New Construction Methodologies using GIS, GPS, and the Web

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.

The Benefits
The benefit of this approach is the ability to build an accurate model of the real world and place the pipeline into that model. As adjustments are made, ties to physical features may be measured using photogrammetric techniques rather than re-surveying the same feature as it relates to the centerline. The continuous databases built throughout the project are delivered in a GIS format, eliminating the cost to convert manual records when a GIS is implemented. The following describes further benefits:

The initial photo mission is flown, controlled by GPS survey, and the images are ortho corrected. Ortho corrected imagery is compiled by a digital process that corrects the image to horizontal scale. This means that all of the compiled digital data is shown on the photo image at correct scale and in its proper position. Digital data remains intact to scale for future plotting. It is not altered to fit a rectified image or digital drawing of imperfect scale. Using only rectified imagery, each route adjustment and each additional feature displayed on the photo would have to be manually adjusted to fit the photo image, taking additional time.
This same ortho is used for FERC filings, construction alignment sheets, site-specific drawings, ROW plats, permit drawings, route refinement, environmental permits, and as a base for a future AM/FM-GIS.
The centerline is refined using this methodology with limited access to private property. The engineers also have access to technology, capabilities, and additional data not available from viewing hard copy map sheets.
As-built surveys in the field are expedited, since the physical features around the pipeline have already been mapped. Only the centerline needs to be modified and new attributes added. The final alignment sheets are generated from the continuous file using software, rather than drafting all new sheets in CAD. The attribute data is also available for other applications and queries.
Both graphic and a facility databases are included in the final delivery. Hardcopy alignment sheets will also be delivered. These databases can be loaded directly into a GIS, eliminating the cost to convert data into a GIS.
This methodology has been proven over the last 3 years on over 15 major pipeline construction projects.

The benefits of GIS are another topic altogether. The benefits of the technology are proven and the cost of hardware and software has been dramatically reduced. Many companies have implemented a variety of databases and GIS solutions to maintain their facilities—ROW, environmental, operational data, etc. Pipeline operators are using these systems for DOT reporting, pipeline integrity, and analysis of corrosion and smart pigging data. Moving to GIS is the next step in pipeline industry evolution, just as CAD was to manual mapping. However, the benefits of GIS are even greater now that positional references and bases maps are being created and maintained in a digital world.

Summary
To really get the full benefit of this technology and create the desired savings, you must integrate and change the field collection of data and how pipelines are engineered. On this front, Willbros Engineers has been forward in their approach to pipeline projects and automated many of their processes. M.J. Harden and Willbros have signed a Strategic Alliance to bring automation and web technologies to pipeline projects from start to finish. This has provided pipeline companies with increased access to project information through the web, reduced the project timelines for all phases of the project, and reduced project costs. With these kind of benefits, why do a project any other way?