Multispectral Survey

This method uses a camera array equipped with multiple sensors to acquire data invisible to the human eye across the electromagnetic spectrum. When sub-surface features impact the overlying ground, they may be detected following a multispectral survey.

 

A series of raster transformations can be performed using GIS and interpreted in a detailed report to discuss the findings.

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For survey areas covered in vegetation, the reflectance shown by the multispectral represents the amount of chlorophyll within the plants. This is indicative of the plants’ health which may be influenced by sub-surface features.

 

For stripped or bare earth survey areas, the reflectance can represent soil organic carbon, soil moisture, or soil texture/density.

 

For example, where a feature such as a filled ditch is present, the reflectance will be different to that of the soil either side and will be represented as different colours following raster transformations. Nuances such as re-cuts and multiple fills, which would otherwise be difficult to see using RGB or with the naked eye, have the potential to be mapped.

 

RGB photogrammetry is carried out alongside multispectral to provide general mapping and identify possible earthworks. A GIS interpretive report is essential to understanding the results from a multispectral survey.