New tools are providing us with the ability to get a global picture of humanity’s impact on the planet.
The Landsat program, managed by the USGS, has been acquiring images of the Earth’s surface since 1972. Landsat’s 40 years of critical scientific information is being fully released for the first time ever. Google Earth Engine brings together Landsats trillions of scientific measurements and makes it available online with tools for scientists, independent researchers, and nations to mine this massive warehouse of data to detect changes, map trends and quantify differences on the Earth’s surface. This data can be used for a variety of applications including detecting deforestation, classifying land cover, estimating forest biomass and carbon, and mapping the world’s roadless areas. Many more applications are waiting to be discovered.
South America Deforestration
Fractions of green vegetation, soil, and non-photosynthetic vegetation are extracted and then combined into a new index called NDFI, or Normalized Difference Fraction Index. NDFI is designed to detect not only deforestation but also forest degradation and is used in IMAZON’s SAD (Sistema de Alerta de Desmatamento) system for monitoring forest change (Source: Google)
As part of the USAID and NASA-funded CARPE (Central Africa Regional Program for the Environment) project, an exhaustive mining of the Landsat ETM+ archive was performed to map forest cover loss for the whole of the Democratic Republic of the Congo from 2000 to 2010. Forest was defined as 30% or greater canopy cover for trees of 5 meters or more in height. All such assemblages that were converted to non-forest are quantified and labeled as forest cover loss. Forest cover loss was divided into three categories, primary forest cover loss (red), secondary forest cover loss (yellow) and woodland loss (orange). Over 8,000 Landsat images were processed to make this product. A final version of this map will be the initial derived product of the Observatoire Satellital des Forêts d’Afrique Centrale’s FACET (Forêt d’Afrique Centrale Evaluée par Télédétection) product suite. (Source: Google).