Geospatial analysis based on GIS integrated with LADAR
Spotlight summary: After the devastating earthquake in Haiti on January 12, 2010, disaster relief efforts were assisted by ALIRT an “Airborne LADAR Imaging Research Testbed” developed by the Lincoln Laboratory at MIT, USA. LADAR (Laser Detection And Ranging) is a method for remote sensing and measuring the surface of the earth. In LADAR imagery, a pulsed laser is used to illuminate the area of interest from an aircraft, and a sensor records the reflected light to measure the range through a time of flight record of the pulse. This range data is augmented with position and orientation data generated from the GPS (global positioning system) and an IMU (Inertial Measurement Unit), resulting in three-dimensional spatial coordinates (latitude, longitude, and height) that correspond to a particular point on the earth’s surface. A scanning mirror in the LADAR instrument continuously scans a wide area on the ground (typically thousands of kilometers) to obtain high-resolution 3D maps of the surface elevation. The LADAR data is used to generate other geographic data sets, such as digital elevation models that can be integrated with the GIS (global information system), canopy, building and contour models that have uses in many areas including assessment of roads and buildings in an emergency response area and obviously the military use.
The authors of this article present analytical tools for building classification, path finding and line-of-sight detection using LADAR data that is obtained with systems like ALIRT. Accurate measurement of object height is crucial with LADAR like methods to aid the conventional satellite imagery. In their present work, the authors have developed software tools incorporating GIS to extract features of objects like cars, buildings and trees from the LADAR data, thereby, helping to identify buildings and their locations within dense areas.
How do you accurately find your path through a rugged region on foot or in a vehicle? This paper comes up with an elaborate method to find the best path through a region. Using the LADAR data that provides the slope of a terrain and overlaying it with the GIS data, one can find the speed at which a human or an automobile would travel and thus find an optimized and fastest path. Well, for a soldier in a combat situation, the fastest path may not be the best one! The authors have devised a line-of-sight tool to distinguish between visible and obscure regions and figuring out the fastest path but hidden from the enemy. Finally, to create a virtual environment in the GIS screen with gesture control, Microsoft’s Kinect tool was adapted for user control of panning, zooming and other features as an added facility.
The authors present a suite of analytical tools to visualize and interact with LADAR data, leading to building classification, path finding, demographic and line-of-sight assessments. The Geofetch GIS tool, developed by the authors, is a useful visualization and analysis platform that can be used, for example, “to find a town, select a building within the town by applying various filters and generate a safe path to approach the building”, notably with the help of gesture based virtual environment.
The future of this work lies in the application of LADAR tools in robotic path finding and planning strategies, as suggested by the authors.
Technical Division: Information Acquisition, Processing, and Display
ToC Category: Remote Sensing
|OCIS Codes:||(100.0100) Image processing : Image processing|
|(120.0280) Instrumentation, measurement, and metrology : Remote sensing and sensors|
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