A New Generation of Land Base Information
By Ron Elsis, Space Imaging EOSAT
As the utility industry approaches the 21st century, providers of electric, gas, telecommunications, water and other vital services continue searching for ways to remain competitive by providing their services more efficiently and cost effectively. New emerging forms of information technology are playing an increasingly important role in the way progressive utility companies do business. One of the newest forms of information technology that is having a major positive impact on the utility industry is the use of high-resolution space imagery to create digital ortho-images–the core of today`s advanced digital land base mapping. The utility industry is potentially one of the largest and fastest growing markets for the application of high-resolution earth information in digital land base mapping. By early 1998, imagery derived from satellites with resolutions never before commercially available will be accessible within days or even hours of being collected and will be used in the creation and maintenance of highly accurate digital land base maps. When combined with high-resolution aerial photography and other lower-resolution space imagery currently available, utility companies will have a valuable information resource useful in everything from planning, implementing and maintaining facilities and infrastructure to supporting disaster management efforts and providing exceptional customer service. Ultimately, utilities will be able to access a comprehensive, globally distributed digital archive of space and aerial earth information that will allow them to become more efficient in their operations and provide services more cost effectively than ever before.
Developing an Accurate Digital Land Base
A digital land base serves as the basis for locating the position of a utility`s facilities and infrastructure throughout its service network. Since the vast majority of information needed for utilities to operate effectively is “location” related, and since precise location is determined by the quality of the land base, it is critical that utilities develop and maintain the highest quality, highest accuracy and most up-to-date land bases possible. Until recently, most conventional vector land bases used by utilities were manually developed and maintained. As a consequence, mapping and facilities information databases were often out-of-date and out-of-sync compared to actual changes that had occurred in the field. In many cases, the update backlog was anywhere from six months to a year. This inability to maintain the land base plagued the industry until the advent of digital land base mapping methods. Utilities recognized the need to create and maintain an accurate land base more efficiently and cost effectively to remain competitive and provide a high level of service to their customers. The computer-based, digital land and facilities databases of the future will enable utility users to keep their land bases much more current and accurate at a considerably lower cost than previously possible.
Advantages of Space Imagery
The use of space imagery in the development of a digital land base has clear advantages in many utility-related applications. To have practical value, a utility`s land base must be accurate, interpretable, current, consistent and affordable. These factors are characteristic of land bases derived from digital ortho-images and set them apart from those supported by traditional vector-based maps. With digital ortho-imagery, the relationships among land features are presented in their natural state without being skewed by flaws caused by data conversions and interpretation. There is none of the human interpretation or bias often present in the development of a vector land base, hence higher accuracies are possible with a digital ortho-image land base. Conventional mapping methods based on photogrammetry can often cost up to $1,000 per square mile. An ortho-image created using traditional mapping methods with 1 m resolution and 2 m accuracy can cost up to $300 per square mile. By comparison, high-resolution, high-accuracy satellite-derived imagery can cost $150 to $250 per square mile.
Some applications, however, require the higher resolution and accuracy offered by vendors of aerial mapping products. With recent high-quality satellite and aerial imagery becoming available in this globally distributed digital archive, users can take advantage of off-the-shelf pricing instead of paying the higher costs typically associated with custom data collection. Geographic information loses its value with age because many areas are under constant development, especially in suburban areas. An outdated land base can have significant negative impacts on a utility company`s ability to plan, build and maintain its field facilities and infrastructure. Current space imagery of a specific geographic area can be collected, processed and delivered to a user within days or weeks of image collection. If the required imagery is already available in the archive, it may only be a matter of hours before it`s in the hands of the user. By comparison, it can typically take anywhere from four to six months to collect and implement a typical aerial-based survey. By that time, some of the information intended to update the utility`s land base may already be outdated.
The compatibility of raster-based space imagery with vector GIS environments has long been a challenge for users of GIS and AM/FM. During the past few years, all major GIS software vendors have integrated raster data handling capabilities into their systems. Today`s space imagery products will be provided to users in a GIS-compatible format and registered to the coordinate systems specified by the user. Ortho-images and image-derived products will be delivered in standard formats that are fully compatible with most GISs.
Utility Applications for Space-based Imagery
Utility lines, pipes and other infrastructure components installed in either public or private rights-of-way are subject to interference from vegetation overgrowth that has the potential to disrupt service if regular trimming maintenance is not conducted. Major power outages in the western United States during mid-1996 were caused by power lines coming into contact with trees, disrupting service to several million customers. High-resolution space imagery will enable utilities to quickly evaluate tree trimming maintenance requirements and dispatch crews to potential problem spots so service disruptions can be avoided. In corridor planning applications, utility companies will be able to use high-resolution space imagery to plan the most efficient and cost-effective routes and locations for an infrastructure in a particular area. For example, cellular telecommunications companies planning optimum locations for their cell sites can use 3-D space imagery to evaluate the terrain elevations and land cover within an area, both of which can significantly impact the performance of their systems. Space imagery allows utility companies to conduct “what if” studies in the office without spending unnecessary and costly time in the field. The information derived from this imagery allows plans to be altered as frequently as necessary without the need for frequent and expensive field surveying. Reduced site visits and enhanced in-house planning capabilities can result in significant cost savings to utility companies.
A potentially valuable use of high-resolution space imagery by utilities is in disaster management. Floods, earthquakes, fires, hurricanes and other wide-spread natural disasters often take a heavy toll on a utility`s infrastructure. If a utility has an accurate land base prior to a disaster and can compare it to satellite imagery of the same area immediately after the disaster, it will be able to identify trouble spots more efficiently and quickly and dispatch repair crews to those priority locations. This will allow the utility to get service back online faster and reduce costs by more efficiently dispersing its repair crews and other resources where they are most needed.
By using a more accurate land base derived from space imagery, utilities also can improve their facilities` mapping capabilities by more accurately placing the locations of their facilities throughout their service network. Rapid collection, processing and delivery of imagery allows for a myriad of digital ortho-derived applications that can result in time savings, reduced costs and better services. A variety of utilities, from gas and electric companies to water departments and telephone service providers, have great expectations for the use of satellite-derived imagery to help them more efficiently plan, implement and maintain their service systems. Here are some brief comments by two potential users of this new information technology:
“There is a significant market for space imagery in the water resources field,” said Robert Weir, Denver Water Department deputy director of operations and maintenance. “The ability to overlay high-resolution satellite images on the vector maps of a GIS will be a tremendous asset in projecting run-off yields.” Donna Lindquist, Pacific Gas & Electric Co. senior research scientist, added, “State-of-the-art information technologies like high-resolution space imagery have the potential to enable utility companies to operate more efficiently, reduce operational and maintenance costs and remain competitive by providing enhanced customer services.” The use of high-resolution, high-accuracy space imagery for digital land base mapping and related applications will continue to become more widespread in the utility industry as the benefits of this revolutionary new information technology become more widely visible and documented.
If you would like to see more articles on this topic, circle R.S. 113.
For more information on this article, circle R.S. 114.
The 1 m resolution color-enhanced image of San Francisco, Calif., (bottom) illustrates the high-resolution, high-accuracy imagery that is now being offered by Space Imaging. The same images on the top left and right depict 10 m and 30 m representations of lower-resolution imagery that is available from existing satellite sources.