[R-sig-Geo] Proj4string for NASA GPW v3 and Blue Marble world city light map?

[Alex Mandel]

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
>>>