How the west was mapped - The good, the bad and the ugly
John Milligan
Navajo Tribal Utility Authority
PO Box 170
Fort Defiance, AZ 86504
Jim Nelson
Global Mapping Solutions
Cheyenne, WY
Tom Taber
Miner @ Miner Consulting Engineers, Inc.
4701 Royal Vista Circle
Fort Collins, CO 80528
Abstract
About three years ago the Navajo Tribal Utility Authority began modernization of its
operations and financial management systems. As part of this effort, we have completed
perhaps the most ambitious, innovative, and geographically extensive GPS/GIS project to
date mapping some 800,000 utility components with GPS based observations in a 26,000
square mile service area. Due to the limitations of existing GPS data collection systems a
GPS and pen based computer field data collection and software specific to our
information needs was developed for the program. Integration of the results with a new
core business system and an existing energy management system is underway.
This GIS data is maintained centrally and made available to our 8 local and remote
offices at modest cost using our microwave radio based LAN and terminal services
software. Existing raster and vector maps have been supplemented with inexpensive 1
meter and 1 foot resolution aerial photographs to provide and accurate and up to date land
base.
Our experiences, the good, the bad and the ugly, are described.
Requirements and History of the Navajo Tribal Utility Authority ( NTUA)
The Navajo Tribal Utility Authority (NTUA) is the largest Native American owned and
operated utility company in North America. It was established by the Navajo Nation in
1959 to provide electric, gas, water and wastewater service to the Navajo people. The
NTUA serves an area of about 26,000 square miles – more than many States - in the
“Four Corners” portions of Arizona, New Mexico and Utah. The NTUA employs about
500 people at its central Headquarters and seven widely dispersed regional offices. The
utility is unique in serving all utilities in an area with the near lowest population density
in the U.S. Some 33,000 electric (including 219 photovoltaic), 29,000 water and and
12,000 natural gas customers are served by about 7000 miles of electrical distribution
lines, 85 individual Public Water Supplies, 70 wastewater collection and treatment
systems, and 13 natural gas distribution systems.
Like many utilities, NTUA prepared and maintained drawings of its facilities that soon
became outdated, inaccurate, less than useful and potentially dangerous. Problems with
maintaining records were compounded by the size of the service area, the number of
remote offices and robust rate of growth. In 1990, a joint project was undertaken with
three other REA borrower utilities to develop geographic information system intended to
simplify map maintenance and dissemination, and to interface with an electrical
distribution analysis software package. The project used the ESRI software suite, which
NTUA has used since. In a few years the software development project failed. A few
staff continued in-house development of the NTUA GIS by automating as-built drawings
and geographically registering these to an in-house developed landbase with the
assistance of GPS equipment. GPS mapping of proposed facilities was done with great
benefit as well. It eventually became obvious that more focused effort would be required
to provide a system in which accurate maps and supporting records of the utilities could
be created and maintained. It would also be necessary to create and maintain accurate
maps and records.
In addition, utility modeling software packages – Stoner Synergee™ for electric systems,
GasWorks™ for natural gas systems and Cybernet™ for water and wastewater systems
had been previously acquired. These were not being used effectively because accurate
spatial data about utility system components needed to model systems correctly simply
did not exist. The potential for using the product of a GPS field data collection effort to
construct these models was recognized.
Money was budgeted and a Request for Proposal to provide what NTUA believed to be
such a system was issued in late 1999. The basic requirements were a GPS inventory of
all utility system components and supporting hardware and software. Some 185 separate
Electric circuits, Water and wastewater, and Gas systems – Poles, transformers, meters,
valves, etc., etc. were to be mapped in the field. A software system to store and maintain
the data, and permit its use for mapping, maintenance and system modeling purposes was
included as part of the RFP.
As it has turned out, about 800,000 point and line features were mapped during this
project. This required collection of about 6,000,000 items of information in the field. The
project represents the geographically most extensive inventory of which we are aware. It
is the only utility GPS project that we are aware of that set out to design the utility system
model around the possibilities and limitations of GPS data collection rather than around
conversion of paper or digital records.
More than 20 proposals with widely varying approaches to mapping and data display
management needs were received. Proposed data capture techniques ranged from some
sort of aerial image capture to survey-grade GPS mapping of individual utility system
components. Software proposals varied from out of the box use of available utility
system packages through customization of existing CAD and GIS software to
development of new, custom software. A committee comprised of engineers from each of
the utilities and a GIS/GPS specialist considered these.
In April of 2000 Global Mapping Solutions (GMS) of Cheyenne, Wyoming was awarded
the contract. GMS was to provide the GPS data collection services. GMS partnered with
Miner & Miner (M&M) of Fort Collins, Colorado to provide GPS data conversion,
Quality Analysis/Quality Control (QA/QC) and ESRI software based ArcGIS™/ArcFM™
customization services for the product of the fieldwork.
A hardware and software system consisting of 10 ArcGIS/ArcFM™ and 15 ArcView8™
licenses, three Windows based Compaq™ servers supporting the GIS software and an
Oracle™ based geodatabase was acquired to serve as the medium for the GIS. Citrix
Metaframe™ software is used to permit access to the data over the corporate WAN,
which includes a 900 MHz microwave component for the 7 remote offices.
GMS, in conjunction with Spatial Data Resources of Topeka, Kansas developed a GPS field data
collection application, FMGPS™, for the NTUA project. FMGPS was developed using ESRI’s
MapObjects™ and Trimble Toolkit™. The software allowed us to build a GPS data collection
system around the framework of the existing ESRI and Arc-FM data models, permitting smooth
conversion of field data into ArcFM. Simply put, this software allows the operator to map and
describe utility systems directly in the field rather than by collecting points (like poles or valves)
in the field, then having someone else connect the dots (generally incorrectly in NTUAs
experience) in the office. Past experience lead to our placing a great deal of value on being able to
construct geometric networks such as pipes correctly in the field rather than in the office. It
proved possible, with proper preparation, to collect more information about utility systems on the
ground than it would have been to reconstruct them from records, even if accurate records had
existed.
