Geographic information system pilot project for the Upper Mississippi River System

The geographic information system pilot project on Pool 13 of the
Upper Mississippi River System was initiated to evaluate
system-wide application of various methods of capturing,
processing and converting resource data.  Classification schemes
were developed for two data themes: land cover/land use
(vegetation) and aquatic areas.  Evaluation of 1:15,000 scale
aerial photography indicated that (1) color infrared
transparencies were essential for accurately mapping major
vegetation classes and vegetation units less than 1 acre; (2)
color infrared prints were essential for field work (delineating
work areas on the photos and identifying in the field; (3) true
color (Ektachrome) transparencies and prints were not useful
vegetation types in mapping the land cover/land use or aquatic
areas themes; and (4) black and white infrared prints were useful
for identifying water regimes in the land cover/land use theme but
were not useful for identifying vegetation types or aquatic areas. 
The 1:15,000 scale photography provided the detail needed for site
specific mapping and was useful for mapping general features. 
Automated procedures were developed to produce the aquatic areas
coverage from the land cover/land use coverage created in the
ARC/INFO geographic information system,  which saved manual photo
interpretation and drafting time.  The conventional three step
process of manual photo interpretation, drafting and digitizing
provided more accurate mapping of complex data themes compared to
digital image processing.  Image processing technology requires
further improvements before it is suitable for high resolution
mapping over large areas.  Manual digitizing was more accurate and
economical than a scan digitizing process used to capture thematic
data.  However, evaluation of other scanning technologies is
recommended for future Upper Mississippi River System mapping
efforts because the technology continues to improve in quality and
accuracy, while cost steadily decreases.  Lookup tables and macros
were developed for converting ARC/INFO data into two other
geographic information system formats: EPPL-7 (PC based version of
the Environmental Planning and Programming Language developed by
the Minnesota State Planning Agency) and GRASS (Geographic
Resources Analysis Support System developed by the U.S. Army Corps
of Engineers Construction Engineering Research Laboratory).