[R-sig-Geo] a minor bug in rgdal?

[epaiv01]

Dear Prof. Bivand,

Thank You very much for Your fast response. Now the proj4string after 
spTransform is ok.
Many thanks again.

Best regards,

Martin Ivanov

On 12/08/2012 08:39 PM, Roger Bivand wrote:
> On Sat, 8 Dec 2012, epaiv01 wrote:
>
>> Dear Prof. Bivand,
>>
>> I am running R-2.15.2 with rgdal version 0.7-22.
>> I noticed the following bug: when transforming a SpatialPoints object,
>> a white space is prepended to the proj4string of the target CRS. For 
>> example:
>
> Thanks for a helpful example. The problem has been around for a long 
> time, and is basically caused by pj_get_def() in PROJ.4, which 
> prepends a space. This function is called in various places in rgdal, 
> and in addition, when the sp constructor method for CRS objects is 
> called when rgdal is loaded, it is called then too; it checks the 
> string for formal errors. Probably a forthcoming release of sp would 
> have permitted this to be resolved at the R level, but in order to 
> sort things out for earlier sp versions, I've added a trap in the C 
> code in rgdal. I've committed the fix to R-forge SVN revision 402.
>
> Please let me know if this helps,
>
> Roger
>
>>
>> crds <- matrix(data=c(9.05, 48.52), ncol=2)
>> spPoint <- SpatialPoints(coords=crds,
>> proj4string=CRS("+proj=longlat +ellps=sphere +no_defs"))
>> a <- spTransform(spPoint, CRS(paste("+proj=ob_tran +o_proj=longlat",
>> "+o_lon_p=-162 +o_lat_p=39.25 +lon_0=180 +ellps=sphere +no_defs")),
>> use_ob_tran=TRUE)
>>
>> proj4string(a)
>> # " +proj=ob_tran +o_proj=longlat +o_lon_p=-162 +o_lat_p=39.25 
>> +lon_0=180 +ellps=sphere +no_defs"
>>
>> As You can see, a white space is prepended to the proj4string, from 
>> "+proj=ob_tran ..."
>> it becomes " +proj=ob_tran ...". This leads to errors when one 
>> interpolates using krige from gstat for example.
>>
>> Best regards,
>>
>>
>>
>


-- 
Dr. Martin Ivanov
Eberhard-Karls-Universität Tübingen
Mathematisch-Naturwissenschaftliche Fakultät
Fachbereich Geowissenschaften
Water & Earth System Science (WESS)
Hölderlinstraße 12, 72074 Tübingen, Deutschland
Tel. +4970712974213