About Lidar | How Lidar Works
Lidar Example Products I | Lidar Example Products I I Lidar Applications
Example Lidar Projects | About Aero-Metric Anchorage
How Lidar Works
Lidar is an acronym for LIght Detection And Ranging. It is a rapidly emerging technology for determining the shape of the ground surface plus natural and man-made features.
In the mid-1970s Aero-Metric pioneered the use of laser-profiling systems in Alaska, primarily for sea-ice studies. Significant technological changes have occurred in the intervening years. More recently, Aero-Metric has been a leader in implementing airborne GPS and inertial measurement units for precision flight and image management for optical and digital imaging systems.
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By merging laser ranging, GPS positioning, and inertial attitude technologies, Aero-Metric offers airborne laser mapping to directly measure the shape of the earth's surface beneath the aircraft's flight path. This elevation data is generated at the rate of thousands of points per second, with absolute vertical accuracies of 0.15 meters to 1 meter.
After hitting the tree-canopy the laser beam finds a hole between the foliage and reaches the ground. The returns are registered and a dataset is created instantly. Primary products derived from the raw Lidar data include: |
Hope, Alaska intesity image |
Intensity Image
When lidar data is collected, the instrument also measures the intensity of the returned light. It creates an orthorectified image that is comparable with a coarse photograph. Colors can be assigned to the elevation levels. |
Digital Elevation Models
When lidar data is collected using four returns, DEMs may be classified various ways depending on client interests. The most common classification is bare-earth; another is vegetation. Because there may be more than one return in vegetation which allow a look at the undergrowth, data may be classified as first, second, third or fourth returns, and bare-earth. Many above-ground features may be classified separately. Most often used are the first and last returns. The first will show the highest features such as the tree canopy, buildings etc. The last return is ground level. This data set will provide valuable accurate data on the surface of the earth. |
Fog Creek, Alaska , Bare-Earth DEM
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Fog Creek, Alaska, First-Return DEM
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TIN: Triangular Irregular Network
From the collected points a TIN is built. The more data included in the process, the more detailed this model will be.
3-D Models
When overlaid with aerial photography, a detailed representation of the area in natural colors can be created. The model can be rotated and viewed from all angles, lit in a multitude of ways, edited to virtually implement designs and calculate and illustrate the results and consequences of engineering projects. |
T.I.N., Anchorage Waste Facility, Alaska
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When overlaid with aerial photography, a detailed representation of the area in natural colors can be created. The model can be rotated and viewed from all angles, lit in a multitude of ways, edited to virtually implement designs and calculate and illustratethe results and consequences of engineering projects.
3-D natural color model, Portage, Alaska
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