360-scale and larger quadrangles produced by USGS). Shapefile data ("24kgrid.shp") was acquired from GeoCommunity website <http://data.geocomm.com/quadindex/> and renamed but otherwise unaltered.

Additional Attributes:

name : quadrangle name [text string, width 30]

state : state abbreviation [text string, width 2]

lat : latitude (decimal degrees) of the lower right (SE) corner of the quad [number, 3 decimals]

long : longitude (decimal degrees) of the lower right (SE) corner of the quad [number, 3 decimals]

mrc : internal source id code [text string]

eusgtopo30 - ArcInfo raster Grid

This dataset was created by clipping the GTOPO30 global digital elevation model (DEM) dataset obtained from the U.S. Geological Survey's EROS Data Center <http://edc.usgs.gov/ products/elevation/gtopo30/gtopo30.html>. The grid cells have a resolution of 30-arc seconds, or 0.008333333333333 degrees (approximately 1 kilometer). Data was clipped to include only those areas falling within the same geographic extent / bounding coordinates used to clip the eusstates and euscounties datasets described above: -93.0° (W), 23.0° (N) to -66.0° (W), 49.0° (N). The resulting grid contains 3240(x) x 3060(y) cells. Vertical elevations are in meters above mean sea level, with the minimum elevation of coastal areas set equal to 1m. Ocean elevations are set as nodata values of -9999. See online metadata at the website listed above, or the GTOPO30readme.doc file included with the dataset, for more information about the source file(s).

bef_boxll83.e00 - ArcInfo export file

This dataset was created by reprojecting the befregboxspn and blandy_bnd ArcInfo coverages (See BEF Data Dictionary for more details) from the VA state plane north (meters) coordinate system into the geographic (decimal degrees) coordinate system, and then combining the two coverages into a single coverage so as to include the "regional" study area box comprising the nine USGS 7.5 minutes quads surrounding Blandy with the Blandy property boundaries as an internal polygon. There are no important additional attributes, just the shapes themselves.

mlbs_boxll83.e00 - ArcInfo export file

This dataset was created by reprojecting the quadclip_u83 ArcInfo coverage and mlbsproperty2 shapefile (See MLBS Data Dictionary for more details) from the UTM zone 17 (meters) coordinate system into the geographic (decimal degrees) coordinate system, converting the mlbsproperty2 shapefile to an ArcInfo coverage, and then combining the two coverages into a single coverage so as to include the "regional" study area box comprising the six USGS 7.5 minutes quads surrounding MLBS with the MLBS property boundaries as an internal polygon. There are no important additional attributes, just the shapes themselves.

vcr_boxll83.e00 - ArcInfo export file

This dataset was created by reprojecting the shoreboxu83 ArcInfo coverage and hogu83 shapefile (See VCR Data Dictionary for more details) from the UTM zone 18 (meters) coordinate system into the geographic (decimal degrees) coordinate system, and then combining the two coverages into a single coverage so as to include the "regional" study area box enclosing the Virginia Eastern Shore (comprising a 7x8 block of USGS 7.5 minutes quads covering Accomack and Northhampton counties) with the outline polygon of Hog Island (as extracted from the shore91u83 coverage) as an internal polygon. There are no important additional attributes, just the shapes themselves.