Bugfix: read_regnie gave wrong extent

Author: eduardszoecs

DESCRIPTION

@@ -2,7 +2,7 @@ Package: esmisc
 Type: Package
 Title: Misc Functions of Eduard Szöcs
 Version: 0.0.3.9002
-Date: 2017-01-10
+Date: 2017-03-30
 Authors@R: c(person("Eduard", "Szöcs", role = c("aut", "cre"),
     email = "[email protected]"))
 Maintainer: Eduard Szöcs <[email protected]>

NEWS

@@ -11,6 +11,8 @@ MINOR IMPROVEMENTS
 
 BUG FIXES
 
+* read_regnie() gave wrong extent (reported by Tim Haering).
+
 DEPRECATED FUNCTIONS
 
 DEFUNCT FUNCTIONS

R/read_regnie.R

@@ -5,7 +5,7 @@
 #' \url{https://www.dwd.de/DE/leistungen/regnie/download/regnie_beschreibung_pdf.pdf?__blob=publicationFile&v=2}.
 #' Data is available here: \url{ftp://ftp-cdc.dwd.de/pub/CDC/grids_germany/daily/regnie/}.
 #' @import raster readr
-#' @param file path to gz archive
+#' @param file path to gz archive.
 #' @return A \code{RasterLayer} object.
 #' @export
 #' @examples
@@ -18,14 +18,13 @@ read_regnie <- function(file){
                    n_max = 971, 
                    na = '-999')
   r <- raster(as.matrix(cont))
-  # ymax = (55 + 10 / 120)                    = 55.083333
-  # ymin = (55 + 10 / 120) - (971 - 1) / 120  = 47
-  # xmin = (6 - 10 / 60)                      = 5.833333
-  # xmax = (6 - 10 / 60) + (611 - 1) / 60     = 16
-  extent(r) <- c(6 - 10 / 60, 
-                 (6 - 10 / 60) + (611 - 1) / 60, 
-                 (55 + 10 / 120) - (971 - 1) / 120, 
-                 55 + 10 / 120)
+  
+  xdelta <- 1/60
+  ydelta <- 1/120
+  extent(r) <- c(6 - 10 * xdelta - xdelta / 2, 
+                 (6 - 10 * xdelta) + (611 - 1) * xdelta + xdelta / 2, 
+                 (55 + 10 * ydelta) - (971 - 1) * ydelta - ydelta / 2, 
+                 55 + 10 * ydelta + ydelta / 2)
   crs(r) <- "+proj=longlat"
   # scale to mm
   r <- r/10

tests/testthat.R

@@ -1,3 +1,5 @@
 library('testthat')
 library('esmisc')
+library('raster')
+
 test_check("esmisc")

tests/testthat/test-read_regnie.R

@@ -9,5 +9,10 @@ test_that('read_regnie works', {
   expect_true(is.na(r[1]))
   expect_equivalent(r[438537], 109.1)
   expect_equivalent(r[100000], 5.7)
+  expect_equal(as.matrix(extent(r)), 
+               structure(c(5.825, 46.9958333333333, 16.0083333333333, 55.0875), 
+                         .Dim = c(2L, 2L), 
+                         .Dimnames = list(c("x", "y"), c("min", "max")))
+  )
 })