Square PEG in the Round Hole Integrating a Multiple Data Source Conversion Project
John A. Ferketic Principal, Geographic Information Systems Michael Baker Jr., Inc 770 Lynnhaven Parkway Virginia Beach, VA 23452 Matthew D. Williford Utilities AM/FM Coordinator City of Virginia Beach Engineering Department Municipal Center Virginia Beach, VA 23452
Introduction/Project Background
Virginia Beach is a coastal resort city located in the southeast corner of the state of Virginia. The City was formed in 1963 out of what was Princess Anne County. The city is bordered by the independent cities of Norfolk and Chesapeake on the West and the Chesapeake Bay and Atlantic Ocean on the North and East. The landmass covers310 square miles and is intertwined with several rivers and bay tributaries. The City provides water and sanitary sewer service to approximately 117,000 customers and has a population of over 425,000 people. The City’s Department of Public Utilities embarked on development of a AM/FM-GIS program in 1990. The Department contracted with Utility Graphics Consultants to prepare a Cost Benefit Study to assess the feasibility of implementing such a program. The report took a little over a year to complete. The results indicated that there is a definite need for the development of a new system for the graphical depiction of utility locations as well as the association of attribute data for each structure. The report also indicated that the initial cost would be high at first but that within four to five years of implementation the City would begin to see a reduction in the cost of doing business. In October of 1993, the City selected Michael Baker Jr., Inc. to develop and implement the Utility Department’s AM/FM/GIS system. Project Scope The project was separated into seven (7) main Work Tasks. It was theorized that by breaking the project into individual, independent work tasks management and administration would be more effective. Each of the tasks was assigned a dollar amount based on the complexity and work effort. A work task “Notice to Proceed” is given on an individual basis as the project progresses. All tasks are broken down into required sub-tasks. The seven Work Tasks are; Work Task 1- Consulting On-site technical and professional support throughout the period of the contract. The support includes general project assignments, project management, and coordination/facilitation of activities as related to the project and to Work Tasks (2) through (7). Work Task 2- System Plan This work task is comprised of(5) distinct sub-tasks. The primary objective is to ensure that the implementation of the computerized mapping technology would meet the City’s present and fiture needs. The sub-tasks are;
Work Task 3- System Selection Provides for assistance in selecting the most appropriate GIS hardware and software for the system. Sub-tasks were;
Work Task 4- System Implementation Items covered under this task are related to customization of the hardware and software to support recommendations/implementations of Work Tasks 1-3. The following are sub-tasks;
The Attributes Test Report is basically the same as the graphics mini test except that it validates that attribute portion of the database. One of the last steps before the final test of the Pilot is the establishment of the production procedures for capturing graphic and attribute data. This requires close examination of digital and manual source drawing information. The last step of this work task is the completion of a pilot test area. This area comprised about 1 % of the entire conversion area and its selection was based on the diversity of record drawing information that was need to test each approach fairly. The objective of the Pilot was to validate conversion procedures, applications and data collection methods prior to full-blown conversion. It also was designed to select the most cost-effective approach to be used. The “Pilot” looked at four possible approaches to conversion;
After data from all four methods of collection was analyzed, the approach that was selected was the GPS data capture and record drawing combination. All GPS collection was done so at sub-meter accuracy and provided excellent X,Y coordinate positioning for utility structures. Multipath as related to GPS collection was a concern in areas of heavy tree cover and tall buildings. The solution here was careful planning of when to collect information so as to minimize the effect. Areas that were heavily treed were put off until the winter months. Those areas that had tall buildings in close proximity to one another had a tighter window for satellite lock. Work Task 6 – Training This task involved training personnel as the project progressed through work tasks 1 -5 on use of hardware/ software applications and system maintenance. All training was geared to the different levels of responsibility within the department. Some of the areas where training was provided were;
The Conversion Process in Detail As described above, a hybrid conversion approach was chosen based on the results of a pilot analysis study. This approach involves a two-step process for locating features:
This sub-task includes the preparing the existing paper documents for use in the field. This pre-conversion task involves the collection of the appropriate intersection drawing (25’ scale drawings) copies for an entire delivery area. The intersection drawings are then separated based on quad and grid (2000’ X 2000’ area). A copy of the planimetric map (400’ scale) per grid is also contained in each packet. Any appurtenances needing to be metro-teched (located using a metal detector) and GPS located are scrubbed or marked on these source map copies. Field Validation The activities of the Field Validation sub-task consist of performing a windshield survey of the water and sewer system assuring that the information in the Data Packets accurately reflects what is actually in the field. Field validation crews are responsible for marking the discrepancies on the source maps and logging discrepancies which must be resolved by further research. The markings by these crews must be legible because the three subsequent steps of Metro-teching, GPS, and conversion are to interpret the markings. Also, for the future resolution of the discrepancy, proper logging and tracking must be performed. The field validation crews are painting, blue for water and green for sewer, on the above ground features that are marked on the drawings to be GPS collected. Metro-teching The “Metro-teching” sub-task involves locating using metal detectors and marking in