Rnightlights (version 0.1.2)

processNLCountry: Processes nightlights for an individual country in a particular nlPeriod

Description

Given a countryCode, yearMonth and preferred processing methods cropMaskMethod and extractMethod, this function will first check if the data already exists in the cache. First it will check if the data file exists and if it does not it will create a dataframe of the country data containing only the administrative properties and move to processing. If the data file exists it will check to see if the particular year month already exists. If it exists, it will exit with a message. If it does not exist, it will load the country data file and move on to processing.

Usage

processNLCountry(ctryCode, nlPeriod, nlType,
  cropMaskMethod = pkgOptions("cropMaskMethod"),
  extractMethod = pkgOptions("extractMethod"),
  fnStats = pkgOptions("stats"))

Arguments

ctryCode

character string The ctryCode of interest

nlPeriod

character string The nlPeriod of interest

nlType

character string The nlType of interest

cropMaskMethod

("rast" or "gdal") Whether to use rasterize or gdal-based functions to crop and mask the country rasters

extractMethod

("rast" or "gdal") Whether to use rasterize or gdal-based functions to crop and mask the country rasters

fnStats

the statistics to calculate. If not provided will calculate the stats specified in pkgOptions("stats")

Value

None

Details

Processing consists of:

1. Reading in the country polygon in ESRI Shapefile format

2. Reading in the tiles that the particular country intersects with and then clipping the tile(s) to the country boundary

3. Extract the data from the clipped raster and compute various statistics at the lowest admin level in the country.

4. Finally, these stats are appended to the data frame and written to the data file.

NOTE: processNLCountry() assumes that all inputs are available and will not attempt to download them. It should ideally be called from the function processNlData() which does all the preparation for processing. processNlData() which can process multiple countries and time periods will download all the required tiles and polygons prior to calling processnlcountry. getCtryNlData can also be used with the option ignoreMissing=FALSE which will call processNlData in the background.

Examples

# NOT RUN {
#calculate only the sum of VIIRS radiances for Dec 2012 using gdal
#for both cropMask and extraction for KEN
# }
# NOT RUN {
processNLCountry("KEN", "201212", "VIIRS", "gdal", "gdal", "sum")
# }
# NOT RUN {
# }