Light Detection and Ranging (LiDAR) technology has become a valuable tool for measuring and recording elevation data for use in topographic mapping and three dimensional terrain/surface modeling. LiDAR offers advantages in both data acquisition and processing as compared to traditional photogrammetric elevation data gathering methods.

There are a wide range of uses for LiDAR technology. The elevation data provided by LiDAR is a perfect complement to our high-resolution imagery, as it adds vertical dimension to enable 3-D modeling and much more.

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Advanced LiDAR Sensor Technology

MJ Harden operates the latest technology in LiDAR systems, the Optech Airborne Laser Terrain Mapper (ALTM) Gemini. LiDAR is an active remote sensing system that records hyper-accurate horizontal position and vertical elevation values of precise points on the ground. LiDAR data are used to produce highly detailed digital elevation or terrain models. This is especially important in the pipeline, oil and gas, mining, urban planning, disaster management, and utility and telecommunications industries.

MJ Harden's LiDAR system in mounted in one of its aircraft and is fully integrated with an airborne global positioning system (GPS) and inertial measurement unit (IMU). The Gemini's system’s configuration can be varied to fit a wide variety of projects. The system has variable pulse rates, swath widths and scan rates which allow the sensor to adapt to varying topography, land cover, and project size and shape.

The increased pulse rate of the Gemini (167 kHz) greatly improves the efficiency of the ALTM by providing greater geographic area coverage while maintaining high point density. One of the many benefits of the Gemini multipulse technology is that it acquires maximum point density while flying at higher altitudes. This reduces acquisition costs by minimizing collection time in the air. Few other sensors on the market are able to compete with Gemini's performance. This allows MJ Harden to increase efficiency and continue to meet current and future demand for high-quality geospatial services to our clients.

Superior LiDAR Processing

MJ Harden's approach for processing LiDAR data is based on years of experience in the mapping industry. It is our experience that a single software algorithm cannot accurately filter LiDAR elevation data. The LiDAR filters have to take into consideration the differences in land cover (vegetation) and topology contained within the project area. Filtering techniques that make the most of smoothing algorithms, in the end do not accurately represent the true surface topology. This process will yield an interpolated ground surface rather than the actual bare earth surface. This can be seen in heavily vegetated areas as well as highly urbanized locations. The currently available processing software is vastly improving but still needs human intervention with respect to LiDAR processing.

Raw LiDAR data sets contain extremely large data files. The fundamental challenge with each project is to accurately identify the non-earth features and classify them in the data set without changing the surface features and the corresponding surface accuracy.