LiDAR in Houston, from p. 35
ALTA/ACSM Land Title Survey corner by Gary Kent
Q: A:
I have heard rumors of a new version of the Standards for ALTA/ACSM Land Title Surveys. Is there a new version and when will the new standards be effective?
The NSPS Committee on ALTA/ACSM Standards, with input from attorneys on the American Land Title Association’s committee and about 100 interested surveyors, has been working on a new version of the standards for the last year and a half. The document, titled the 2011 Minimum Standard Detail Requirements for ALTA/ACSM Land Title Surveys, is nearing a final draft. Later this summer there will be a joint meeting of members of the NSPS and ALTA committees to review the entire draft and finalize any outstanding issues. The consensus version will then be voted upon by the entire membership of the American Land Title Association at its annual meeting in San Diego in October, and by the NSPS Board of Governors and Board of Directors at its fall meetings in Orlando in November. It is anticipated that the new standards will go into effect on February 1, 2011. The document will be available on-line and in various publications prior to its effective date. A future column will provide more details on the new version, but in addition to a number of changes and revisions, the 2011 ALTA standards will represent a major rewrite of the current standards, with various parts completely reorganized.
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ACSM BULLETIN june 2010
It wasn’t long before others at the University of Florida warmed up to LiDAR. This was inevitable, especially after the two scientists developed techniques to remove and minimize some of the errors seen in the early years and the equipment was fine-tuned to collect large quantities of data. As many as 167,000 points per second can now be mapped with LiDAR compared to the 3,000 when the technology was in its infancy. Shrestha’s and Carter’s research has changed the way the State of Florida monitors erosion on its coastline. They produced the highest resolution 3-D images in existence of the San Andreas Fault, and their LiDAR expertise has taken them across the globe to map Mayan Ruins in Belize and volcanoes in Hawaii. Evaluations made using LiDAR before and after a landfall of a hurricane or an earthquake can be used to improve such things as building design, as well as develop powerful predictive methods to better anticipate the response needed in future catastrophic events. Future NCALM research work will explore the possibility of using LiDAR to map a variety of phenomena be they glacial movements on the North Pole or the migration of penguin colonies in Antarctica. With LiDAR, the ground’s surface is “sensed” remotely using a small plane, such as the Cessna 337 Skymaster operated by NCALM, and laser pulses. Thousands of small cone-shaped pulses travel through a hole at the bottom of the plane to the ground and a unique detector picks up rays reflected from a point on the ground. Then each point’s distance is determined by measuring the time delay between the transmission of a pulse and the detection of reflected signals. The plane’s location and movement in the air are tracked by an inertial measurement unit fixed inside the laser system using a GPS receiver mounted to the plane and others stationed on the ground. Both the location of a plane and the speed of its movement are used, along with the laser data, to produce detailed 3-D topographic images of the terrain. “In coming years, our group plans to develop a next-generation LiDAR system. The unit would be less expensive than commercially available systems and allow for some of the most accurate, highest-resolution observations possible in laser mapping,” Shrestha said. “We want to develop a system like no one else has developed. This would really change what could be done with this technology. The new system would have new features, be faster, smaller, and capture more data during each flight than we can today.” According to Shrestha, this system would use a much shorter pulse-length laser, increasing the number of points that could be mapped per second to 800,000. The impact on data accuracy and the amount of time needed in the air to collect the data would be enormous.