[R-sig-Geo] different projection transformation R and gdal commandline

[Dominik Schneider]

Hi,
I'm struggling to use a custom projection. I am seeing differences with
someone using python proj4 bindings and when I compared my R results with
my commandline results I got even more confused. the coordinate
transformation is different for the two different methods.

could someone explain to me which one is wrong and why?
Thanks

R:
e=c(-112.25,-104.125,33,43.75)
box=as(extent(e),'SpatialPolygons')
proj4string(box)='+proj=longlat +datum=WGS84'
pstring='+proj=lcc +lat_1=28 +lat_2=50 +lat_0=39.70001220694445 +lon_0=-98
+x_0=0 +y_0=0 +ellps=sphere +a=6370000 +b=6370000 +units=m +no_defs'
xmin(spTransform(box,CRS(pstring)))
## [1] -1306471
ymin(spTransform(box,CRS(pstring)))
## [1] -713442.3

commandline:
iMac:~ $ gdaltransform -s_srs "+proj=longlat +datum=WGS84" -t_srs
"+proj=lcc +lat_1=28 +lat_2=50 +lat_0=39.70001220694445 +lon_0=-98 +x_0=0
+y_0
=0  +ellps=sphere  +a=6370000 +b=6370000 +units=m +no_defs"
-112.25 33.
-1306675.75472246 -629522.472322824 0

	[[alternative HTML version deleted]]