A GAS Conversion Experience
Patrick Dolan
South Carolina Electric and Gas
440 Knox Abbott Drive, Suite 550, Cayce, South Carolina, 29033
Chris Deasy
Cartotech, Inc.
11900 Crownpoint Drive, Suite 100, San Antonio, Texas, 78233-5349
Abstract
South Carolina Electric and Gas (SCEC%G) and Cartotech, Inc. will discuss the user and vendor
perspectives regarding planning, implementing and monitoring the conversion of the Charleston
Division gas mains and appurtenances. Focal points of the presentation will be the pilot project,
legacy data, multiple scale products and areas targeted for improvement, based on statistical data.
SCE&G will review the user’s struggles relating to the quality of SCE&G’s legacy data. The
legacy data challenges include matching map records with corresponding mainframe records,
mapping at multiple scales from one data set and defining operational wants versus needs during
the start-up period. SCE&G will also discuss how they maintained a parallel system of manually
drafted updates while tracking those changes concurrently with the conversion process to be
added to the database post conversion. Cartotech will also address the conversion contractor’s
perspective of planning, implementing and monitoring SCE&G’s gas conversion project. This
portion of the paper will address the uniquely challenging aspects of this conversion project.
Cartotech will discuss targeted improvement areas based on results of quality assurance statistics
and how those results will be applied to enhance the process for the remainder of conversion.
Both companies will address the importance of the client-vendor relationship and the teamwork
required to have a successful conversion project.
In the Beginning
In 1993 the Gas Strategic Business Unit (SBU) of South Carolina Electric and Gas began the
implementation of a Geographic Information System (GIS). This was in response to the critical
issues outlined in the Gas SBU Five Year Business Plan, which stated that the goal of being
recognized “by our customers as the most competitive gas company in the Southeast, in terms of
price and quality of service.” To achieve this goal, the Gas GIS team decided to focus on using
GIS technologies for Gas Operations. The goals of the GIS project were to provide our
technicians maintenance capabilities for the gas distribution system, provide our engineers
modeling capabilities, and finally, to build a foundation for other information systems through a
common geographical link.
Step One
The first step for the Gas GIS team was to assess the “health” of the source data. To accomplish
this, the source data was divided into two categories, 1) source maps, and 2) legacy mainframe
data.
Source Maps
Gas Operations normally deal with five map types for its distribution system. These include
system facilities/grid maps, town maps, network maps, sectional maps, and valve reference
maps; all of which were maintained by a centralized drafting department. It was determined that
the basis for conversion would be the system facilities/grid maps. To assess the condition of
these data sets, a map inventory took place. The inventory was designed to determine what
mapping consistency existed between the four Gas Divisions, the level of detail being mapped
and what anomalies occurred on the source maps.
Legacy Mainframe Data
The legacy data contains information on facilities such as valves, regulating stations, pipes and
cathodic protection devices. The goal of examining this data was to determine if any
discrepancies between the mainframe records and source maps existed. If any were found,
Operations personnel would resolve them prior to conversion.
Clean up Process
Once the source map inventory was completed and mainframe match up was final, the Gas GIS
team identified three major issues that needed to be resolved before conversion could begin. This
included equipment location dimensioning, source map to legacy records linkage and map
updates for Operations.
Equipment Location Dimensioning
The first major issue identified was location dimensioning. The source maps were littered with a
variety of different types of dimensions. Dimensions were measured from building footprints,
valve boxes, centerlines, right-of-ways, street intersections, trees and utility poles. However, it
was important to determine which of these measurements were the most accurate and necessary
for the users in the field. It was equally important to determine a consistent rule for our
conversion vendor to follow in capturing and placing these dimensions from our source maps.
Gas Operations determined that the most consistent and reliable dimensions were those
measurements taken from road centerlines and building footprints, as well as end of line
measurements.
Source Map to Legacy Mainframe Records Linkave
The second major issue identified by the Gas GIS team was the need to maintain the link
between the legacy data and the source map information so that after conversion the two sources
706?of data could be related. The current link between the two sources was based on the mapsheet
number. However, this link would be broken after conversion due to the implementation of a
new mapsheet numbering scheme. The issue was resolved by creating a new key that was stored
on both the mainframe data set and the newly converted data set from Cartotech. The result
allowed SCE&G to maintain the link between the two sources once conversion was completed
and to enable a tracking process to ensure both the mainframe and GIS data sets stayed in synch.
Map Updates for Operation
The last major issue uncovered by the Gas GIS team was the need to provide map updates to Gas
Operations. Gas Operations decided it was necessary to continue providing updated maps to the
field during conversion. The Gas GIS team devised a map freeze plan which maintained a
parallel system of manually drafted updates while tracking those changes concurrently with the
conversion process. The first step to this process was to make two photocopies of the original
source maps. One set of copies would be sent to Cartotech and the other would be stored at
SCE&G. The SCE&G copy would be red lined for all updates that occurred during conversion.
This allowed SCE&G to track facility information Cartotech was converting as well as track all
new updates. These maps were then photocopied and sent out to Operations as their updated
source maps. Once conversion was completed, the SCE&G source maps were used as a training
tool for Gas Operations by having the technicians add the red lined updates to the GIS database
after conversion.
Pilot Project
Everything we had to do Before We could start
Prior to beginning the pilot project, SCE&G had accomplished many of the prerequisites
regarding a conversion project. Those accomplishments included: a risk analysis, costlbenefit
analysis, a theoretical plan addressing the inter-relationship between Operations/Work
Management and Customer Information System/Accounting, a resource requirement evaluation,
management’s support, proof of concept testing, well-defined project expectations and identified
areas of potential concern. It took both the utility and the vendor, working as a team,
approximately one full year to accomplish these tasks.
Beginning the Pilot
Now that it seemed we had all our ducks in a row, it was time to test our plan. We chose the most
challenging area based on map congestion, an average representation of mapping standards, and
the oldest legacy data set as our pilot area. Based on this criteria, the Gas GIS team decided on
the peninsula of Charleston. It was made up of fourteen map sheets which consisted of 102 miles
of main and 451 valves. Before sending these maps to Cartotech, a preliminary conversion
specification was written to guide Cartotech on what SCE&G needed to be converted for the
pilot. This simple conversion specification later became our foundation for the database design as
well as final conversion specification guide. The only constraint placed on the pilot was that it
needed to be completed within twelve months.
The Twelve Months of Pilot
During those twelve months of the pilot, the Gas GIS team and Cartotech learned a tremendous
amount about what the critical issues would be once conversion started. The pilot project gave
SCE&G the opportunity to prototype their applications and build their Quality Assurance/
Quality Control routines. Finally, h allowed Cartotech and SCE&G to build a working
relationship which would anchor the composite team throughout the conversion endeavor.
Lessons Learned form the pilot
Conversion Specifications
One of the first critical lessons SCE&G learned from the pilot was how to build a solid
conversion specification. Since Cartotech had no knowledge of the internal design and mapping
practices of Gas Operations, it became important to write a document which not only stated the
database design, but addressed placement rules, facilities to be captured and priorities to be
followed when rules conflicted. The document also created the foundation for further rule sets to
be built upon as new problems surfaced.
Capturing Key Attributes
Another lesson was the importance of focusing on the crucial elements that needed to be
addressed during conversion. One example of this was populating the correct size and material
information for mains. Since every pipe segment was not denoted with material or size, it
became critical to have Cartotech populate records only when those attributes could be
determined with certainty. Once conversion was completed, the technicians would fill in the
unknown pipe material and size. This helped ensure the integrity of the GIS database by relying
on trained personnel to provide the missing information.
