fnAggRadGdal: Calculate zonal statistics using GDAL

In chrisvwn/Rnightlights: Satellite Nightlight Data Extraction

Description

Calculate zonal statistics using GDAL. Alternative to fnAggRadRast and faster. Modified from http://www.guru-gis.net/efficient-zonal-statistics-using-r-and-gdal/

Usage

fnAggRadGdal(
  ctryCode,
  admLevel,
  ctryPoly,
  nlType,
  configName = pkgOptions(paste0("configName_", nlType)),
  extension,
  multiTileStrategy = pkgOptions("multiTileStrategy"),
  multiTileMergeFun = pkgOptions("multiTileMergeFun"),
  removeGasFlaresMethod = pkgOptions(paste0("removeGasFlaresMethod_", nlType)),
  nlPeriod,
  nlStats = pkgOptions("nlStats"),
  gadmVersion = pkgOptions("gadmVersion"),
  gadmPolyType = pkgOptions("gadmPolyType"),
  custPolyPath = NULL
)

Arguments

ctryCode	character string the ISO3 country code to be processed
admLevel	character string The admin level to process. Should match the ctryPoly given but no checks are made currently.
ctryPoly	Polygon the loaded country polygon layer
nlType	the nlType of interest
configName	character the config short name of raster being processed
extension	character the extension of raster being processed
multiTileStrategy	character How to handle multiple tiles per nlPeriod
multiTileMergeFun	character The function to use to merge tiles
removeGasFlaresMethod	logical Whether to perform gas flare removal pre-processing
nlPeriod	character string the nlPeriod to be processed
nlStats	character vector The stats to calculate
gadmVersion	The GADM version to use
gadmPolyType	The format of polygons to download from GADM
custPolyPath	Alternative to GADM. A path to a custom shapefile zip

Value

data.frame of polygon attributes and the calculated stats, one column per stat

Examples

#read the Kenya polygon downloaded from GADM and load the lowest admin level (ward)
## Not run: 
ctryPoly <- readCtryPolyAdmLayer(ctryCode="KEN",
    Rnightlights:::getCtryShpLowestLyrNames(ctryCodes="KEN"))

#calculate the sum of radiances for the wards in Kenya
sumAvgRadRast <- Rnightlights:::fnAggRadGdal(ctryCode="KEN", ctryPoly=ctryPoly,
    nlType="VIIRS.M", nlPeriod="201401", nlStats=c("sum","mean"))

## End(Not run)

chrisvwn/Rnightlights documentation built on Sept. 7, 2021, 1:44 a.m.