Posts tagged GIS

Power Service Territories of Georgia, by Jacob Morgan

The Southern Company is one of the largest electric power utilities in the United States.  Based in Atlanta, Georgia, the company consists of five separate power companies – Alabama Power, Georgia Power, Gulf Power, Mississippi Power, and Savannah Power & Light, in addition to numerous subsidiaries involved in related industries.

Southern GIS is an enterprise geospatial services group within the Southern Company and is tasked with providing geospatial assistance to all departments in the company.  From 1999 through late 2000, I had the pleasure of working with this talented group on a variety of projects.

One such project was the creation of a Power Service Territories layer for the state of Georgia.  Georgia’s cities and counties are served by numerous municipal and rural electric cooperatives in addition to the extensive coverage provided by Georgia Power.  The state’s Public Service Commission approved these service areas and maintained the maps that laid them out.

These maps had been mylar-based up until 1999.  With the increase in deregulated services provided in addition to the core business of electric power distribution, the need for easy access to the maps became critical.  Georgia Power planned for the conversion of all of the mylar maps to a digital dataset.

The project involved scanning and digitizing information from around 159 individual maps (one for each of Georgia’s counties).

Most of the mylar maps were larger than 30 inches wide and required a wide-body scanner to be handled.  My University of Georgia friend, Jay Sellars, assisted with the scanning phase of this project.  He handled most of the scanning and quality control for that part of the project.

Once scanned, all of the digital images had to be geographically registered.  This involved comparing the images to vector road layers and selection of coincident points to setup the “warp,” or image transformation.

After registration was complete, features had to be captured from each of the images.  I did most of the digitizing in this phase, heads-up drawing polygons from each of the images into a statewide coverage (this was way before geodatabases).

Finally, all polygons were cleaned and checked for errors before being made available to other company employees.

This layer became one of the most requested datasets both inside and outside the company.  It found interest amongst most of the electric power industry in the state once completed.

Fly-map Video Image of Transmission Structure

I eventually moved to a GIS Specialist position with the Georgia Power transmission department.  I found myself planted into a huge project being undertaken at the time – the creation of a multimedia digital layer for the 16,000 mile transmission system in Georgia.

The project to collect data had been completed already.  Helicopters had flown all transmission lines and had captured video and GPS coordinates for all structures (i.e. towers, switches, substations, etc.).  (Georgia Transmission Line Mapping 2004-05 White Paper).  The output of the data was essentially a lump of files that needed to be assembled into a database and connected to geographic features.

Working through this project required lots of database manipulations, ID matching, video review (for finding structure numbers), and reconciliation of incorrect attributes.  It was very time consuming and frustrating at times, but was an opportunity to learn more about power transmission than I had ever wanted to know.

It also presented great opportunities for field work to verify data and to correct errors.

Read an article from the Atlanta Journal-Constitution on the Georgia Power transmission system control room – the bunker inside their giant black box headquarters in downtown Atlanta where the state’s power system is controlled.

Georgia Power’s Transmission Control Room, courtesy Christie Co.