R/shortcuts.R

In jhollist/proj4shortcut:

#' Web Mercator proj.4 string
#' 
#' Shortcut that provides a proj.4 string
#' 
#' @export
web_mercator <- "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs"

#' Geographic, decimal degrees, wgs84 proj.4 string
#' 
#' Shortcut that provides a proj.4 string
#' 
#' @export
geo_wgs84 <- "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"

#' USGS Albers Equal Area Projection proj.4 string
#' 
#' Shortcut that provides a proj.4 string
#' 
#' @export
usgs_albers <- "+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=37.5 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs"

#' BC Albers Equal Area Projection proj.4 string for British Columbia
#' 
#' Shortcut that provides a proj.4 string
#' 
#' @export
bc_albers <- "+proj=aea +lat_1=50 +lat_2=58.5 +lat_0=45 +lon_0=-126 +x_0=1000000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"

#' ETRS89 Lambert Azimuthal Equal Area Projection proj.4 string for Europe
#' 
#' Shortcut that provides a proj.4 string
#' 
#' @export
etrs_laea <- "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m +no_defs"

#' UTM zone projection with wgs84 proj.4 string
#'
#' Shortcut that provides a proj.4 string 
#' 
#' @param zone chr string of UTM zone
#' 
#' @export
#' 
#' @examples 
#' utm_wgs84('10')
utm_wgs84 <- function(zone){
  
  out <- paste0("+proj=utm +zone=", zone, " +ellps=WGS84 +datum=WGS84 +no_defs")
  
  return(out)
  
}