[R-sig-Geo] WKT coordinate system string (PRJ) to PROJ.4

Michael Sumner mdsumner at gmail.com
Tue Jan 5 12:28:14 CET 2016


On Tue, 5 Jan 2016 at 22:22 Roger Bivand <Roger.Bivand at nhh.no> wrote:
>
> On Tue, 5 Jan 2016, Michael Sumner wrote:
>
> >> On Tue, 5 Jan 2016 at 21:09 Michael Sumner <mdsumner at gmail.com> wrote:
> >
> >> Hello, is there any R-level way to convert a WKT/PRJ *coordinate
system*
> > string to
> >> PROJ.4 used by sp/rgdal?
> >
> >
> >
> > I see it in ogr_proj.cpp at line 124:
> >
> >
> > if (hSRS->exportToProj4(&pszProj4) != OGRERR_NONE) {
> >
> > Roger, Edzer: could we please expose that functionality from rgdal to
input
> > WKT from R?
>
> That is exposed - the output comes in that of ogrInfo(), but needs the DSN
> and layer too.
>
> I've committed the reverse of showWKT() as showP4() in revision 596 on
> R-Forge - let me know if you need a Windows binary to test.
>

Brilliant, thanks for the help.

I could definitely use the Windows binary, this is for a Windows-specific
task. No huge rush, just whenever that is possible would be great.

(I'm sorry about the HTML postings, I can't see how to control Google Inbox
just how I need - I've reverted to Gmail in the hope it uses real ">"
characters, and will try to remember to do so for lists).

Cheers, Mike.

>
> Roger
>
> >
> >
> > Is that feasible? I'll have a look at doing it myself . . . I know it's
a
> > distraction from other goals.
> >
> >
> > Thank you.
> >
> >
> > Cheers, Mike.
> >
> >
> >
> >> (Previously I've written out to SHP/PRJ, and read back in with rgdal,
but
> > that's obviously a
> >> bit naff.)
> >
> >
> >> (I know you can rgeos::readWKT and wkb::readWKB for *geometry*).
> >
> >
> >
> >> Cheers, Mike.
> >
> >
> >
> >
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; fax +47 55 95 91 00
> e-mail: Roger.Bivand at nhh.no

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