mapping_environmental_action/testing_sf_plot_times.R

require(RCurl) # used for fetching reproducible datasets
require(sf) # new simplefeature data class, supercedes sp in many ways
# using GEOS 3.6.1, GDAL 2.1.3, PROJ 4.9.3
require(sp) # needed for proj4string, deprecated by sf()
require(rgdal) # version version: 1.3-6
require(rgeos) # used for buffering below
require(devtools)
require(ggplot2)

# setwd("~/Downloads/test")
# load data

transition_wgs <- read.csv(text=getURL("https://zenodo.org/record/165519/files/SCCAN_1.4.csv"))
coordinates(transition_wgs) <- c("X", "Y")
proj4string(transition_wgs) <- CRS(wgs84)
transition_sp <- spTransform(transition_wgs, bng)
transition_sf <- st_as_sf(transition, coords = c("X", "Y"), crs=27700)

# Download data as ESRI Shapefile from page at: https://gateway.snh.gov.uk/natural-spaces/dataset.jsp?dsid=SSSI

unzip("SSSI_SCOTLAND_ESRI.zip")

# # Download data as ESRI Shapefile from page at: http://data-forestry.opendata.arcgis.com/datasets/3cb1abc185a247a48b9d53e4c4a8be87_0

unzip("National_Forest_Inventory_Woodland_Scotland_2017.zip")

sssi_sf <- st_read("./data/SSSI_SCOTLAND.shp")
sssi_sp <- readOGR("./data", "SSSI_SCOTLAND") 

forest_inventory_sf <- st_read("./data/National_Forest_Inventory_Woodland_Scotland_2017.shp")
forest_inventory_sp <- readOGR("./data", "National_Forest_Inventory_Woodland_Scotland_2017") 

# Test validity of geometry

rgeos::gIsValid(sssi_sp) 
valid <- st_is_valid(sssi_sf)
  valid[valid == FALSE]

# Alternative approach from stackexchange using simplified geometry
  
  sssi_sp2 <- rgeos::gSimplify(sssi_sp, tol=3)
  par(mfrow=c(1,2))
  plot(sssi_sp[1,])
  plot(sssi_sp2[1,])
  
  system.time(
    sssi_b1000 <- rgeos::gBuffer(sssi_sp2, width = 20, quadsegs = 30)
  )  
  
  sssi_sf2 <- sf::st_simplify(sssi_sf)
  system.time(
    sssi_b1000 <- sf::st_buffer(sssi_sf2, dist = 20)
  ) 
  
# Render ggplot2 plot on simplified geometry

ggplot(sssi_sf2) + geom_sf(aes(fill = PA_CODE))
plot(sssi_sf2)

# First test out plots using spatialfeatures and spdf with core R

system.time(
plot(sssi_sf2)
  )

system.time(
  plot()
  )

system.time(
plot(sssi_sp)
  )

# First test out plots using spatialfeatures and spdf with ggplot2

system.time(
  ggplot() +
    geom_sf(data = sssi_sf)
)

system.time(
  ggplot() +
    geom_polygon(data = sssi_sp)
)
# Now try to run a count within a buffer:

st_crs(sssi_sf) <- 27700
st_crs(transition_sf) <- 27700

# CRS uses meters for units, so buffer here should be a modest 50m:

count_data_sf <- sum(apply(st_within(points_sf, st_buffer(sssi, dist = 50), sparse=FALSE), 1, any))

# count_data_sf <- sum(apply(gWithin(points_sf, gBuffer(sssi,width=50)
  
sessioninfo::session_info()