GSIF (version 0.5-3)

extract: Extracts values at points from a list of files

Description

Overlays and extracts values at points from a list of raster layers defined as file names (e.g. GeoTiffs). Extends the extract function from the raster package. Especially suitable for extracting values of a large list of rasters that have not been organized into a mosaick (a virtual stack), for example a list of Landsat scenes.

Usage

"extract"(x, y,  path=".", ID = "SOURCEID",  method = "simple", is.pattern = FALSE, force.projection = TRUE,  NAflag = "", show.progress=TRUE, isFactor=FALSE, ...)
"extract"(x, y,  path = ".", ID = "SOURCEID",  method = "simple", is.pattern = FALSE, force.projection = TRUE,  NAflag = "", show.progress=TRUE, isFactor=FALSE, ...)

Arguments

x

object of class "SpatialPoints*"

y

character; list of files that can be read using the raster function

path

optional working directory where the files are stored

ID

character; column name for the unique identifier (if object is of class "SpatialPoints" "SOURCEID" column is automatically generated)

method

character; resampling method (see raster::extract)

is.pattern

logical; specifies whether the list is a pattern

force.projection

logical; specifies whether the reprojection should be ignored

NAflag

character; missing value flag (all missing values are removed by default)

show.progress

logical; specifies whether to display the progress bar

isFactor

logical; turns aggregation on off for factor type variable

...

additional arguments that can be passed to the raster::extract function

See Also

raster::extract, warp