[R-sig-Geo] How to translate coordinates from cylindrical to a Lambert Azimuthal Equal Area Projection

[Ivailo]

On Mon, Apr 22, 2013 at 1:14 PM, Ivailo <ubuntero.9161 at gmail.com> wrote:
>
> Dear Listmembers,
>
> I have a 40 000 x 40 000 GeoTIFF file that I need to crop to an area
> of interest (perhaps about 1000 x 1000 pixels, 25 x 25 m grid). The
> file seems to be in the Lambert Azimuthal Equal Area Projection
> (coord. ref. : +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000
> +y_0=3210000 +ellps=GRS80 +units=m +no_defs) while I use Google Earth
> (using a Cylindrical projection with a WGS84 datum) to navigate and
> delineate the extent of the area I'd like to crop from the original
> file.
>
> As I don't have much experience working with Raster* objects as
> defined in the raster package, I'd like to ask you for help in
> "translating" the coordinates I get from Google Earth (i.e., decimal
> degrees) to the ones needed to define the extent of interest for the
> RasterLayer object I have created by reading the GeoTiff file via
> `raster("myfile.tif")`.

Meanwhile I have found the "World Coordinate Converter" at
http://twcc.free.fr where I can convert single coordinate pairs from
"GPS (WGS84) (deg)" to "ETRS89/ETRS-LAEA". Yet, I would still
appreciate if somebody could provide advice how to do such an
operation on a raster object within R (or even on coordinate pairs
within a data.frame).

Cheers,
Ivailo
--
UBUNTU: a person is a person through other persons.