The Colorado Springs Utilities (CSU) Water Resources Department had a multi-million dollar problem. It needed to accurately and inexpensively create maps using high-resolution aerial photography that detailed—down to a six-inch pixel resolution—its north raw water treatment complex and two buried pipelines that stretch about 130 miles through the snowcapped Rockies.

Many of the pipelines aren’t easy to get to. Workers often had to tramp through wilderness areas in the forest to reach them. Collecting data in the mountains during the winter and summer lended several challenges, too. This was no typical jobsite.

Although the area to be worked in couldn’t be made easier, the process of the data collection could be. The solution to the problem was a three-tiered combination of ERDAS Corporation’s (Atlanta, Ga.) geographic imaging software products, which have the ability to collect, edit and create 3-D ortho-accurate maps that are easy to create. On Tier 1 was IMAGINE OrthoBASE, a revolutionary new digital photogrammetry product. Tier 2 implemented Stereo Analyst, which performs stereoscopic 3-D feature collection that easily and accurately extracts elevation information from imagery. Tier 3 contained IMAGINE VirtualGIS, a powerful, 3-D visual analysis tool that supports flight sequences and manages and assimilates multiple geographic data types in a real-time, 3-D environment.

“The great thing about these tools is that the user does not have to be an expert in photogrammetry or remote sensing. It’s a simple workflow that is also a total solution,” said Lawrie E. Jordan III, ERDAS president.

This orthophoto shows the Pine Valley McCulough Water Treatment Plants and Tesla Hydroelectric Plant owned and maintained by the Colorado Springs Utilities Water Resources Department.

Mapping the Water Plant

One phase of the water treatment map project involved collecting accurate 3-D data on the 25-megawatt Tesla hydroelectric plant, built at the mouth of the underground pipeline. The pipeline carries water collected from the Rampart Reservoir to the plant. The movement of water turns a water wheel, which turns the turbine and generator to make electricity. The water energy harnessed from the hydroelectric plant will create pollution-free energy. The Water Resources Department is planning to use the data gathered to upgrade the facility.

The CSU Water Resources Department used ERDAS software to create high-detailed maps of a water treatment plant on the north end of Colorado Springs. The data collected will be used to help with planning issues such as maintenance, future consumption needs and expansion viabilities.

Mapping the water treatment project was completed in about two weeks and cost about $3,500. Had the project been outsourced, CSU estimates it would have cost up to about $50,000. Now, with the help of ERDAS software, the CSU Water Resources Department for the first time will have a set of ortho-accurate, high resolution maps (scale of 1" = 200 ft) that detail the location of the underground pipelines, water sheds, reservoirs and hydroelectrical facilities they own and maintain, as well as associated property information.

Mountain Pipeline Distribution Project

Settled beneath layers of snow and ice on the Colorado Rockies, pipelines totalling more than 200 linear miles deliver raw water from collection sites set high atop the northern, southern and western mountain slopes to the springs and lakes below. However, knowing precisely how every inch of the pipelines coincides with private landowner easements, public roadways, fencing, lakes and streams, and housing developments is a challenge facing the Water Resources Department.

ERDAS’ geographic imaging software products will help the Water Resources Department to capture detailed data on roughly 130 miles of the 200-mile pipeline to create base maps. Combined with GPS, pipeline data and ESRI (Redlands, Calif.) GIS technology, the maps created will be used to chart details of the pipelines such as accessibility, maintenance history and schedules, and future water needs. The maps will also be used to monitor land use to ensure that developers seeking to build on the exclusive pristine perches do not do so on top of a 48-inch water main easement.

“Having this information really helps our people in the field deal with planning issues such as leaks, growth and maintenance,” said Mike White, senior GIS analyst for CSU Water Resources Department. “They have to know which landowners to contact when they need to get to the pipeline. They have to know where the easements are, where lot boundaries are and how to access the pipe.”

Prior to obtaining the ERDAS products, all base-mapping data capture (aerial photography, photogrammetry, orthophoto production, etc.) was outsourced. By using the ERDAS software and completing the work in-house, the cost of the pipeline project will be cut by 90 percent and completed several months earlier than if the project had been outsourced.

“Using ERDAS’ products significantly cut the overall cost of the project and has allowed us to control the level of quality of each mapping project depending on specific project requirements,” White said.

Based on his previous experience with outsourced base-mapping projects, White estimates the pipeline project would have cost approximately $2 million if it had not been brought in-house. Using the ERDAS products in-house, the project—including the cost of the software, equipment and labor—will total about $200,000 over the proposed one-year time frame.

The ERDAS Solution

“The ERDAS software does exactly what ERDAS said it would do and what we needed it to do,” White said.

Combining the powerful three-tiered solution, CSU was able to create and maintain its GIS using ortho-accurate information and a linear workflow.

Using IMAGINE OrthoBASE, CSU was able to automatically identify and measure tie points throughout an entire block of imagery, virtually eliminating the need to manually collect them. With this time-saving step, they can simultaneously model the geometry of multiple, overlapping photos using “block triangulation” and create highly accurate ground point determinations that surpass the accuracy of single-framed orthorectification techniques.

With Stereo Analyst, CSU can edit the DEM (Digital Elevation Model) and assign attributes to its vector data. Using raw frames of aerial photography and the aerial triangulation results from IMAGINE OrthoBASE, Stereo Analyst is able to greatly reduce the amount of steps and time associated with populating a GIS. Viewing, measuring and collecting in 3-D significantly improves the reliability and accuracy of the GIS data.

IMAGINE VirtualGIS can then take the resulting vector GIS layers, DEM, orthorectified aerial photography frames and 3-D objects to create realistic, interactive 3-D visualization of the terrain and environment.

Because the ERDAS products have met CSU’s expectations, White said they are anticipating the release of IMAGINE OrthoBASE Pro, a tool that will automatically extract elevation information from imagery—a powerful time-saving feature.

In addition to its ability to automatically extract elevation information from imagery, IMAGINE OrthoBASE Pro, to be released in the third quarter of 2001, uses sophisticated and rigorous artificial intelligence techniques to create base maps that transform imagery into highly accurate 3-D geographic data.