Ahhh...a missing "+".  Probably caused by a lack of caffeine. :)
Thanks also for suggesting the raster package... I will look into this.

Julian

On Wed, Oct 20, 2010 at 6:56 AM, Roger Bivand <Roger.Bivand@nhh.no> wrote:

> On Wed, 20 Oct 2010, Julian Burgos wrote:
>
>  Dear list,
>> I have a problem trying to change the projection of a
>> SpatialPixelsDataFrame, from UTM to lat/long.  My object has the following
>> characteristics:
>>
>>  summary(mb)
>>>
>> Object of class SpatialPixelsDataFrame
>> Coordinates:
>>       min       max
>> X -14.17196 -13.76879
>> Y  63.75071  63.96791
>> Is projected: TRUE
>> proj4string : [+proj=utm +zone=28 +datum=WGS84]
>> Number of points: 5669540
>> Grid attributes:
>>  cellcentre.offset     cellsize cells.dim
>> X         -14.17189 1.347473e-04      2992
>> Y          63.75074 5.944386e-05      3654
>> Data attributes:
>>  Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
>>  108.5   230.3   256.9   283.0   287.9   987.6
>>
>> when using the  spTransform I get the following error message:
>>
>>  mb=spTransform(mb,CRS("proj=longlat +datum=WGS84"))
>>>
>> Error in spTransform(mb, CRS("proj=longlat +datum=WGS84")) :
>>  error in evaluating the argument 'CRSobj' in selecting a method for
>> function 'spTransform'
>>
>
> The error was caused by a missing +:
>
> library(rgdal)
> data(meuse.grid)
> gridded(meuse.grid) <- TRUE
> proj4string(meuse.grid) <- CRS("+init=epsg:28992")
> ll <- spTransform(meuse.grid, CRS("proj=longlat +datum=WGS84"))
> ll <- spTransform(meuse.grid, CRS("+proj=longlat +datum=WGS84"))
>
> which coerces to points first, as Mike said it should.
>
> Roger
>
>
>> Any ideas what is the problem?
>> Many thanks,
>>
>> Julian Burgos
>>
>> Julian Mariano Burgos
>> Hafranns?knastofnunin/Marine Research Institute
>> Sk?lagata 4, 121 Reykjav?k, Iceland
>> S?mi/Telephone : +354-5752037
>> Br?fs?mi/Telefax:  +354-5752001
>>
>> Netfang/Email: julian@hafro.is, jmburgos@uw.edu
>>
>>        [[alternative HTML version deleted]]
>>
>>
>>
> --
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand@nhh.no
>
>


-- 
Julian Mariano Burgos
Hafrannsóknastofnunin/Marine Research Institute
Skúlagata 4, 121 Reykjavík, Iceland
Sími/Telephone : +354-5752037
Bréfsími/Telefax:  +354-5752001
Netfang/Email: julian@hafro.is, jmburgos@uw.edu

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