[R-sig-Geo] Defining CRS when loading a raster doesn't seems to work anymore

Michael Sumner mdsumner at gmail.com
Tue Nov 19 16:36:57 CET 2013


Whoops, sorry for my off-track mis-advice.

On Sun, Nov 17, 2013 at 7:51 PM, Robert J. Hijmans <r.hijmans at gmail.com> wrote:
> I think it was possible; the 'crs' argument is passed on by the
> ellipsis; but only if the file had an unknown crs (it is in the help
> file under Details).
>
> I think it broke because of a change in sp (or rgdal). Previously, if
> the crs was unknown, the CRS object would store "NA" (with quotes),
> now it has NA (no quotes). That seems to be an improvement but broke
> the raster code. This has been fixed for the next version of raster.
>
> Robert
>
> On Sun, Nov 17, 2013 at 8:27 AM, Michael Sumner <mdsumner at gmail.com> wrote:
>> I don't think it ever was possible to do this. If you look carefully
>> at the Details for ?raster, it mentions extra arguments passed via ...
>> and none of these is "crs" for the "character" method. That can be a
>> bit obscure until you understand that the character method (for a
>> file) does not allow you to pass in crs at that point, it's only
>> defined for the signatures  "missing", "Extent", "matrix" and
>> "big.matrix".
>>
>> Does that make sense?
>>
>> On Fri, Nov 15, 2013 at 6:35 PM, Arnaud Mosnier <a.mosnier at gmail.com> wrote:
>>> Hi Jan,
>>>
>>> Thanks.
>>> You can also use
>>> proj4string(r) <- "+proj=longlat +ellps=WGS84"
>>>
>>> but the problem (the bug ?) is that it does not work anymore defining
>>> directly the crs into the raster function.
>>>
>>> Arnaud
>>>
>>>
>>> 2013/11/15 Verbesselt, Jan <jan.verbesselt at wur.nl>
>>>
>>>> Hi Arnaud,
>>>>
>>>> Something like:
>>>>
>>>> r <- raster()
>>>> projection(r)
>>>> projection(r) <- "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100 +ellps=WGS84"
>>>> projection()
>>>>
>>>>
>>>> Might help,
>>>>
>>>> Best,
>>>> Jan
>>>>
>>>>
>>>> On 15/11/13 17:52, "Arnaud Mosnier" <a.mosnier at gmail.com> wrote:
>>>>
>>>> >Hi all,
>>>> >
>>>> >I re-run a script written some times ago containing a line like the
>>>> >following
>>>> >
>>>> >test <- raster("myraster.tif", crs = "+proj=longlat +ellps=WGS84")
>>>> >
>>>> >The file is loaded correctly, but the crs was not attributed.
>>>> >
>>>> >>proj4string(test)
>>>> >
>>>> >gives me
>>>> >
>>>> >[1] "NA"
>>>> >
>>>> >
>>>> >When looking at the help file, nothing seems to have changed, so what the
>>>> >problem ?
>>>> >Any suggestion ?
>>>> >
>>>> >Thanks
>>>> >
>>>> >Arnaud
>>>> >
>>>> >       [[alternative HTML version deleted]]
>>>> >
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>>>> >
>>>>
>>>>
>>>>
>>>
>>>         [[alternative HTML version deleted]]
>>>
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>>
>>
>>
>> --
>> Michael Sumner
>> Hobart, Australia
>> e-mail: mdsumner at gmail.com
>>
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-- 
Michael Sumner
Hobart, Australia
e-mail: mdsumner at gmail.com



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