PE&RS November 2001

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Lidar: Transitioning Technologies from Lab to
Applications Around the Globe

The ability to collect and process large volumes of elevation data holds great interest to those who need highly accurate information in making critical decisions when time is of the essence. Technological advances in terrain mapping developed by NASA and commercialized by U.S. firms are now being utilized on a global basis. Just such a venture is resulting in export of U.S. technology and engineering experience to several points around the world.

TerraPoint LLC, in partnership with the Houston Advanced Research Center (HARC) has commercialized proprietary lidar (LIght Detection And Ranging) technology obtained from NASA. “Success in any venture hinges on your partners,” said Dr. Jack Hill of HARC in Houston, Texas, and on staff at Texas A&M University. “Picking the right partner can insure the probability of your success. We chose Transamerica Corporation because of the stability and financial resources of their Real Estate Information Group.” The discussions to form TerraPoint were initiated by Hill in 1997 and took form when Dan Cotter joined the company from the TA Flood Hazard Group to start TerraPoint. “We have been fortunate in picking the right partners outside the U.S.,” said Cotter, company president. “Having in-country knowledge and contacts is essential for timely and effective execution of these large, far-flung projects.”

Flying High in the Alps
A case in point is the Swiss Department of Agriculture who engaged SwissPhoto, Zurich, Switzerland and TerraPoint LLC, Houston, Texas to develop highly accurate elevation and surface terrain models for over 20,000 sq. km of Swiss countryside with the specific application of defining forest boundaries now encroaching on agricultural land. According to Erich Keller, project coordinator, lidar was the chosen technology not just because of the ability to rapidly collect data, but the regularly spaced grid produces a high density of elevation points which more clearly define the interplay between crop and forest boundaries. “Precision is important and while we were aiming for 50 cm vertical accuracy and 1 meter horizontal accuracy, TerraPoint has consistently provided datasets that are at or better than 30 cm “z” and 60cm “x & y” RMSE which are well under specifications, and have exceeded our expectations,” said Keller.

Working jointly, SwissPhoto and TerraPoint have developed data processing algorithms to filter terrain data for feature identification. These proprietary processes automatically remove, or may extract specific features and are supported by manual editing and Quality Control to enhance the dataset accuracy. Likewise, the aerial collection is a joint effort; SwissPhoto flies a Pilatus-PC6 single engine, fixed wing aircraft with the TerraPoint lidar unit installed in the fixed winged aircraft and accompanied by a technician. Following collection, the data is sent overnight to Houston, Texas where Swiss technicians work closely with the U.S. staff to calibrate and filter the data. “We are very pleased with SwissPhoto’s ability to maneuver in the difficult terrain. They handle all flight planning and collection and will be delivering the surface models to the Swiss government along with orthophotos, which are being ortho-rectified to the lidar data. “It’s the combination of Swiss precision and American technology that are producing these results,” said Cotter.

Since the project includes all agricultural areas up to 2,000 m above sea level, much of the terrain is rugged and includes dramatic re-lief. The collection units operate at 900 m above ground level, flying at 140 knots per hour. “It is the combination of speed and elevation that gives us the high density of points for the exacting feature extraction we need for this client,” said Thomas Wüthrich, CEO of SwissPhoto. “We believe this technology has wide ranging applications in Europe, the Middle East, and Northern Africa where the two firms have a long term strategic alliance. Our joint efforts of collecting and processing data with the vast technical experience of both firms has made the parts much greater the whole.”

“The project has not be without difficulty,” said Jürg Lüthy, project manager for SwissPhoto. “We can start with uncooperative weather during the fall of 2000 and continuing through the winter of 2001. One of the contract deliverables is to provide feature attributes or classification for our government buyer. We now have in place an automated process which will identify and classify specific features and we are pleased with the results.”

According to David Nale, president, SwissPhoto Group U.S., “We believe this to be the first of many such projects combining aerial imagery with lidar-generated terrain data. The ability to create highly accurate feature extraction from the dense dataset expands our capabilities in congested urban settings, difficult and inaccessible territories, or remote countries. We feel that assistance to developing countries with detailed mapping needs for infrastructure, or mapping urban canyons in Europe’s congested cites holds great promise. These combinations of evolving technology and professional know-how are redefining the mapping landscape.”

Working jointly, the two firms have developed an automated feature extraction process to classify forestry, croplands, and specific structures which are being classified and attributed by categories then labeled for identification. The Swiss Department of Agriculture will use the extracted data features for land management and change detection. Prior to creation of the terrain models, these functions were handled manually and were time consuming and costly. With the combination of digital-orthos and feature extracted surface terrain models, the manual edits and field visits are greatly reduced. Additionally, lidar collection can proceed night and day, unlike orthophotography, and is not dependent on sun angle, which greatly reduced the collection period. With introduction of the automated feature identification, the integrated spatial and text database will be completed in a fraction of the time required by more traditional methods. But one size does not fit all and it is here where the professional experience comes to bear.

