from CENCR, digitized from 1:24,000-scale maps
Base map data
A search was made among the Corps Districts
and imported into ARC/INFO. The county boun-
and other agencies to find digital data already pro-
daries for the Mississippi River database were
cessed. Three sources of data were found for the
acquired from the ARCUSA 1:2,000,000-scale data-
seven reaches of river: the U.S. Fish and Wildlife
base (ESRI 1993). Although these data were de-
Service Environmental Management Technical
rived from a map of much smaller scale, they
Center (USFWS EMTC), Onalaska, Wisconsin, the
U.S. Army Corps of Engineers District (CEMRO),
They were not used in the map making process.
Omaha, Nebraska, and the U.S. Army Corps of En-
The Mississippi River database covers all
gineers District (CENCR), Rock Island, Illinois.
1:24,000 USGS quadrangles adjacent to the river
between St. Paul, Minnesota, and Cairo, Illinois.
Illinois and Mississippi rivers
The counties listed in Table 2 are covered either
The USFWS EMTC provided data derived from
completely or partially by the database. This reach
the U.S. Geological Survey (USGS) 1:100,000-scale
of river is in UTM zones 15 and 16.
Digital Line Graphs (DLG) (USGS 1989) for the
The Illinois River database covers all 1:24,000
Mississippi River and for the Illinois River. The
USGS quadrangles adjacent to the river between
data were supplied in separate ARC/INFO cover-
Valley City, Illinois, and the confluence with the
ages for the roads, railroads and hydrography
Mississippi River. The following counties are cov-
present in the 1:24,000-scale USGS quadrangles ad-
ered either completely or partially by the data-
jacent to the two rivers. A coverage containing the
base: Calhoun, Greene, Jersey, Pike and Scott. This
reach of river is in UTM zone 15.
All coverages were received in the UTM projec-
Des Moines, Grand, Kansas, Missouri
tion for zone 15 based on the North American Da-
and Republican rivers
tum of 1927 (NAD27). At the RSGISC, all data were
CEMRO provided digital data for the Des
imported into ARC/INFO and projected into the
Moines, Grand, Kansas, Missouri and Republican
actual UTM zones based on NAD83.
rivers from the U.S. Census Bureau Topologically
The data received from the USFWS EMTC did
Integrated Geographic Encoding and Referencing
(TIGER) database (U.S. Census Bureau 1991). The
sissippi and the Illinois rivers. The county bound-
data in the 1990 TIGER/Line files are based on the
aries for the Illinois River database were acquired
USGS 1:100,000-scale maps and the Census Bur-
eau's 1980 GBF/DIME files. ARC/INFO coverages
for county boundaries, roads, railroads and
Table 2. Counties along the Mississippi River
covered completely or partially by the spatial da-
hydrography were supplied by CEMRO for each
county along the rivers.
CEMRO extracted the coverages from the
TIGER/Line file database and projected the data
into the State Plane (feet) coordinate system based
on the NAD83, with the exception of the Nebraska
counties, which were left in NAD27. At the RS-
GISC, all data were imported into ARC/INFO and
projected into the UTM coordinate system.
The Missouri River database covers 46 counties
between Sioux City, Iowa, and the confluence
with the Mississippi River near St. Louis, Missouri
(Table 3). This reach of river is in UTM zones 14
The Des Moines River database covered the fol-
St. Louis City
lowing counties between Boone, Iowa, and St.
Louis, Missouri: Boone, Dallas, Davis, Lee, Ma-
haska, Marion, Polk, Van Buren, Wapello and
Warren. The region is in UTM zone 15.
The Kansas River database covers the follow-
ing Kansas counties: Douglas, Geary, Jackson, Jef-