Message-ID: <CAPQ=hVJ3tG9biv-vfjRh=6NyiTXoNa4BeaS9JS_QzwN2DufWCw@mail.gmail.com>
Date: 2012-11-02T08:03:25Z
From: Oliver Soong
Subject: readGDAL loses datum
R 2.15.1 32-bit, rgdal 0.7.20, Windows 7.
grid <- GridTopology(c(-2100000, 1200000), c(100, 100), c(1, 1))
p4s <- CRS("+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96
+x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80
+towgs84=0,0,0")
img1 <- SpatialGridDataFrame(grid, data.frame(band1 = 1), p4s)
img1.file <- file.path(tempdir(), "img1.tif")
writeGDAL(img1, img1.file)
img2 <- readGDAL(img1.file)
img2.file <- file.path(tempdir(), "img2.tif")
writeGDAL(img2, img2.file)
img1 at proj4string
img2 at proj4string
For me, img1 at proj4string has +datum=NAD83 and img2 at proj4string does
not. Not surprisingly, if I look at both files in Arc, img1 has a
defined datum and img2 does not.
Am I doing anything wrong?
Oliver