Oh, silly me. doing plot(spTransform(box,CRS(pstring))) and it's obvious
what's happening. The projection rotates the polygon such that for the
corners y1,x1 and y2,x2 y1 != y2. But ymin(spTransform(box,CRS(pstring)))
still gives you the smallest coordinate regardless of which corner it is.
Hi Chris,
Thanks for confirming this. I'm not surprised that gdalUtils gives the same
answer as the gdal utilities - my understanding is that gdalUtils is
basically the equivalent to calling the commandline utilities via system().
I'm hoping that someone can shed light on spTransform since I use
Hi Dominik,
If you use the gdalUtils package there is no significant difference in
the results using CLI or R:
library(gdalUtils)
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
Sorry, forgot to add the details. rgdal and gdal 1.11.3 were installed from
kyngchaos.com
> sessionInfo()
R version 3.2.3 (2015-12-10)
Platform: x86_64-apple-darwin14.5.0 (64-bit)
Running under: OS X 10.11.3 (El Capitan)
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
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
