6. May 2019

Glob­al Tan­DEM-X for­est map is avail­able.

Global TanDEM-X forest map
Glob­al Tan­DEM-X for­est map
Image 1/5, Credit: © DLR. All rights reserved

Global TanDEM-X forest map

Around one third of Earth's land­mass is cov­ered by forests. DLR has cre­at­ed an ex­cep­tion­al da­ta set: the glob­al Tan­DEM-X for­est map. The map was cre­at­ed us­ing in­ter­fer­o­met­ric da­ta record­ed for the glob­al al­ti­tude mod­el of the Ger­man Tan­DEM-X satel­lite sur­vey, and al­go­rithms from the field of ar­ti­fi­cial in­tel­li­gence were de­vel­oped for glob­al da­ta pro­cess­ing. These were then op­ti­mised for dif­fer­ent for­est types on the ba­sis of tree height, den­si­ty and struc­ture. The re­sult is a map that shows the ex­tent of forest­ed ar­eas at a res­o­lu­tion of 50 me­tres.
TanDEM-X forest map – Alps
Tan­DEM-X for­est map – Alps
Image 2/5, Credit: DLR

TanDEM-X forest map – Alps

Sec­tion of the Tan­DEM-X for­est map over the Alps.
TanDEM-X forest map – southern Germany
Tan­DEM-X for­est map – south­ern Ger­many
Image 3/5, Credit: Google Earth/DLR

TanDEM-X forest map – southern Germany

Com­par­i­son of a Google Earth im­age with the Tan­DEM-X for­est map for a re­gion in south­ern Ger­many. In­di­vid­u­al rows of trees at the edges of fields can be clear­ly dis­tin­guished in the im­age, demon­strat­ing the de­gree of de­tail of­fered by the for­est map.
Dramatic deforestation in Brazil
Dra­mat­ic de­for­esta­tion in Brazil
Image 4/5, Credit: DLR

Dramatic deforestation in Brazil

The Tan­DEM-X For­est/Non-For­est Map for an ap­prox­i­mate­ly 250-kilo­me­tre by 250-kilo­me­tre area in the Brazil­ian state of Rondô­nia shows the dra­mat­ic de­vel­op­ment of de­for­esta­tion in the rain­for­est.
Comparison – deforestation in the Amazons
Com­par­i­son – de­for­esta­tion in the Ama­zons
Image 5/5, Credit: GoogleEarth/DLR

Comparison – deforestation in the Amazons

Com­par­i­son be­tween a Google Earth im­age and the Tan­DEM-X for­est map for an area in the Ama­zon rain­for­est af­fect­ed by de­for­esta­tion. For the first time, the Tan­DEM-X da­ta pro­vide a pre­cise in­sight and overview of de­for­esta­tion in the most re­mote re­gions, so that il­le­gal ac­tiv­i­ties in par­tic­u­lar can be de­tect­ed.
  • Global TanDEM-X forest map with 50-metre resolution freely available for scientific use
  • Monitoring, assessment and protection of the world’s forest resources
  • Interaction between interferometric data from the global TanDEM-X elevation model and intelligent algorithms for data processing
  • Focus: Earth observation, space, climate change, TanDEM-X, Tandem-L, Artificial Intelligence, Big Data

Forests are Earth's lungs; they help to reduce greenhouse gas concentrations in the atmosphere and thus counteract global warming, while also providing protection and resources for humans, animals and plants – and they are being lost at an alarming rate. As the view from space reveals, forests cover about one third of Earth’s landmass today. More than half of the world’s forests, which have fallen victim to deforestation since the middle of the 20th century in particular, have already been lost. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) has created a special dataset to monitor, assess, and protect the current state and development of this green organ with precision – the global TanDEM-X Forest/Non-Forest Map. Interferometric data acquired by the German TanDEM-X radar satellite mission for the creation of a global elevation model were used for this purpose; algorithms from the field of Artificial Intelligence were developed for global data processing. These have been optimised for different types of forests based on tree height, density, and structure. This has resulted in a global map that shows the extent of forested areas at a resolution of 50 metres. DLR’s global TanDEM-X Forest/Non-Forest Map is now available free of charge to scientific users.

Radar satellites can acquire image data regardless of the weather or time of day – a particular advantage when it comes to mapping tropical forests, which are usually covered by clouds. The TanDEM-X Forest/Non-Forest Map closes the gaps that previously existed in the data and, for the first time, provides a uniform overview of the rainforests in South America, Southeast Asia, and Africa. The findings are important for authorities and scientists alike, as these areas must be protected from illegal logging and preserved as important stores of carbon.

The new map can also help scientists to more precisely determine the forest biomass – a key factor when studying the global carbon cycle. The TanDEM-X Forest/Non-Forest Map thus provides an important dataset for research into global change and makes a variety of applications in agriculture, forestry, regional development, and land-use planning possible. In addition, it also allows more precise predictions to be made and appropriate measures to be taken to address the societal challenges arising from global change.

Big Data and Artificial Intelligence

The DLR Microwaves and Radar Institute has processed more than 400,000 datasets for the project. The datasets were acquired between 2011 and 2015 as part of the TanDEM-X mission. The radar experts have developed special algorithms that first evaluate each image individually and then combines them to form a global map with the goal of extracting and classifying forest-related information from the vast quantities of data. These algorithms are based on machine learning in the field of Artificial Intelligence. More information is available in an article published in the journal 'Remote Sensing of Environment' (Volume 205, February 2018). In the future, it will be possible to evaluate new satellite data and compare it with the global TanDEM-X map, for instance using time series analyses.

The developers used additional remote sensing data to validate the calculated results and differentiate forest areas from non-forested regions with a greater degree of accuracy. In particular, this includes the ‘global urban footprint’, a global map of settlements created at the DLR Earth Observation Center (EOC), as well as the mapping of water bodies by ESA’s Climate Change Initiative. The distribution of the global TanDEM-X Forest/Non-Forest Map is managed by the German Satellite Data Archive at the EOC and made available to users. The German Space Operations Center (GSOC) is responsible for the operation of the TanDEM-X radar satellite mission.

Tandem-L – forest monitoring in the future

Assessing and monitoring forest resources is a key task for current and future radar satellite missions. In particular, Tandem-L – a proposal for a highly innovative satellite mission – could in the future generate forest maps on a weekly basis and derive forest height, structure, and biomass accordingly. With its innovative imaging technology and the resulting enormous recording capacity, Tandem-L is also designed to observe other dynamic environmental processes on the Earth’s surface. The mission will set new standards in Earth observation and thus significantly contribute towards addressing global societal challenges.

  • Bernadette Jung
    Ger­man Aerospace Cen­ter (DLR)

    Cor­po­rate Com­mu­ni­ca­tions
    Telephone: +49 8153 28-2251
    Fax: +49 8153 28-1243
    Münchener Straße 20
    82234 Weßling
  • Paola Rizzoli
    Ger­man Aerospace Cen­ter (DLR)
    Mi­crowaves and Radar In­sti­tute
    Münchener Straße 20
    82234 Oberpfaffenhofen-Weßling

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