For the manipulation of spatial objects and spatial analyses, I mainly use R, meaning that I use R packages that turn R into a powerful Geographic Information System (GIS). Before 2017, I was using sp, rgdal, rgeos for vector objects and raster for raster objects. Now I use a combination of sf (created to replace sp, rgoes and rgdal), raster and sf and mapview.

One of the most common manipulation is to convert coordinates (see sf::st_transform() in raster::projectRaster()). With my previous set up one one of the main difficulty was to find the right proj4 string, For instance, to use UTM for the zone 17N, with rgdal I used to write:

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rgdal::spTransform(
  mysp,
  CRS("NAD 83 +proj=utm +zone=17 +ellps=GRS80 +datum=NAD83 +units=m +no_defs")
)

Now sf makes things way easier with the use the code defined by the European Petroleum Survey Group. So now I write:

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st_transform(mysf, crs = 26917)

Pretty neat! Also, I’d like to mention https://epsg.io/ that makes the search of a specific projection very efficient. For instance, if you search for “Ontario NAD27 UTM”, you’ll end up on https://epsg.io/26717, extremely helpful!