threshold_gfc: Threshold the GFC product

In gfcanalysis: Tools for Working with Hansen et al. Global Forest Change Dataset

Threshold the GFC product

Description

Uses the GFC data output from extract_gfc to make an thresholded layer stack with five layers: treecover2000, loss, gain, lossyear, and datamask layers. See Details for the coding used in each layer. Note that the output file format is fixed as GeoTIFF with LZW compression.

Usage

threshold_gfc(gfc, forest_threshold = 25, ...)

Arguments

gfc	extract of GFC product for a given AOI (see extract_gfc)
forest_threshold	percent woody vegetation to use as a threshold for mapping forest/non-forest
...	additional arguments as for writeRaster, such as filename or overwrite

Details

The output uses the following codes to describe forest change at each pixel:

Band 1 (forest2000)

Non-forest	0
Forest	1

Band 2 (lossyear)

No loss	0
Loss in 2001	1
Loss in 2002	2
Loss in 2003	3
Loss in 2004	4
Loss in 2005	5
Loss in 2006	6
Loss in 2007	7
Loss in 2008	8
Loss in 2009	9
Loss in 2010	10
Loss in 2011	11
Loss in 2012	12
Loss in 2013	13
Loss in 2014	14

Note that lossyear is zero for pixels that were not forested in 2000, and that the 2013 and 2014 loss layers are not available in the original 2013 Hansen dataset (the 2013 loss layer is available in the 2014 and 2015 updates, while the 2014 loss layer is available in the 2015 update only).

Band 3 (gain)

No gain	0
Gain	1

Note that gain is zero for pixels that were forested in 2000

Band 4 (lossgain)

No loss and gain	0
Loss and gain	1

Note that loss and gain is difficult to interpret from the thresholded product, as the original GFC product does not provide information on the sequence (loss then gain, or gain then loss), or the levels of canopy cover reached prior to loss (for gain then loss) or after loss (for loss then gain pixels). The layer is calculated here as: lossgain <- gain & (lossyear != 0), where loss year and gain are the original GFC gain and lossyear layers, respectively.

Band 5 (datamask)

No data	0
Land	1
Water	2

Value

RasterBrick with thresholded GFC product (see details above)

See Also

extract_gfc

gfcanalysis documentation built on Oct. 11, 2023, 5:15 p.m.