Skip to content

Instantly share code, notes, and snippets.

@valentinitnelav

valentinitnelav/Euclidean_buffer_distortions.R

Created August 2, 2017 22:20
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save valentinitnelav/bdea511468eed337440ab2f2bc12c000 to your computer and use it in GitHub Desktop.
Save valentinitnelav/bdea511468eed337440ab2f2bc12c000 to your computer and use it in GitHub Desktop.
Download ZIP
Euclidean buffer - distortions
Raw
Euclidean_buffer_distortions.R
require(rgeos)
require(sp)
require(plotKML)
# Generate a random grid-points for a (almost) global bounding box
b.box <- as(raster::extent(120, -120, -60, 60), "SpatialPolygons")
proj4string(b.box) <- "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
set.seed(2017)
pts <- sp::spsample(b.box, n=100, type="regular")
plot(pts@coords)
# Project to Mollweide projection to be able to apply buffer with `gBuffer`
# (one could use other projection)
pts.moll <- sp::spTransform(pts, CRSobj = "+proj=moll")
# create 1000 km buffers around the points
buf1000km.moll <- rgeos::gBuffer(spgeom = pts.moll, byid = TRUE, width = 10^6)
plot(buf1000km.moll)
# convert back to WGS84 unprojected
buf1000km.WGS84 <- sp::spTransform(buf1000km.moll, CRSobj = proj4string(pts))
plot(buf1000km.WGS84) # distorsions are present
# save as KML to visualize distorted Euclidian buffers on Google Earth
plotKML::kml(buf1000km.WGS84, file.name = "buf1000km.WGS84.kml")
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment