Aerial survey company Bluesky has launched an online map to assist in the assessment of the health and state of vegetation across England and Wales. The detailed Colour Infrared (CIR) map contains a wealth of information essential to support major environmental projects including crop monitoring, coastal management and forestry studies and is the perfect complement to the aerial photomaps and height models already available online. Visitors to www.bluesky-world.com can search the online map using a place name, postcode or geographical coordinate before viewing their chosen area or downloading GIS ready files.
Using the latest digital imaging technology Bluesky has captured the CIR information, which is invisible to the human eye. Specially developed sensors mounted on a survey aircraft are used to record measurements from a specific part of the electromagnetic spectrum, the scientific term for the collective types of energy and light emitted from the sun, which includes both visible (the normal rainbow of colours we see everyday), and invisible (such as near infrared) parts.
Providing a unique view of the earth’s surface CIR images provide a valuable tool for studies in landform, vegetation, pollution and other effects of human activity on the earth and our environment. For example, leaves of healthy, growing vegetation reflect a high level of near-infrared wavelengths and appear red on colour-infrared film while unhealthy or dormant vegetation may appear light red or a light shade of blue-green. These obvious colour distinctions make colour-infrared photographs useful in assessing the health and coverage of plants.
Water, on the other hand, absorbs near-infrared wavelengths and appears almost black in the image, although water with varying amounts of suspended particles appears as shades of blue. In addition, near-infrared wavelengths penetrate atmospheric haze and result in clear, crisp images even when traditional aerial photography cannot be captured.
“CIR data is simultaneously acquired during the GeoPerspectives data capture programme,” commented Rachel Tidmarsh, Managing Director of Bluesky, “making it the perfect complement to the other layers of detailed geographical information that are already available online at www.bluesky-world.com, including the most up-to-date aerial photography and detailed height models”.
GeoPerspectives is a joint venture between Bluesky and Infoterra providing national coverage of orthorectified aerial photography, digital terrain & surface models (DTM/DSM) for 3D modelling, and colour infrared imagery (CIR) for vegetation analysis.