CHANGE DETECTION MAPPING
BGC is an industry leader in using remote sensing technologies to observe, interpret, and understand the physical environment, particularly as it applies to mapping differential change.
Monitoring of slope movement has traditionally been limited to costly sporadic borehole mapping and instrumentation data, discrete surface measurements and observations, and interpolated geophysical data. With recent advancements in remote sensing data collection and analysis algorithms, we have been able to understand the mapping of slope processes with a greater degree of accuracy and confidence. BGC has experience working with airborne laser scanning, terrestrial laser scanning, satellite earth observation (imagery and radar), terrestrial radar, and photogrammetry for mapping differential slope change. We help our clients understand the movement rate of material near their assets and create an assessment of the associated potential hazards.
Airborne Laser Scanning (ALS)
Lidar is a surveying technology that measures distance by illuminating a target with a laser light and is typically used to make high-resolution maps. Airborne Laser Scanning (also airborne lidar) is a laser scanner that creates a 3D model of the landscape while attached to a plane or helicopter during flight. The technology collects data over spatially extensive regions requiring limited ground access to sites and is currently the most detailed and accurate method of creating digital elevation models.
Terrestrial Laser Scanning (TLS)
Terrestrial Laser Scanning (also terrestrial lidar) data collection requires ground access to scan setup locations but does not require onsite access to the terrain. The TLS data can be used to identify small-scale features not typically possible in ALS data and can create realistic looking 3D models in a relatively short time when compared to other technologies. Terrestrial Laser Scanning equipment can be rapidly deployed, and the data integrated into differential models within hours of collection.
Terrestrial & Aerial Photography
Photogrammetry is the science of measuring the distance between two points on a photo image. This system may be used to determine the exact position of surface points as well as the motion pathways of reference points located on a moving object.
The distance between two points can be determined by measuring their distance on a photo image, so photogrammetry may be used to determine the exact position of surface points as well as the motion pathways of reference points located on a moving object. Photogrammetry can provide excellent 3D models for various engineering geology applications. BGC has pioneered methodologies for helicopter-based photogrammetry data collection and differential change of rock slopes along transportation corridors.
Ground Based Radar
Radar interferometry methods are used to measure changes and displacements of natural and constructed slopes. Terrestrial methods can provide near-real-time measurements of slopes of concern. BGC are experts in the analysis and interpretation of data from the industry leading data providers and commonly used terrestrial hardware systems.
Satellite Earth Observation
Remote sensing tools can provide powerful data sets for change detection mapping. But determining which tool, or combination of tools, provides the best solution for a particular project requires in-depth knowledge. For example, photogrammetric analysis may be applied to one photograph, or may be combined with ALS or TLS to detect, measure, and record complex 2D and 3D motion fields.
BGC experts determine the best remote sensing technology for our clients’ application. Our experience ensures our clients make good technology decisions using state-of-the-art analytical techniques which ensure accurate results.