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Fast, Accurate,
Reliable Digital Terrain Models
 LIDAR (LIght Detection And Ranging) is a fast and reliable airborne method of obtaining 3-dimensional data for the
creation of a Digital Terrain Model. With an integral digital frame camera, digital color images can supplement the lidar
data for a full evaluation of ground information. An airborne lidar is an active sensor using a laser to measure distances
to features and the ground.
Our complete lidar service is capable of producing a
DTM to an accuracy of better than +/- 15cms (6 inches), with point to point accuracies even better. The system is extremely
useful for applications where a high degree of accuracy and speed are necessary, or where accessibility is difficult. A detailed
DTM can be produced by lidar in a much shorter time frame than a similar product using any other technology. With our careful
attention to quality control and proper calibration, sufficient data can be collected to produce 0.3 meter (one foot) contours.
The lidar system can emit energy pulses at frequencies of up to 200,000 Hertz - that is 200,000 times per second.
These pulses are reflected off the ground, vegetation or man-made structures at different time intervals, allowing the distances
between emission and reception to be calculated. Using these distances, along with the attitude of the laser (from the inertial
system) and its position (from the GPS), the position and elevation of each spot can be calculated. With the high pulse emission
rates, the laser can obtain as many as 3,000,000 3-D points per minute. Depending on the flying height, the aircraft speed,
and the frequency and width of the laser scan, the ground point density can be as much as 10-40 points per square meter
As mentioned, we can supply optional digital imagery, collected separately or at the same time, which can be
digitally rectified to produce black and white or color digital orthophotos.
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