New Construction Methodologies using GIS, GPS, and the Web

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New Construction Methodologies using GIS, GPS, and the Web

Ed Wiegele
VP Pipeline Division
M.J. Harden Associates, Inc.
1019 Admiral Blvd.
Kansas City, MO 64106

Abstract
M.J. Harden’s approach to new pipeline construction has evolved from the successful completion of thousands of miles of electric transmission, fiber optic, and pipeline projects. The basic method-ology has been successful for over 20 years. The general approach is to establish an accurate control network that will be used throughout the project. All the base mapping, environmental surveys, right-of-way, and other third party surveys will tie to the same control network.

Contructing a pipeline
When a pipeline company is faced with a new construction project, most companies take a rather traditional approach. In many cases, the marketing or planning department identifies the general beginning and ending point of the proposed line. Before long, rough lines depicting possible routes are drawn on regional or national maps. Engineers are brought in, the routes are refined and drawn on more detailed maps. Soon, other departments begin the various route refinements, including environmental assessments, land acquisition, flow modeling, field surveys, etc. It is at this point in time that most projects begin developing multiple process paths, which could cause divergence.

Each group, in working with their own source documents, data collection procedures, and schedules, may create independent “islands of information.”

Many pipelines are electing to take an alternate approach to the traditional approach. This is driven primarily by the dramatic changes in technology over the last 5 years. Reference methods are moving from chain and transit to GPS, CAD is integrated with GIS, and many of the drawing requirements can be accomplished automatically. Additionally, extensive environmental and construction requirements make the traditional approach difficult to accomplish in the shortened time frames allowed. Strong project management and coordinated team approach (Environmental, design, ROW, survey, permits, etc.) are critical to ensure a successful project. To do this, companies must start with solid base mapping to make sure that all survey information and location information was accurate and can be immediately viewed and adjusted.

The general approach to current projects is to build an accurate base for mapping and field surveys that is used throughout the pre-construction field activities, design, construction and as-builting of a new pipeline. This reduces the amount of field surveys required from alignment adjustments since those measurements can be made on the map or through photogrammetric measurements. As data was collected, databases are built for use and modification throughout the project. When the project is completed, a database is delivered that can be maintained and supplemented with operational data. The following describes the basis of this approach. A more detailed explanation is contained in Attachment A.

Build an accurate, continuous land base using photogrammetric mapping techniques and GPS surveys to orient the proposed pipeline to the real world and provide accurate field verification points. All field surveys tied into the land base, which is based on the same control established for mapping.
Fully-controlled by GPS surveys and analytical triangulation, aerial photography is exposed at an altitude compatible with the final scale of sheets to be produced. This provided the capability of accurately refining the centerline alignment and served as a background for other data to be collected and submitted to permitting agencies.
MJH uses the controlled flights and analytical triangulation to create fully ortho-corrected photo image worksheets with a project coordinate grid. These worksheets are used as a base during the pre-construction field activities, pipeline design, and for creation of the final alignment sheets.
Prints of the ortho worksheets are used to facilitate additional surveys, wetland studies, environmental studies, centerline staking, etc., as a common accurate base. Data compiled on the worksheets can be returned for update of the continuous land base file and facility model.
Once the alignment was refined, a profile can be extracted from the Digital Terrain Model (DTM) and used for hydrostatic test profiles, flow studies, permit drawings, perform DOT class analysis, depict pipe requirements, trench plug/interceptor dikes, etc.
Permit drawings, land plats, erosion and sedimentation drawings, etc., are isolated from the continuous file and supplemented with appropriate data.
Other supplemental mapping requirements, such as special sheets for access roads and pipe storage yards, were easily produced out of the same centerline and land base file.
Adjustments to the alignment are noted during the survey and updated in the digital files. All survey information is forwarded from the field to MJH via the Internet, thereby providing instant review of the survey points and sometimes-same day verification of the data. Note: as alignment adjustments are made, the continuous centerline file is updated by moving and/or adding/ deleting PIs and the centerline geometry was re-calculated. MJH creates Web sites for the review of alignment sheets electronically by project personnel, which reduced the need to express mail hard copy sheets. This site also provided schedule updates, right of way status, environmental drawings, data for reporting to environmental agencies, e-mail capabilities and a message boards.
All of the preliminary survey and alignments for the FERC filing process are produced using coordinate values for the centerline and related features which are fed into M.J. Harden’s PipeView and SheetGen software. This allows for the immediate generation of alignment sheets from project data collected in the field, significantly reducing turn around times.
When the pipeline is constructed, the as-built survey is tied into the straddle points previously established. The survey is then used to adjust the continuous centerline built in the design phase and supplemented with the facility data, such as materials, crossings, etc. Horizontal, and slope-chain stationing can be maintained for all features.
All data is loaded into a central database. Construction alignment sheets are generated from the continuous land base and facility model. Graphic features are generated onto the center-line based on the features’ station values or X Y location. This has proved to be a much more efficient way to produce alignment sheets than traditional CAD methods. This methodology provides cost savings and the ability to accommodate multiple scope changes on a project.
Final delivery is a graphic and attribute database that can be maintained as future operations proceed. This database can also be used for reporting and analysis. Delivery can be directly loaded into a GIS, eliminating the cost to convert alignment sheets and other data collected in a manual process.
Automatic Alignment Sheet Generation
One of the most exciting areas of pipeline application development is the capability of generating a pipeline alignment sheet directly from a continuous database model (such as a GIS). An automatically created alignment sheet is now simply a report that can be made on request.

Using specialized alignment sheet generation software, sheets are generated within minutes. The land base and facilities graphics are clipped from the digital model and the various "bands" of data are generated from the attribute and field note database. The "pipe centerline band" can be created with just a planimetric (vector) land base, a scanned aerial photo background (raster), or a combination of these. It can be generated for any section of the pipeline or for a predefined map sheet area. Once changes are made to the digital model, a new sheet can be generated, and the old sheet can be discarded.

By using this process, the work required to digitize traditional CADD-type as-built alignment sheets is drastically reduced. Furthermore, as changes to these sheets are needed, most of the update work can be accomplished directly through the database. The end result is a practical, accurate, and flexible solution without the high creation and maintenance cost of typical CADD files.