added function points_elided() which should convert the Alaska and Hawaii areas of a SpatialPoints object to the elided portion in this package

NAMESPACE

@@ -1,6 +1,7 @@
 # Generated by roxygen2: do not edit by hand
 
 export(counties_composite)
+export(points_elided)
 export(us_aeqd_proj)
 export(us_eqdc_proj)
 export(us_laea_proj)

R/points_elided.R

@@ -0,0 +1,56 @@
+#' Shift points around Alaska and Hawaii to the elided area
+#'
+#' This function will take a SpatialPoints object and shift the points around
+#'  Alaska and Hawaii to the elided area from this package.
+#'
+#' @param sp An object of SpatialPoints class
+#' @return An elided version of the original SpatialPoints class
+#' @export
+points_elided <- function(sp){
+  orig_proj <- sp::proj4string(sp)
+  # convert it to Albers equal area
+  sp <- sp::spTransform(sp, CRS("+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +a=6370997 +b=6370997 +units=m +no_defs"))
+
+  ak_bb   <- readRDS(system.file("extdata/alaska_bb.rda", package="albersusa"))
+  #ak_bb   <- readRDS("inst/extdata/alaska_bb.rda")
+  ak_poly <- as(raster::extent(as.vector(t(ak_bb))), "SpatialPolygons")
+  sp::proj4string(ak_poly) <- "+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +a=6370997 +b=6370997 +units=m +no_defs"
+
+  # Determine which points fall in the Alaska bounding box, subset and remove
+  #  from the original points
+  ak_l <- sp::over(sp, ak_poly)
+  ak   <- sp[!is.na(ak_l),]
+  sp   <- sp[is.na(ak_l),]
+
+  # Elide the points, the key here is to set "bb" to what the original
+  #  transformation's bounding box was!
+  ak    <- maptools::elide(ak,
+                           scale=max(apply(ak_bb, 1, diff)) / 2.3,
+                           rotate = -50,
+                           bb = ak_bb) # NEED the bb option here
+  ak    <- maptools::elide(ak, shift = c(-1298669, -3018809)) # bb doesn't matter
+  sp::proj4string(ak) <- sp::proj4string(sp)
+
+  hi_bb <- readRDS(system.file("extdata/hawaii_bb.rda", package="albersusa"))
+  #hi_bb   <- readRDS("inst/extdata/hawaii_bb.rda")
+  hi_poly <- as(raster::extent(as.vector(t(hi_bb))), "SpatialPolygons")
+  sp::proj4string(hi_poly) <- "+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +a=6370997 +b=6370997 +units=m +no_defs"
+
+  # Determine which points fall in the Alaska bounding box, subset and remove
+  #  from the original points
+  hi_l <- sp::over(sp, hi_poly)
+  hi   <- sp[!is.na(hi_l),]
+  sp   <- sp[is.na(hi_l),]
+
+  hi    <- maptools::elide(hi,
+                           rotate = -35,
+                           bb = hi_bb) # NEED the bb option here
+  hi    <- maptools::elide(hi, shift = c(5400000, -1400000)) # bb doesn't matter
+  sp::proj4string(hi) <- sp::proj4string(sp)
+
+  # Bring them back together with original projection
+  sp <- rbind(sp, ak, hi)
+  sp <- sp::spTransform(sp, CRS(orig_proj))
+
+  return(sp)
+}

man/albersusa.Rd

@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/albersusa-package.r
+% Please edit documentation in R/albersusa-package.R
 \docType{package}
 \name{albersusa}
 \alias{albersusa}

man/points_elided.Rd

@@ -0,0 +1,19 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/points_elided.R
+\name{points_elided}
+\alias{points_elided}
+\title{Shift points around Alaska and Hawaii to the elided area}
+\usage{
+points_elided(sp)
+}
+\arguments{
+\item{sp}{An object of SpatialPoints class}
+}
+\value{
+An elided version of the original SpatialPoints class
+}
+\description{
+This function will take a SpatialPoints object and shift the points around
+ Alaska and Hawaii to the elided area from this package.
+}
+

man/usa_composite.Rd

@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/albersusa.r
+% Please edit documentation in R/albersusa.R
 \name{usa_composite}
 \alias{usa_composite}
 \title{Retreive a U.S. state composite map, optionally with a projection}