LiDAR drone system maps height of rainforest for the first time

Carbomap, a UK forest mapping company today announced that it has collaborated with l’Avion Jaune S.A.R.L and IRD (Institut de recherche pour le développement) in France to complete the first canopy height model of a rainforest using data from the first true UAV-ready LiDAR system (called YellowScan®), an approach which has never been applied before in the tropics.

The project, CANOPOR, coordinated by IRD was funded through the “Investissements d’Avenir” grant managed by Agence Nationale de la Recherche (Labex CEBA), focussed on the Paracou experimental forest site in French Guiana, which is managed by CIRAD (Centre de coopération internationale en recherche agronomique pour le développement).

The project as a whole has a range of different objectives linked to many aspects of forest mapping, and Carbomap was involved in the generation of the canopy height model using a very high density point cloud.

 

Canopy Height Model from Paracou Experimental Station

Canopy Height Model from Paracou Experimental Station. The transect at the bottom shows a cross-section of tree heights above the ground.

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Data for the canopy height model aspect of the project was collected by mounting the YellowScan® system on a manned helicopter. The helicopter then replicated the flight parameters of a typical UAV drone, and provided proof of concept for this approach.The UAV approach is more adapted to this type of work, in comparison to the current industry standard which uses full size airplanes for Airborne LiDAR surveys, for a number of reasons. Firstly the flight altitude of a UAV is significantly lower than that of a normal surveying aircraft, which helps to overcome problems of cloud and atmospheric interference in rainforest. UAV’s also fly at much lower speeds than normal aircraft, meaning that a much higher point density can be achieved.   The result is a highly cost-effective system that is especially appropriate for developing countries where airborne LiDAR is expensive to deploy.

To generate the canopy height model, Carbomap used their bespoke processing chain to extract the terrain level from the point cloud. The particular challenge of this project was the high density of the forest itself, which limited the ease of identifying the ground. To do this Carbomap developed an algorithm that is capable of retrieving the few points which correspond to the ground, to generate a bare earth digital terrain model (DTM). Once this was extracted the canopy height model was determined from the height of the trees above the ground.

The next stages in Carbomap’s forest mapping workflow are the extraction of other forest metrics from the data. Examples of this are the amount of aboveground biomass or Carbon stored within the forest area, and if multiple datasets over time are available, then the change in forest cover, from which changes in forest carbon, can also be measured.

This international collaboration, between the Edinburgh-based Carbomap and the French organisations L’Avion Jaune S.A.R.L and IRD, demonstrates the international appeal for the further development of such forest mapping approaches.

Professor Iain Woodhouse, CEO of Carbomap said, “The exciting prospect here is that it demonstrated how a UAV LiDAR can map rainforests in 3D on the landscape scale. The UAV LiDAR approach offers a low cost alternative to sending people into the field to make measurements, yet it provides much higher detail than can be achieved with satellites”.

About Carbomap Ltd

Carbomap is an environmental survey company which spun out of the University of Edinburgh in 2013. The company takes forward over four years of world-class research within the University in the development of a Multispectral Canopy LiDAR, a revolutionary, patent-pending laser scanning instrument designed to fill a gap in airborne forest survey requirements. Carbomap has a world beating team. The scientific founders have international reputations in remote sensing methodologies, satellite radar mapping, forest structure mapping, carbon sequestration and airborne survey. www.carbomap.com

About Carbomap’s technology

Carbomap is pioneering a state-of-the-art approach to measuring and mapping the world’s forest carbon called Multi Spectral Canopy LiDAR, which is optimised to measure forest properties by combining the proven strengths of hyper spectral sensing with the 3D structural information from LiDAR. Carbomap can provide forest managers, carbon traders and certifying authorities with independently verified, forest map products to support their strategic decision making. Carbon investors always need to carry out due diligence and ensure quality control to minimise the investment risk. Carbomap provides cost-effective and accurate forest information to support effective decision making.

