Making a GIT Tossed Salad - Cost Sharing Opportunities Between Government and Utilities
John A. Middlestead
Manager, Distribution Drafting & MARS Technical Services
Michigan Consolidated Gas (MichCon), 3200 Hobson
Detroit, Michigan 48201 USA
Understanding the Ingredients Needed to Make a GIT Salad
Just like the vast variety of salad recipes we can all select from, government and utilities
have mixture of geospatial information & technology (GIT) ingredients that they require
or put into the design mix. Understanding the different needs and expectations between
government and utilities / telecommunications / other companies, is the first step to
developing a "lowest common denominator". Government, it could be argued, has a
wider variety of needs for a geographic information system (GIS) than does a utility.
Since government is made up of a many different departments, each with their own
unique requirements, it is difficult for the agency in its totality to come to a common
agreement let alone working with outside companies.
To understand how diverse GIS's have become one only needs to go to the Web and
search under "Geographic Information Systems". Hundreds of web sites are available for
review. It is not hard to see how government has used the technology creatively to
address a magnitude of issues. Crime statistics, environmental issues, land use zoning,
tax assessment and valuation, E911 vehicle routing, school district boundary setting and
busing analysis based on student population shifts, soil mapping, police and fire coverage
/ statistics, etc. These are all in addition to public works applications such as road
construction and maintenance, sewers, signage and lights. Whenever one talks to
governmental agencies there are issues of land base accuracy, including required
photography and planimetric, cadastral and cultural land captured features, etc. The
understanding of exponential cost increases based on increased land feature /
photographic accuracy is not always understood until the bids arrive. Even then, based
on perceived requirements by various individuals, some will hold out until monies are
available for the accuracy they demand. Obviously, in today's day and age, something is
better than nothing for governmental agencies and utilities verses waiting for the perfect
solution at next to no cost.
An electric, gas, water, pipeline or telecommunication company has differing needs as
well. Above ground facilities do not require as much location accuracy as below ground
facilities, both from a land base and facilities standpoint. Land is almost a necessary evil
to many companies while tracking assets is critical. As a result, great debates have
occurred regarding land base accuracy requirements between utilities.
For below grade utilities it is critical that the facilities be located off of a right-of-way /
property line or edge of pavement with an accurate dimension noted on the GIS. Land
accuracy is important with below grade utilities. The question is how far to go with the
accuracy requirement. When it comes to facility placement, most below grade utilities
utilize a fairly accurate land base and "relative" accuracy for facilities. The most
common reason for relative accuracy is the inherent over-plotting of facility data that can
occur with detailed mapping. The accuracy of land base becomes even more important to
utilities and telecommunication companies when their GIS is tied to a work management
system (WMS). This is due to using the GIS for "points and spans" design and cost
estimating. The more accurate the land base and facility placement, the more accurate
the construction cost estimate.
What Is Common to the GIT Salad
- Aerial Photography / Imagery
Sometimes a common requirement for both government and companies, although some
have elected not to develop their landbase from scratch but rather jointly develop or
purchase from an outside firm / vendor. With data storage becoming very inexpensive
some agencies and companies are electing to use digital orthophotography / imagery as a
backdrop to vector line work for facilities and limit land to street centerline, for example
- Land Base Features
Common land base features that government and companies have included in their
respective GIS's include the following. While certainly not an all-inclusive list it does
cover the many of the feature of interest. Various descriptive text along with the graphics
is part of the features.
Typically, government and utilities require some pictorial basis to locate a land feature or
facility against. Some may use an intelligent street centerline method to locate a parcel or
address. The majority of utilities will have a right-of-way and/or an edge-of-pavement
land fabric to orient their facilities against. Government always has a full set of parcels
in addition to right-of-ways to track property values and the size of each parcel. This
requirement is many times cited as why the need for +/- 2 ½ foot accuracy or better is
needed for orthophotography.
While these basic items may have some commonality,
there are differences. The main differences between government and
utility companies is that government must meet the needs of their own
departments, which in large cities is significant, as well as the
community and various businesses at-large. Land and property information
is critical for zoning, tax assessment, title searches, etc. On the flip
side, utility companies are interested in their facilities, how they are
connected and where they are located. While land information is
important to locate facilities, it is not the primary focus of a GIS.
Given the two different points-of-view one can see why it is so
difficult for reaching an agreeable partnership.
