data-raw/ps.locations.intersect.SRTM.terrain.wallonia.90m.points_sf.R

In pokyah/agrometeoR-mlr: Collection of custom functions regularly used in my R developments, especially for the Agromet Project

#'---
#'author: "Thomas Goossens (CRA-W) - hello.pokyah@gmail.com"
#'output:
#'  html_document:
#'    theme: default
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#'title: "Extract raster data at the location of physical stations with a buffer"
#'date: "20 June, 2018"
#'---

# inspired from http://mbjoseph.github.io/2014/11/08/nlcd.html

load("./data/ps.locations.wallonia.points_sf.rda")
load("./data/data_source.SRTM.terrain.wallonia.90m.ras.rda")

# reproject the raster in the same CRS as ps points
data_source.SRTM_terrain.wallonia.90m.ras <- raster::projectRaster(
  data_source.SRTM_terrain.wallonia.90m.ras,
  crs = (sf::st_crs(ps.locations.wallonia.points_sf))$proj4string
  )

# intersecting raster with sf is not yet possible so extracting with sp. The result is a list !
ps.locations.wallonia.points_sp <- as(vs.grid.1km.wallonia.points_sf,"Spatial")

# https://gis.stackexchange.com/questions/237133/function-sample-code-to-extract-raster-value-per-polygon-in-r
raster.extracted.df <- extract(
  data_source.SRTM_terrain.wallonia.90m.ras,
  ps.locations.wallonia.points_sp,
  buffer = 200,
  fun=mean,
  na.rm = TRUE,
  df=TRUE
)


ps.locations.wallonia.points_sp@data <- raster.extracted.df
ps.locations.intersect.SRTM.terrain.wallonia.90m.points_sf <- sf::st_as_sf(ps.locations.wallonia.points_sp)
devtools::use_data(ps.locations.intersect.SRTM.terrain.wallonia.90m.points_sf)


#+ ---------------------------------
#' ## Terms of service
#' The present script is available under the [GNU-GPL V3](https://www.gnu.org/licenses/gpl-3.0.en.html) license and comes with ABSOLUTELY NO WARRANTY.
#'
#' Copyright : Thomas Goossens - hello.pokyah@gmail.com 2018.
#'
#' *(This document was generated using [R software](https://www.r-project.org/) with the [knitr library](https://deanattali.com/2015/03/24/knitrs-best-hidden-gem-spin/))*.
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