Carbomap’s approach, which uses four wavelengths, offers significant advantages over existing commercially available single wavelength LiDAR systems. In addition to generating 3D maps as standard, Carbomap’s proprietary system utilises four specific colour bands (rather than one) that are uniquely tuned to measure the health and function of trees, thus providing information from throughout the forest, including the under-canopy vegetation, which is important for the management of fire and invasive species such as rhododendron.

“This kind of information will provide improved capacity to conduct forest inventory and to comply with the increasingly demanding policy directives intended to promote sustainable forestry, increase carbon stocks and conserve biodiversity,” said Prof. Woodhouse. “Our technology provides a cost reduction of at least 50% over traditional ground survey and also provides a level of forest information that cannot be achieved with other airborne scanning systems.”

Standard single-wavelength LiDAR systems use one colour and typically record multiple echoes: one for the top of the tree, the other for the ground surface. This is mostly used for typical surveying activities, such as making OS-type maps, or for engineering, construction and infrastructure planning.

About L’Avion Jaune S.A.R.L

Founded 2005 by three associates, L’Avion Jaune S.A.R.L started as a development and service company based on UAV technology. Reality and opportunities made it evolve to a full aerial imagery service company using manned planes and helicopters as well as UAVs. Since the beginning, its commitment to fulfills high resolution and high quality radiometric requirements has fueled its research and development department.

About L’Avion Jaune’s technology

L’Avion Jaune has created YellowScan®, an all-in-one ultra-light laser scanner intended for UAVs and other ultra-light aircrafts. With less than 2 kg, YellowScan® incorporates a laser scanner head, an inertial measurement unit and a high-grade GPS. YellowScan® has low power consumption (20 Watt) and extremely compact dimensions (20 x 15 x 15 cm). YellowScan® is the world’s lightest standalone surveying solution for drones and other ultralight aircrafts.

YellowScan® is suited for very high resolution surveys. It can operates up to 150 m above ground level with a resolution of 10 cm. Typical scan angle measurement is ±50°.

The system provides up to 3 echoes per shot, allowing to get topographic information under vegetation cover.

About l’Institut de Recherche pour le Développement

The IRD is a French research organisation, original and unique on the European development research scene. Emphasizing interdisciplinarity, the IRD has focused its research for over 65 years on the relationship between man and its environment, in Africa, Mediterranean, Latin America, Asia and the French tropical overseas territories. Its research, training and innovation activities are intended to contribute to the social, economic and cultural development of southern countries.

About the CEBA

The Center for the study of Biodiversity in Amazonia (CEBA) is a network of 11 internationally -recognized French research laboratories involved in biodiversity research in Amazonia in different aspects: biodiscovery, ecology, genetics, modelling, biodiversity & public health, social sciences, etc.

The teams of the CEBA, based in French Guiana, mainland France and the French Antilles, bring together a staff of around 150 people in total (researchers, engineers, PhD students, etc.). The CEBA fosters cutting-edge research on biodiversity in French Guiana and enables the partner teams to lead joint projects thanks to long-term funding.

The CEBA was labelled « Laboratoire d’Excellence » in 2011 in the framework of the calls of proposals launched by the French National Research Agency (ANR) in the Investissements d’Avenir programme. It will conduct its activities from 2011 until 2019.

Contact information

Prof Iain Woodhouse, Carbomap Ltd., info@www.carbomap.com, +44 7887 551724

Dr. Tristan Allouis, L’Avion Jaune S.A.R.L., yellowscan@lavionjaune.fr

More information

Carbomap Ltd. : http://www.carbomap.com/

l’Avion Jaune S.A.R.L : http://yellowscan.lavionjaune.com/

IRD : http://en.ird.fr/

CEBA : http://www.labex-ceba.fr/en

CIRAD : http://www.cirad.fr/en

Paracou_CHM_strip

The full transect with Google Earth imagery in the background.

CHM_closeUp

With the ground elevation normalised to a flat surface, this image just shows one slice of the canopy structure. Individual tree crowns are visible, and emergent trees can be clearly seen on the right hand side.

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