Geoscience Reference
In-Depth Information
Table 10.3
Data layers and sources for the county GIS
Parcels
County auditors
Roads, railways, bike trails
ESRI, Inc. & Census TIGER files
Township boundaries
Census TIGER files
Demographic information
Census TIGER files
Soils
NRCS USDA Geospatial data gateway:
http://datagateway.nrcs.usda.gov
/
Hydrology
USGS NHD
http://nhd.usgs.gov
/
Septic tanks
County health department
Land cover
USGS/NLCD
http://www.mrlc.gov/nlcd.php
(feet) coordinate system was used with the Lambert Conformation Conic projection
and datum of NAD 83. Thus far, the epidemiological survey has been performed in
Wood, Lucas and Greene Counties.
A base map layer was the first layer to be developed and includes parcel informa-
tion, roads, railways, bike trails, schools, forests, zip codes, census tracts, township
boundaries, waste water treatment plants, sewer districts, septic tanks (if available),
soil classifications, hydrology, and hydrogeology (Table
10.3
). Multiple sources of
data were needed to collect this information including Census TIGER files, ESRI
Inc. data set, County Auditors, County Engineers, and County Health Departments.
After the base map, the permitted fields for Class B biosolids application were
added. For the epidemiological study, permitted field locations were used to gen-
erate addresses that surveys were sent to for Wood and Lucas Counties. For Greene
County, a further step was taken to attach the application information to the fields
prior to generation of the addresses. This further refined the survey results and
removed a confounding factor, a permitted field that never had biosolids applied,
from the analysis.
10.4.2 Mapping Permitted Fields
A shapefile was created to identify the location of Class B permitted fields in
each participating county. The location of Class B biosolids permitted fields (here-
inafter referred to as “permitted fields”) were collected from plat maps on file at
the Northwest District Office of the Ohio Environmental Protection Agency for
Wood and Lucas Counties and from the Dayton WWTP and local hauler for Greene
County. Polygon shapes to represent the permitted fields were initially drawn free-
hand (Fig.
10.3
). At times the description of the field was used to find the correct
location of the field when plat maps were not available. Issues with polygons were
observed such as overlapping of fields, the inclusion of forested areas and fields out-
side of parcel boundaries. A set of rules were developed to provide more accurate
