7832

• UCREFRP Catalog Number: 7832
• Author: U.S. Bureau of Reclamation.
• Title: A Pilot For Long-Term Monitoring Of Resources On The Colorado River In The Grand Canyon Using Geographic Information Systems.
• USFW Year: 1995.
• USFW - Doc Type: \
• Copyright Material: NO

To establish integration protocols, a pilot study of GIS site No. 4 was completed. This effort
defined the parameters involved in generating a 1990 data base of medium resolution
hydrological, biological, and geological data (Bureau Of Reclamation, 1993). This effort
established the methodology needed to develop the base data described further in this section
and prompted the development and implementation of the "Glen Canyon Environmental Studies
Geographic Information System Information Guide and Operating Protocol."
The protocol was generated to provide guidance to all GCES researchers and data base
developers and as a template for data integration. A short-term objective of the data
management program was to ensure that data collected under the GCES program are not lost
as the .initial research studies are completed. By establishing metadata (data about data),
cooperating agencies' roles and responsibilities, GCES research trip checklists, ground control
requirements, and data exchange standards were set to ensure that the data developed for
GCES will be valid and viable. The "Glen Canyon Environmental Studies Geographic
Information System Information Guide and Operating Protocol" is located in appendix B.
Methodology
To standardize the study area being mapped, field work for the monitoring sites was completed
during the scientific low flow of 5,000 ft3/s in 1990.
The 1990 CIR photographs, enlarged from 1:4,800 to 1:2,400 scale (with registered mylar
overlays), were used in the field, which defined classes of hydrological, biological, geological,
archeological, and cultural features. These features are mapped on the registered mylar
overlays using a mylar pencil. The classification scheme and definitions can be found in
appendixes C and D. Classes were delineated on each photo within the monitoring site from the
top of the old high water zone down to the Colorado River. The interpreted mylars were then
quality checked in the field for consistency and accuracy in the mapping. The mylar overlays
are used as templates to classify and map information from the 1:2,400 orthophoto base map
product. After the template was completed, the data were transferred from the CIR
photographs to the georeferenced orthophoto base maps.
A mylar overlay was affixed to the orthophoto grid and registered by drafting the 200-m Arizona
State Plane grid tics, represented on the orthophoto, with a 0.012-in-wide drafting pen. The
orthophoto grid was placed over the classification template, and all identified classes were
drafted to the registered overlay as depicted on the orthophoto, allowing for georeferencing and
rectification of the spatial data. Orthophotos are geometrically equivalent to conventional line
and symbol planimetric maps and show true orthographic positions of objects. Because they are
planimetrically correct, orthophotos can be used as maps for making direct measurements of
distances, angles, positions, and areas without making corrections for image displacements
(Wolf, 1974). The registered overlay was then scanned and brought into the georeferenced
GCES/GIS data base.
Using the defined methodology, the geological, hydrological, and biological base data developed
for the long-term monitoring program have a horizontal accuracy of 2.0 in and a vertical
accuracy of 1.0 in. Contributing scientists can use this methodology in the generation of their
data sets.
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