[R] sp: proj4string has no impact

Albrecht Kauffmann alkauffm at rz.uni-potsdam.de
Wed Jan 17 17:34:07 CET 2007


Hi all,

I'm faced with a problem applying the sp package: The projection argument in

readShapePoly(Shapefile,proj4string="CRS class argument")

e.g.: CRS("+proj=aea +lat_1=46 +lat_2=73 +lat_0=60 +lon_0=84 +x_0=0
+y_0=0 +ellps=clrk66 +units=m  +no_defs")

doesn't have any impact on the plotted object. I also tested the simple
example:

xy = cbind(x = 2 * runif(100) - 1, y = 2 * runif(100) - 1)
plot(SpatialPoints(xy, proj4string =
CRS("+proj=longlat")),xlim=c(-1,1),ylim=c(-1,1))

looks exactly like

plot(SpatialPoints(xy, proj4string =CRS("+proj=stere +lon_0=98  +over"))

or

plot(SpatialPoints(xy))

without any projection.

What I'm doing wrong?

I use the latest versions of sp and rgdal.

With many thanks for any hint,

Albrecht Kauffmann
Potsdam University



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