the field, significant line jogs, main line valves, paved-over manholes, and any other underground features scrubbed in the Data Packets. The device is used to detect the underground facilities. Any discrepancies located in the field are logged and marked on the source. Markings on the sources must be readable for the two subsequent steps of GPS and conversion. Also, proper logging will expedite the tracking and resolution of discrepancies. GPS Collection All appurtenances scrubbed (marked) in the Data Packets are geographically located by their x,y-coordinates using the GPS equipment. The GPS crews ride on mountain bikes from point to point. The GPS beacon is located above the rear wheel and the data logger is on the handle bars. Those points, not able to be GPS located, are logged as discrepancies and delivered with the completed data. A database with all discrepancies is delivered for the City’s use. Discrepancy resolution will be instituted in the maintenance of the GIS system. GPS Quality Control GPS Quality Control validates that the GPS locations and appurtenances meet the GPS Data Collection standards. The task involves a comparison of GPS points, to the Intersection Drawings, and to a photogrammetrically compiled land base. College interns are utilized to assure quality GPS information is received by the City. Conversion The Conversion sub-task consists of using traditional conversion techniques to capture water and sewer data from dimensions on the intersection drawings referencing landbase features. The data collected during conversion is integrated with the information captured by the GPS crews to generate the final product. Conversion Quality Control The Final Quality Control activities of performing traditional manual checks assures that the GIS data meets all specifications prior to the installation on the City’s AM/FM-GIS system. These checks consist of plotting each product (25’, 100’, and 400’ scales) to validate the contents of each map. Database validation is conducted by printing the database and comparing each feature and its attributes with the source maps. Interns are utilized to assure quality final product is loaded on the City’s GIS server. Final Loading The final loading in the conversion sequence requires installing the delivered data on the City’s GIS. The graphics and attribute data, which has undergone complete quality control, are merged, incrementally, with data already on the City’s GIS server. This automated task requires the management of processing routines and the on-line verification of successful results. Lessons Learned Planning/Advanced Preparation Proper planning and advanced preparation are key to meeting schedules. Also, realistic schedules are essential for meeting them. The way to achieve these two objectives is to communicate effectively with all stakeholders in the project and rely on their input. With the number of different teams and dependent tasks involve in the generation of the City of Virginia Beach Public Utilities’ AM7FM-GIS, commitment by each team and an understanding that slippage in the schedule will affect many other task is important for each team to understand. The best way to handle this situation is to communicate effectively and involve everyone. Coordination meetings with field crews, technical staff, management staff, and executives on a regular basis also are successes of this project. Everyone was kept “on the same page” at their various levels. Also, valuable ideas and input at the coordination meeting made it easier to adhere to schedules. Each group could voice their concerns or comments and corrective actions were taken immediately before the problems became uncontrollable. Also, through the coordination meetings, the whole process was made more efficient along the way to completion. The input of each group eliminated any surprises for the subsequent tasks. The planned approach to the data conversion eliminated any duplicate work for the field crews. The plan called for an efficient collection of data. The field validation step allowed for a complete analysis of the source maps and field anomalies before the expensive equipment of the metro-teching and GPS tasks began collecting. It made for a more efficient environment for these crews. Also, the discrepancies that were marked on the source maps allowed the Metro-tech crews to determine whether to visit a structure location or not. For example, a paved over manhole would have to be visited by the Metro-tech crews to mark them for GPS to locate. If all manholes had been assumed to be exposed, then many structures would not have been GPS located or all features marked on the maps to be GPS located would have to be visited by Metro-tech crews. It was discovered that providing the field validation up front actually saved us time and money for the two other crews and also increased the “hit rate” for located features and the accuracy of the final product. Project Tracking As mentioned in The Conversion Process, each team logged any discrepancies that were encountered. These discrepancies were logged into a database so that querying and subsequent resolution of the discrepancies is made easier. If the next team in the conversion sequence could resolve the discrepancy. Without the discrepancies in a database, resolution and investigation of them would be more difficult. Maintenance System Once data is loaded into the GIS server, it must be maintained so the GIS does not immediately become out-of-date. This task involves adding new information from development and CIP areas as well as changing information as a part of the physical maintenance of the water and sewer system. Also, there is a freeze period once intersection drawings and planimetric maps are pulled for conversion until the final loading is performed. Any changes in the specific delivery area occurring during or after conversion will need to be updated. Furthermore, problems encountered during field work and conversion are logged in a discrepancy database. Preceding the final loading, investigation and resolution of these discrepancies is another responsibility in the maintenance phase of the project. Customized Maintenance Software was developed to make this task efficient. The Maintenance Software was prepared and in place before the first delivery was accepted. Also, training on the soflware was administered just before the actual updates need to be done. This allowed for updates to the system to be administered immediately after the data was loaded on the server. | |||||||||||
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