[R-sig-Geo] execGRASS and v.mkgrid gives "Parameter <coor> does not have float value"

[Lars Dalby]

Hi 

I have tried to post this via Nabble, but apparently that did not work. So I try here again. I apologise in case this leads to double posting.

I have been trying to expand a vector grid using the v.mkgrid command in GRASS via the execGRASS function in spgrass6. I have passed several other commands via execGRASS and it has worked perfectly. However when using the v.mkgrid function I get an error. 

I work in a location with a Behrman projection which is a cylindrical equal area projection with units in meters. 

I call: 
execGRASS('v.mkgrid', parameters = list(map = 'VectorGrid', position = 'coor', coor = '-6358820,-17367529', grid = '142,360', box = '96486.28169014, 96486.28055556')) 

and get this error message: 
Error in doGRASS(cmd, flags = flags, ..., parameters = parameters, echoCmd = echoCmd) : 
  Parameter <coor> does not have float value 

With great help from Micha at the GRASS-user list we tried to figure this out and found an old bug report, that seems to be somewhat related: http://trac.osgeo.org/grass/ticket/739
However the workaround suggested here does not really do the trick. 

The thread I started on the GRASS-user list is here: http://osgeo-org.1560.n6.nabble.com/Rasterize-polygons-multiple-polygons-per-grid-cell-td5005264.html

A reproducible example and my session info is below. 
Any hints to a workaround to this problem would be highly appreciated. 

Thanks 
-Lars 

require(spgrass6) 
# Replace the path with the path to the GRASS binaries on your system 
loc <- initGRASS('/Applications/GRASS/GRASS-7.0.app/Contents/MacOS', home=tempdir(), override = TRUE) 
execGRASS('v.mkgrid', parameters = list(map = 'VectorGrid', position = 'coor', coor = '-6358820,-17367529', grid = '142,360', box = '96486.28169014, 96486.28055556')) 
# Error in doGRASS(cmd, flags = flags, ..., parameters = parameters, echoCmd = echoCmd) : 
#   Parameter <coor> does not have float value 
unlink_.gislock() 

# sessionInfo(): 
#   R version 2.15.1 (2012-06-22) 
# Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit) 
# 
# locale: 
# [1] C/en_US.UTF-8/C/C/C/C 
# 
# attached base packages: 
# [1] stats     graphics  grDevices utils     datasets  methods   
# [7] base     
# 
# other attached packages: 
# [1] raster_2.0-12   spgrass6_0.7-10 XML_3.9-4       
# [4] sp_0.9-99       
# 
# loaded via a namespace (and not attached): 
# [1] grid_2.15.1     lattice_0.20-10 tools_2.15.1  



Lars Dalby, Msc., PhD student
E: lada at dmu.dk | T: +45 871 59013
Department of Bioscience, Aarhus University
Grenåvej 14, 8410 Rønde, Denmark