[Proj] problem in trunk/4.9.0 in R/rgdal

[Roger Bivand]

On Thu, 6 Feb 2014, Roger Bivand wrote:

> We see a problem in 4.9.0 that is not in 4.8.0 in R. The code provoking the 
> problem in rgdal 0.8-15 built against 4.9.0 (trunk):
>
> http://cran.r-project.org/src/contrib/rgdal_0.8-15.tar.gz

A simpler example is:

minimal install is install.packages(c("sp", "rgdal"))

library(rgdal)
checkCRSArgs("+init=epsg:4326 +proj=longlat +ellps=WGS84 +datum=WGS84 
+no_defs +towgs84=0,0,0")

failing with:

> library(rgdal)
Loading required package: sp
rgdal: version: 0.8-15, (SVN revision 496M)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 1.11dev, released 2013/04/13
Path to GDAL shared files: /usr/local/share/gdal
Loaded PROJ.4 runtime: Rel. 4.9.0, 27 October 2013, [PJ_VERSION: 490]
Path to PROJ.4 shared files: (autodetected)
> checkCRSArgs("+init=epsg:4326 +proj=longlat +ellps=WGS84 +datum=WGS84 
+no_defs +towgs84=0,0,0")
[[1]]
[1] FALSE

[[2]]
[1] "no options found in 'init' file"

Roger

>
> minimal install is install.packages(c("sp", "spacetime", "rgdal"))
>
> library(sp)
> library(spacetime)
> data(air)
> library(rgdal)
> checkCRSArgs(proj4string(rural at sp))
>
> which shows:
>
>> checkCRSArgs(proj4string(rural at sp))
> [[1]]
> [1] FALSE
>
> [[2]]
> [1] "no options found in 'init' file"
>
> first time round. The object rural is read in from a saved R object, and has 
> a stored projection of:
>
> "+init=epsg:4326 +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs 
> +towgs84=0,0,0"
>
> So when this string goes via checkCRSArgs() to C code (same function name) 
> calling:
>
>
> if (!(pj = pj_init_plus(CHAR(STRING_ELT(args, 0))))) {
> 	SET_STRING_ELT(VECTOR_ELT(res, 1), 0,
>        COPY_TO_USER_STRING(pj_strerrno(*pj_get_errno_ref())));
> 	UNPROTECT(1);
> 	return(res);
> }
>
> where res is a list with first element FALSE by default, second contains an 
> error message on failure (or what pj_get_def() returns on success. This 
> around line 292 in:
>
> https://r-forge.r-project.org/scm/viewvc.php/pkg/src/projectit.cpp?view=markup&root=rgdal
>
> However, if we then do:
>
> checkCRSArgs("+init=epsg:4326")
>
> we tickle something in pj_init_plus() and it works, and subsequently:
>
> checkCRSArgs(proj4string(rural at sp))
>
> works. I cannot see any changes in pj_init.c in the section looking for +init 
> between 4.8.0 and 4.9.0 that might affect this. Under rgdal 0.8-15 and 4.8.0, 
> there is no trouble, but the issue arises predictably with the same rgdal 
> 0.8-15 and current 4.9.0 trunk.
>
> I'd be grateful for any advice.
>
> Best wishes,
>
> Roger
>
>

-- 
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 95 43
e-mail: Roger.Bivand at nhh.no