In 1994 Colonial Gas Company began the process of automating the collection of leak detection survey data and its upload into the corporate facility database. Using digital mapping and data management software on portable computers, Colonial Gas proposed to eliminate paper maps and forms in the field and to streamline project organization, scheduling, data input, sweeping, and reporting. Costs were estimated for application design, programming, and implementation. This article examines the development and implementation of the data automation application and its utility after one year of service.

Colonial Gas is a local distribution company (LDC) serving 153,000 customers in 24 cities and towns in the Merrimack Valley of Massachusetts and on Cape Cod. In 1992, Colonial Gas launched a corporate-wide initiative to automate its facilities data by converting ink-on-mylar-based maps into georeferenced digital files. To assist in the proposed implementation of an AM/FM/GIS system, Colonial Gas contracted James W. Sewall Company of Old Town, Maine, to provide aerial photography, photogrammetric mapping, and data conversion services.

Landbase Development

During the next 6 years, Sewall digitized Colonial Gas’s existing 1” = 400’ map series, captured new aerial photography with GPS survey control, and compiled 1” = 40’ base mapping of the utility’s service area. The 1” = 400’ maps allowed for the general placement of gas mains, valves, road, and main information text. The larger-scale 1” = 40’ maps displayed landbase features in greater detail, such as building outlines and street edges. Using as- built sketches and other construction documents as references, Colonial added gas facilities, including mains, services, valves, service account numbers, service descriptors, and service valves and dimensions to these facilities. Sewall performed the data conversion on a MicroStation CAD platform. This mapping system was designed for use by facilities maintenance and construction end users.

The Walking Survey

In 1994, Colonial Gas identified the need to streamline the procedures of the walking survey, an application still dependent upon the use of hard copy maps and paper reports. In compliance with U.S. Department of Transportation regulation CFR Title 49 §192.723, Colonial Gas performs annual walking surveys to detect gas leakage from services and fittings. Carrying a flame ionization unit (FIU) equipped with sensor nozzle, a company surveyor walks the course of the gas line, “sniffing” the ground for minute amounts of methane. An inspector, usually from a third-party contractor, records the test results that are delivered to the main office for review. The regulation states that every service within an LDC’s franchise territory must be surveyed every five years if cathodically protected and every three years if not.

Design Objectives

Working closely with Sewall, Colonial Gas identified ways to address inefficiencies in the current walking survey procedures. Insufficient or nonexistent information about the location of service lines in the field often required that the surveyor conduct an exhaustive FIU sweep of the general area. What survey crews needed were accessible maps or as-built plans that clearly indicated the route of the service line. In addition, survey crews unloaded several hundred pages of paper reports for processing at the main office on a daily basis. Immediate access to data stored in digital form in a database would expedite report analysis, survey monitoring, tallying of services with detected leaks, and the development of repair crew work orders. Survey crews in the field would be equipped with small, pen-based computers with which to fill out their forms electronically. The computers would also store and display vicinity map data of the services under survey. Completed electronic forms could then be uploaded onto a database in the office, permitting office personnel to query and examine the results easily.

Application Development

In 1996, Colonial Gas contracted Sewall to develop the Walking Surveyor Assistant™, a software tool to automate the task of recording leak detection survey data. The project was originally conceived as a straightforward assembly of database files and digital mapping onto portable field computers, with data access and management provided by specialized off-the-shelf viewing software. Sewall anticipated that the primary development effort, and most of the cost, would be spent customizing the viewing software and/or the data so that they would work well together. After examining the available options, Sewall and Colonial decided to create instead a custom system from scratch, employing Internet technology in a single computer environment. Using Microsoft’s Internet Explorer™ and Personal Web Server--both available free with Windows 95--Sewall developed a Web site to be run on a single- computer intranet. Basic HTML, scripting, and third-party browser components were combined to create the final product.

Available Facilities Data

Although Colonial Gas did not have an AM/FM/GIS system in place, the utility's digital map data contained graphical links, or leash lines, between map symbology and the text annotation (Figure 1). Using the leashed account numbers in the facility maps, Sewall developed a software application in MicroStation Development Language (MDL) to automate the database linkage process. The meter linking application scanned each map file for the graphic symbols representing service meters, then linked each symbol to the record in the service database with the account number found at the end of the meter's leash.

