reclass_rast: reclassify values of a raster

In IREA-CNR-MI/sprawl: sprawl: Spatial Processing (in) R: Advanced Workflows Library

Description

function to reclassify values of a raster object or raster file based on a reclassification matrix which specifies which value in the output should be taken by different intervals of values of the input raster (simple wrapper for the raster::reclassify function, providing a (somehow) easier and extended I/O functionality)

Usage

reclass_rast(in_rast, reclass_matrix, to_file = FALSE, out_rast = NULL,
  overwrite = FALSE)

Arguments

in_rast	Input raster file or "R" raster layer to be reclassified
reclass_matrix	data.frame 3 column data frame with column names equal to start, end and new Each line specifies an intervals of values in the original raster and the value they will assume in the output. See Details. IMPORTANT ! Intervals in reclass_matrix will be considered as CLOSED on THE LEFT and OPEN ON THE RIGHT ! - see examples !!!! -
to_file	logical If TRUE, the reclassified raster is saved to a tiff file and its name is returned to the caller, Default: TRUE
out_rast	character Name of the output raster file. If NULL and to_file == TRUE , the raster is saved to a file in the R temporary folder in "R" tempdir(), Default: NULL
overwrite	logical If TRUE and 'out_rast“ already exists, the file is overwritten, Default: FALSE

Details

reclass_matrix must be a 3-columns data.frame (or similar), including the start, end and new columns. It can be easily created by, for example:

reclass_matrix <- tribble(~start, ~end, ~new,
                               0,    1,   NA, # values >=0 and < 1 will be set to NA
                               1,    5,   1,  # values >=1 and < 5 will be set to 1
                               5,    7,   2,  # values >=5 and < 7 will be set to 2
                             ...,  ..., ...,
                             ...,  ..., ...,
                              11, 100, NA)   # values >=11 and < 100 will be set to NA

, or:

reclass_matrix <- data.frame(start = c(0,  1, 5, ..., ..., 11),
                             end   = c(1,  5, 7, ..., ..., 100),
                             new   = c(NA, 1, 2, ..., ..., NA)

Value

• if to_file == FALSE: *raster corresponding to the reclassified raster

• if to_file == TRUE: name of the file where it was saved (either corresponding to out_rast or to the name of the temporary file created (if out_rast == NULL))

See Also

reclassify

Examples

## Not run: 
# reclassify a land cover map with N classes to a 0-1 mask, retaining classes 5 and 9, putting
# the rest to 0 and values >= 11 to NA
# Open  the masking file
in_mask <- raster(in_maskfile)
# setup the reclassification matrix

 reclass_matrix <- tibble::tribble(
                ~start, ~end, ~new,
                     0,   0,   NA,
                     1,   5,   0,
                     5,   6,   1,
                     6,   9,   1,
                     9,  11,   1,
                     11, 100, NA)

reclass_file = "/home/lb/Temp/buttami/pippo_reclass.tif"
outmask = reclass_rast(in_rast,
                       reclass_matrix,
                       r_out = TRUE)
plot(outmask)

## End(Not run)

IREA-CNR-MI/sprawl documentation built on May 27, 2019, 1:12 p.m.