[R] Coordinate projection with proj4R: the Albers Equal-Area Conic projection?

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From: Slist (slist@oomvanlieshout.net)
Date: Tue 11 May 2004 - 06:55:04 EST


Message-id: <6.1.0.6.0.20040510222350.02568be8@localhost>

Hi all!

I am trying to project coordinates collected by GPS collars. The data is in
decimal degrees and provides locations for two Sable antelope running
around in Kruger NP South Africa.

After a wide search it seems that proj4R provides most options for
projection of coordinates. However I can not get around the following error
message when I try to project my coordinates using the Albers Equal Area
Conic projection.

According to the proj4 pages, the following parameters should be supplied:
http://www.remotesensing.org/geotiff/proj_list/albers_equal_area_conic.html
PROJ.4 Organization
   +proj=aea +lat_1=Latitude of first standard parallel
               +lat_2=Latitude of second standard parallel
               +lat_0=Latitude of false origin
               +lon_0=Longitude of false origin
               +x_0=Easting of false origin
               +y_0=Northing of false origin

But when running the command in R, I get the following error message

> library(proj4R)
>
> res <- project(cbind(x, y), "+proj=aea +lon_0=24 +lat_0=0 +lat_1=18s
+lat_2=32s +x_0=0 +y_0=0 ") #
Error in project(cbind(x, y), "+proj=aea +lon_0=24 +lat_0=0 +lat_1=18s
+lat_2=32s +x_0=0 +y_0=0 ") :
         major axis or radius = 0 or not given
>

I have also tried:
> res <- project(cbind(x, y), "+proj=aea +lon_0=24 +lat_0=0 +lat_1=-18
+lat_2=-32 +x_0=0 +y_0=0 ") #
with the same error.

Any suggestions?

Thanks,

Sander.

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