Flying Low in the Jungles of Malaysia
“ Each project has its own unique problems!” said Tony Tubman, PE, director of Operations for TerraPoint. Based in Calgary, Alberta, Tubman heads the scheduling and deployment of four fixed wing lidar units around the globe. “Flying in the jungles of Malaysia has a totally different set of challenges when compared to Switzerland or Japan. Atmospheric conditions are dramatically different and moisture content, temperature, and pollution can, and do, affect the data collections in addition to the logistics of flight planning. Let’s take pollution;” said Tubman, “pollutants stratify at different levels in Japan than in Houston and each can create different anomalies in the datasets. The ability to detect these unique anomalies before the data is sent to processing is critical. We have ground-level QC processing at the end of each mission and we make an immediate decision on the validity of the data, determine if we need to re-fly, recalibrate, or add ground control before it is shipped to our processing lab in Houston.”

Recently, TerraPoint completed a major project in Malaysia working in conjunction with MinConsult, a Malaysian professional engineering firm, and Ground Data Solutions. The project is divided into two sections of corridor mapping for a 680 km electrified tilting train project involving reconstruction of an existing line which will extend from Singapore in the South, to the Thai border in the North. “This is the first planning phase of the project,” said Dr. Dennis Ganendra, principle and director of Engineering for MinConsult located in Kuala Lumpur. “We are building a twin line for the high speed passenger trains and will also upgrade and straighten the exiting line, although the exact type of train has not been determined. The lidar technology allowed us to collect a very dense surface terrain model so that we have exacting details of the rail lines.” The corridor terrain model was completed using both fixed and rotary wing mounted units. The dataset has gridded data points at 1.3 m spacing. The Nomad aircraft used to collect the data was provided and operated by the Malaysian government and flew the corridor at 2,500 ft. agl. Ground Data Solutions is delivering the DEM and Laser Shadow Mosaic including 1 m contour maps to the Railway Authority, according to Hj. Wan Ibnul, general manager.

In addition to the railway corridor, TerraPoint is working in conjunction with MinConsult to collect over 1,000 km of terrain and surface data in Kuala Lumpur to include the “high tech” corridor connecting their business district with their new airport. “We believe the availability of such an accurate and detailed terrain model will enhance our ability to assist in urban planning and future transportation projects, and will assist in attracting new industries to the area,” concluded Ganendra.

The logistics of planning and executing projects with such vast global reach require tested experience. “In order to compete our Malaysian Project on time,” explained Steve James, vice president of International Sales at TerraPoint, “we had to re-deploy one of our units operating in Japan, and crate and ship it to the Malay Peninsula. It is not a simple matter of over-nighting these instruments like the data;” said James, “you have re-export registration with the U.S. State Department in addition to Customs for each country, plus the logistics of flight planning and execution.”

Japan to Central Africa
TerraPoint just completed a 25,000 sq. km terrain model collection in Japan through a partnership with Mitsubishi Corporation and Japan Space Imaging. The terrain models will be used primarily for ortho-rectifying satellite imagery, but the partnership intends to make other uses of the datasets to include 3-D visualized models for other products such as in-vehicle navigation systems, which are developing rapidly in Japan and Western Europe. James served as project manager for the multi-year collection and works closely with the Asian alliance.

“But flying in Japan is easy compared to one of our next projects,” said James. “We are proposing to collect digital elevations models (DEMs) for establishing a geoid network in a Central African nation where no known reference points exist. We have no survey points and everything must start from scratch! It is not just the equatorial climate; the political climate is equally warm. We have a new set of challenges not faced before, in addition to the punishing weather conditions,” James concluded. The project is awaiting an end to the rainy season.

Darkest Connecticut
“ Not unlike the challenges we faced in deepest central Connecticut,” quipped Cotter when asked to comment on the difficulty of working abroad as compared to the U.S. His reference is to a large area lidar collection in conjunction with AERO-METRIC, INC. of Sheybogan, Wisconsin, a major U.S. photogrammetric firm. This specific project was initiated by multiple state agencies for environmental, planning, and transportation purposes, among others. The geographic dataset covers the entire state and will be used to create “bare earth” models with features removed and terrain models will be available for feature extraction such as 3-D structure graphics.

 “We were able to minimize our lost time due to inclement weather in an already narrow window of collection time for imagery and lidar in the state,” Said Pat Olson, senior vice president. AERO-METRIC is using TerraPoint’s DEM to finalize processing of 5,000 sq. miles of ortho-rectified imagery beginning this fall. “This is one of the largest lidar-photogrammetry projects in the U.S.,’’ said Olson. “We will begin making available the imagery and related products derived from lidar to which we will add other features as required by our clients. Lidar gives us the capability to expand our products and service. It shortens our processing time, allowing night and day collection for DEM creation during the critical ‘leaf off’ flying season. We are just beginning to explore its many applications and uses,” Olson concluded.

 “Each of these projects holds unique challenges,” said Cotter, “but the application of lidar technology has greatly reduced the time to collect and the cost of processing surface models for each specific application. In some cases, it was the savings in time that made the project feasible,” Cotter concluded. “We are continually looking for projects and partners where we can expand our capabilities in applying technologies to specific challenges.”

Ronald L. Plaster is managing director at TerraPoint LLC. He serves as director of Sales and Marketing for the US. Prior to joining TerraPoint, he worked for Factory Mutual Engineering where he specialized in hazards analysis and risk management and for Marsh McLennan Companies placing coverage for political and financial risk. He holds an MBA from Abilene Christian University.

214-571-1602 office
214-571-1650 fax
www.TerraPoint.com

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