Figure 1: Data Manager to control the input of survey data and the viewing of maps

Available Hardware

The Walking Surveyor Assistant™ was designed to reside in part on two computers: a Hammerhead™ pen-based computer used in the field to locate services and collect data, and the central office computer, which hosted Colonial’s Oracle database. Development was performed on a MicroSlate pen-based computer.

Software Components

The Data Manager, the field computer portion, provides the user an interface to control the input of survey data and the viewing of the maps which reside on the computer’s hard disk drive (see Figure 1). Using Microsoft’s Internet Explorer as a host shell and operating from within this browser application, the Data Manager is launched at the survey site. A third-party ActiveX component module developed by Pangaea CAD Solutions is included as a browser plug-in to enable viewing of map files in their native MicroStation DGN format (Figure 2). The File Manager, the central office portion of the application, provides tools for querying Colonial’s survey database, downloading and uploading data, updating files, and reporting (Figure 3). A self-contained application, the File Manager operates on a WindowsNT™ network. Through the File Manager interface, Colonial’s survey team can download data on specific services to the field computer following a query of the interim survey database. Maps are updated via a locally licensed copy of MicroStation.

Figure 2: Walking Surveyor Assistant(tm) Map Viewer Window with Controls

Figure 3: File Manager Interface

Hierarchical Tree Control

To allow the user to select the service being surveyed, a hierarchical tree control was implemented (Figure 4). The top level of the tree contains the towns; the next level contains street names within the parent town, and the bottom level contains address numbers, on the parent street, of services not yet surveyed. When the user selects a street node, a query for the addresses belonging to that street is submitted to the server. Because tens of thousands of addresses are often stored in the field computer’s database, populating the tree at the start of the application is usually too time consuming. This method saves a significant amount of processing time and keeps the collection of nodes maintained in memory to a reasonable number. In the address selection process, the user can select an icon to display a map centered on the meter cell connected to the address. Tools are available to zoom and pan the area (see Figure 2).

Figure 4: Hierarchical Tree Control for Address Selection

Walking Survey Form

The walking survey test results form consists of a number of multiple choice fields (Figure 5). The set of possible answers for most of the fields is small enough to allow use of radio button controls for the result selection. Other fields, for which the set of values is queried from the database, are represented as drop down menu controls, manipulated by mouse clicks. When all the required fields in the survey form are filled in, a check box appears at the bottom for the user to affirm that the survey for that service is complete. The user then submits the data in the completed survey to the database.

Figure 5: Walking Survey Test Results Form

System Implementation

The Walking Surveyor Assistant™ was implemented in early 1998. Training the walking survey crews to use the Internet user interface required only a few hours. The computer administrator, in effect an Internet server administrator, needed instruction in the maintenance of the application and continued user support throughout the season.

One-Year Review

Colonial Gas used the Walking Surveyor Assistant™ successfully during the 1998 survey season and summarized the results of this use as follows:

1. Automating the walking survey eliminated paper maps to locate facilities and reduced the amount of “sweeping” of a service area necessary to complete the survey. A paper recording of any leaks was still performed along with a paper sketch of its location.
   
2. Scheduling, data input, and reporting processes were streamlined with measured efficiency gains.
   
3. Without default results, data entry times took longer, which had both a negative and positive effect. On the negative side, it could be safely assumed that most results would be similar to all other services surveyed. Thus it would have been easier and faster for the surveyor to respond to the exceptions only. On the positive side, no entry was taken for granted; therefore, nothing was overlooked.
   
4. The increase in the number and quality of reports from this system helped Colonial increase control of maintenance activities resulting from leak detection surveys. Due to the implementation of the Walking Surveyor Assistant™, maintenance requests were passed to the work management system more efficiently and a stricter command was placed on managing the survey.

Reference

Department of Transportation (1995). Pipeline Safety Regulations - Parts 190-199, p. 436.

Additional Information:
Brent A. Jones, PE, PLS
Vice President, Energy and Telecommunications
147 Center Street, P.O. Box 433
Old Town, Maine 04468
207 827 4456
bjones@jws.com

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