[R-sig-Geo] rgdal - problem with reading grib files

[Santiago Beguería Portugués]

Hi,

I am stuck when trying to read data from certain grib files with GDAL. When I try to read the data I get the following error:

> tmp <- readGDAL('./data/ghcn_cams/ghcn_cams_1948_cur.grb')
...
Error in `proj4string<-`(`*tmp*`, value = <S4 object of class "CRS">) : 
  Geographical CRS given to non-conformant data

I read on this mail list that this might be caused by data being outside the valid range for the CRS. And so it seems:

> GDALinfo('./data/ghcn_cams/ghcn_cams_1948_cur.grb')
rows        360 
columns     720 
bands       768 
origin.x        0.25 
origin.y        -90.25 
res.x       0.5 
res.y       0.5 
ysign       -1 
oblique.x   0 
oblique.y   0 
driver      GRIB 
projection  +proj=longlat +a=6371200 +b=6371200 +no_defs 
file        ./data/ghcn_cams/ghcn_cams_1948_cur.grb 

Since the origin.y coordinate is -90.25. However, according to the metadata provided in an accompanying file the lowest y coordinate should be -89.75:

dset ^ghcn_cams_1948_cur.grb
index ^ghcn_cams_1948_cur.grb.idx
undef 9.999E+20
title ghcn_cams_1948_cur.grb
*  produced by grib2ctl v0.9.12.5p39a
dtype grib 255
options yrev
ydef 360 linear -89.750000 0.5
xdef 720 linear 0.250000 0.500000
tdef 768 linear jan1948 1mo
zdef 1 linear 1 1
vars 1
TMP2m  0 11,105,2 ** 2 m above ground Temp. [K]
ENDVARS

I need to find a workaround to solve this problem, but I'm new to grib files (mostly used netCDF before) and I don't know how to proceed. Would appreciate any help.

Thank you in advance,


	Santiago Beguería