Lançamos a Coleção 5 (1985-2019)

Deforestation Method

(UNDER CONSTRUCTION)

BRIEF DESCRIPTION OF THE STEPS OF THE DEFORESTATION AND REGENERATION MODULE:

Suppression of forest and natural non-forest vegetation and regeneration

1. Adjustment of coverage and usage maps to filter transitions with an area smaller than one hectare. Since the maps at the beginning of the series have more classification noise due to the reduced number of images for mosaic, considering these years to start the adjustments could generate accumulation of errors throughout the adjusted series.

Therefore, the adjustment starts by taking 2000 as the base year, in three stages:

  • Adjustment considering transitions in consecutive years in the period prior to 2000 (adjust 1985 - 1999)
  • Adjustment considering transitions in consecutive years after 2000 (adjusts 2001 - 2018)
  • Adjust the year 2000 map based on the adjusted maps for 1999 and 2001.

2. Considering the 1988 map as the basis for starting the execution of the algorithm, the deforestation and regeneration events are established by analyzing the trajectory of each pixel according to the criteria below:

      Suppression t =

      VN t-2

      VN t-1

      A t

      A t+1

      Regeneration t =

      A t-2

      A t-1

      VN t

      VN t+1

      VN t+2

      VN t+3

      Where VN corresponds to any class of vegetation (Campestre Formation, Non-Forest Wet Area, Other Non-Forest Formation, Forest Formation, Savanic Formation, Mangrove), A corresponds to any class of Anthropic Use (Annual Agriculture, Semi-perennial Agriculture, Planted Forest , Pasture, Mining, Aquaculture, Urban Infrastructure, Other Non-Vegetated Areas) and t = 1988, ..., 2018.


      3. Based on the analysis of the trajectory over the time series, the algorithm allocates each pixel in one of the classes established for the product (see color palette at the end of the document):

      Class

      Description

      Value

      Primary Veg.

      Indicates absence of deforestation event: permanence since the base year in one or more classes of Natural Vegetation or transition to class of Anthropic Use with permanence in this class for a period shorter than established (item 2.)

      2

      Primary Veg Suppression

      Indicates Deforestation event, in a given year t, in a pixel previously allocated in the Veg class. Primary, after which the pixel is allocated in the Anthropic class (in t + 1).

      4

      Recovery for Secondary Veg.

      Indicates a Regeneration event in a given year t, after which the pixel is allocated to the Secondary Veg class (at t + 1).

      5

      Secondary Veg.

      Indicates trajectory with the presence of a Recovery for Secondary Veg event in previous years.

      3

      Secondary Veg. Suppression

      Indicates Deforestation event, in a given year t, in a pixel previously allocated in the Secondary Veg class, after which the pixel is allocated in the Anthropic class (in t + 1).

      6

      Anthropic

      Indicates permanence in any class of Anthropic Use since the base year or trajectories with Primary Veg Suppression event or Secondary Veg event in previous years.

      1