nightlight_apply: Apply a function to each geometric object

In altaf-ali/nightlight: R package for working with NOAA night light data

Description

nightlight_apply applies a function over each geometric object in geom for each year of nightlight data in nightlight_data

Usage

nightlight_apply(nightlight_data, geom, func, ...)

Arguments

nightlight_data	source path where nightlight data was downloaded
geom	geometric object
func	function to apply
...	arguments passed to func

Examples

library(nightlight)

set the root folder for where you want to download the dataset
NOAA_DATASET_ROOT <- "~/datasets/noaa"

nightlight_download(NOAA_DATASET_ROOT)

nightlight_data <- nightlight_load(NOAA_DATASET_ROOT)

create a polygon for testing
coordinates <- matrix(
  c(
    113.4789, 22.19556,
    113.4811, 22.21748,
    113.4941, 22.24155,
    113.5271, 22.24595,
    113.5481, 22.22261,
    113.5455, 22.22148,
    113.4988, 22.20166,
    113.4842, 22.19775,
    113.4789, 22.19556
  ),
  ncol = 2,
  byrow = TRUE
)
polygon <- Polygon(coordinates)

spatial_polygons <- SpatialPolygons(list(Polygons(list(polygon),1)))

results <- nightlight_apply(nightlight_data, c(spatial_polygons), mean, na.rm = TRUE)

print(results)

altaf-ali/nightlight documentation built on May 11, 2019, 11:29 p.m.