Proj4string for NASA GPW v3 and Blue Marble world city light map?

Specifically,

http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density/metadata#Spatial_Reference_Information

The answer is EPSG:4326
http://epsg.io/4326 (compare this to the info above)

CRS("+init=epsg:4326")

will do, no need for the whole proj string.

This is often the case with world wide data sets.

Enjoy,
Alex

On 05/08/2015 07:36 AM, Eric Carr wrote:

They also have this page:

http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density/metadata

On Thu, May 7, 2015 at 11:11 AM, Shaun Walbridge <SWalbridge at esri.com>
wrote:

The specific projection information is contained within the raster
datasets you download, in the related ASCII, Bil or GRID file. The
metadata you see on that page is just a human readable representation of
the data coverage, not intended to directly map to the full spatial
reference.

--
Shaun Walbridge
GIS Developer




On 5/7/15, 5:15 AM, "Ziyu Ma" <paul.ziyu.ma at gmail.com> wrote:

Dear all,

I was working with a project concerning human population, using data

from

the Population Density Grid, version 3.

I have hard time understanding the spatial reference from this metadata
page:

http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density/metada

ta

Can I translate this into a proj4string so that I can use it as a CRS

in

R?

Also, just out of curiosity, what it the spatial reference for NASA's

Blue

Marble maps, like the famous world city light map? Can I also use a
proj4string to describe it?

Thank you very much.

Cheers,
Ma

Ziyu Ma
PhD Student
Ecoinformatics & Biodiversity,
Department of Bioscience, Aarhus University
Ny Munkegade 114, DK-8000 Aarhus C, Denmark