R/qgis_rasterlayerzonalstats.R

In JanCaha/r_package_qgis: An extension of package "qgisprocess" providing direct R functions for QGIS functions

##' QGIS Algorithm provided by QGIS (native c++) Raster layer zonal statistics (native:rasterlayerzonalstats). Calculates statistics for a raster layer's values, categorized by zones defined in another raster layer. This algorithm calculates statistics for a raster layer's values, categorized by zones defined in another raster layer.  If the reference layer parameter is set to "Input layer", then zones are determined by sampling the zone raster layer value at the centroid of each pixel from the source raster layer.  If the reference layer parameter is set to "Zones layer", then the input raster layer will be sampled at the centroid of each pixel from the zones raster layer.  If either the source raster layer or the zone raster layer value is NoData for a pixel, that pixel's value will be skipped and not included in the calculated statistics.
##'
##' @title QGIS algorithm - Raster layer zonal statistics
##'
##' @param INPUT `raster` - Input layer. Path to a raster layer.
##' @param BAND `band` - Band number. Integer value representing an existing raster band number.
##' @param ZONES `raster` - Zones layer. Path to a raster layer.
##' @param ZONES_BAND `band` - Zones band number. Integer value representing an existing raster band number.
##' @param REF_LAYER `enum`  of `("Input layer", "Zones layer")` - Reference layer. Number of selected option, e.g. '1'. Comma separated list of options, e.g. '1,3'.
##' @param OUTPUT_TABLE `sink` - Statistics. Path for new vector layer.
##' @param ... further parameters passed to `qgisprocess::qgis_run_algorithm()`
##' @param .complete_output logical specifying if complete out of `qgisprocess::qgis_run_algorithm()` should be used (`TRUE`) or first output (most likely the main) should read (`FALSE`). Default value is `TRUE`.
##' @param .quiet logical specifying if parameter `.quiet` for `qgisprocess::qgis_run_algorithm()` Default value is `TRUE`.
##' @param .messages logical specifying if messages from `qgisprocess::qgis_run_algorithm()` should be printed (`TRUE`) or not (`FALSE`). Default value is `FALSE`.
##'
##' @details
##' ## Outputs description
##' * CRS_AUTHID - outputString - CRS authority identifier
##' * EXTENT - outputString - Extent
##' * HEIGHT_IN_PIXELS - outputNumber - Height in pixels
##' * NODATA_PIXEL_COUNT - outputNumber - NoData pixel count
##' * OUTPUT_TABLE - outputVector - Statistics
##' * TOTAL_PIXEL_COUNT - outputNumber - Total pixel count
##' * WIDTH_IN_PIXELS - outputNumber - Width in pixels
##'
##'
##' @export
##' @md
##' @importFrom qgisprocess qgis_run_algorithm

qgis_rasterlayerzonalstats <- function(INPUT = qgisprocess:::qgis_default_value(), BAND = qgisprocess:::qgis_default_value(), ZONES = qgisprocess:::qgis_default_value(), ZONES_BAND = qgisprocess:::qgis_default_value(), REF_LAYER = qgisprocess:::qgis_default_value(), OUTPUT_TABLE = qgisprocess:::qgis_default_value(),..., .complete_output = .complete_output_option(), .quiet = .quiet_option(), .messages = .message_option()) {

  check_algorithm_necessities("native:rasterlayerzonalstats")

  if (.messages){
    output <- qgisprocess::qgis_run_algorithm("native:rasterlayerzonalstats", `INPUT` = INPUT, `BAND` = BAND, `ZONES` = ZONES, `ZONES_BAND` = ZONES_BAND, `REF_LAYER` = REF_LAYER, `OUTPUT_TABLE` = OUTPUT_TABLE,..., .quiet = .quiet)
  } else {
    suppressMessages(
      output <- qgisprocess::qgis_run_algorithm("native:rasterlayerzonalstats", `INPUT` = INPUT, `BAND` = BAND, `ZONES` = ZONES, `ZONES_BAND` = ZONES_BAND, `REF_LAYER` = REF_LAYER, `OUTPUT_TABLE` = OUTPUT_TABLE,..., .quiet = .quiet)
      )
  }

  if (.complete_output) {
    return(output)
  }
  else{
    qgisprocess::qgis_extract_output(output, "CRS_AUTHID")
  }
}