Page 10 - Tennessee 811 Magazine 2021 Issue 2

GIS: The Backbone of a One-Call System
By Meaghan Feeney, GIS Specialist, and Bill H Berzins, Director of IT/GIS, Tennessee 811
ow we use GIS as a one-call system:
8 • Tennessee811
2021, Issue 2
A Geographic Information System (GIS) is a computer system that analyzes and displays geographically referenced information. We use GIS to maintain member utility databases, or coverage areas, for the purposes of our locate-request-taking-software: “GeoCall”. GeoCall is integrated with GIS and because
of this, GeoCall allows us to notify member utilities that have underground services within an area of proposed excavation. When the area of excavation is marked on the map within GeoCall, an analysis is completed in the backend of the software to create a list
of member utilities to be notified within that marked area.
What makes a good utility database and what are some things to avoid?
GeoCall requires GIS data to be in
shapefile format with WGS84 projection (a mathematical representation of the Earth used to reference points). Of course, we know not everyone works with the same format and projection we do. We can convert from other formats and reproject data for a member, but it is ideal to receive member databases already converted.
One new item that we have been working on within TN811 and GeoCall is a “zero buffer”.
The more changes we must make to a member’s database, the greater the margin of error. That margin of error can make the difference in not receiving a ticket that you should have or receiving an unnecessary notification for overhead lines. One potential cause of error is sending files that represent more than just the underground components of your utility system that you want to be notified for. We’re happy to help and provide guidance as needed, but a member utility
is ultimately responsible for deciding what should, or should not, be included in their coverage area.