setRasclassData: Add data from dataframe to rasclass object

In rasclass: Supervised Raster Image Classification

Description

This function adds data from a dataframe to an existing rasclass-class object.

Usage

setRasclassData(newdata, object = new('rasclass'), ncols = NA, nrows = NA,
	xllcorner = NA, yllcorner = NA, cellsize = NA, NAvalue = NA,
	samplename = 'sample')

Arguments

newdata	A data frame containing raster cell values in its columns.
object	An optional rasclass object where the data should be updated to, a new object is created if not specified.
ncols	The number of columns of the raster grid. Optional if the values are already specified in the rasclass object.
nrows	The number of rows of the raster grid. Optional if the values are already specified in the rasclass object.
xllcorner	Coordinates of the X coordinate of the lower left corner. Optional if the values are already specified in the rasclass object.
yllcorner	Coordinates of the Y coordinate of the lower left corner. Optional if the values are already specified in the rasclass object.
cellsize	The cell size of the grid. Optional if the values are already specified in the rasclass object.
NAvalue	The value in the raster that represents NA values. Optional if the values are already specified in the rasclass object.
samplename	Optional name of the column in the input data frame that will be used as sample data. The default is 'sample'.

Details

This function adds data from a dataframe to a rasclass object for subsequent classification using the classifiers from the rasclass package. Similar to the readRasterFolder, the name of the column containing the sample data has to be specified. The default sample column name is "sample".

The data in the input dataframe is assumed to be from raster files with the same projection, grid size and location. For ascii files this is equivalent to having an identical header in all the layers. If the common header has not been specified in the gridSkeleton slot of the input object before, the values have to be given as arguments to the function.

Value

A rasclass-class object containing the loaded data as a dataframe in the data slot.

Memory Issues

The setRasclassData function only keeps track of data raster cells that have an observed value (non-NA) in every column of the input dataframe provided. The resulting grid structure will be retained in the gridSkeleton slot.

See Also

rasclass-package, rasclass-class, rasclassRaster-class,

readRaster, writeRaster,

readRasterFolder,

buildFormula, checkRasclass,

rasclassMlc, classifyRasclass

Examples

# For this example, create artificial data
mysample <- c(rep(rep(c(1,2), each = 25), 25), rep(rep(c(3,4), each = 25), 25))
mysample <- mysample + sample(c(0, NA), 2500, replace = TRUE, prob = c(1, 10))
myvar1 <- rep(1:50, each = 50) + rnorm(2500, 0, 5)
myvar2 <- rep(rep(1:50), 50) + rnorm(2500, 0, 5)
newdata <- data.frame(mysample, myvar1, myvar2)

# Prepare a rasclass object using the dataframe and specifying raster properties
object <- new('rasclass')
object <- setRasclassData(newdata, ncols = 50, nrows = 50,
	xllcorner = 0, yllcorner = 0, cellsize = 1, NAvalue = -9999,
	samplename = 'mysample')

# Summarize the rasclass object
summary(object)

rasclass documentation built on May 2, 2019, 6:11 a.m.