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

[Ziyu Ma]

Thank you all very much. This was very helpful!

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


On Sat, May 9, 2015 at 3:56 AM, Alex Mandel <tech_dev at wildintellect.com>
wrote:

> 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
> >>>
>
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