Dear Jonathan,

First of all, congratulations on the package. It installed without a glitch in all of my platforms: Mac, Windows and Linux. 

However, I have a question on the speed of the wrapper functions.

In the past sometimes I caught myself using GDAL instead of R for some routines when dealing with really large datasets (1GB+ shapefiles and 2GB+ rasters). Most of the routines were resampling and reprojection. 

While R used to run for several hours, GDAL binaries finished the task in a matter of seconds.

Unfortunately I don't have access to those previous large datasets to perform some tests with the package, and this is why I ask you: do you think that gdalUtils functions are as fast as the GDAL binaries?

Many thanks in advance. Congratulations once again for the very useful package!
 
Greetings,
--
Thiago V. dos Santos
PhD student
Land and Atmospheric Science
University of Minnesota
http://www.laas.umn.edu/CurrentStudents/MeettheStudents/ThiagodosSantos/index.htm
Phone: (612) 323 9898



On Wednesday, January 8, 2014 4:43 PM, Jonathan Greenberg <jgrn@illinois.edu> wrote:
 
I would like to announce a new R package "gdalUtils", now on CRAN.
gdalUtils is a set of R wrappers for most of the GDAL utility programs
(http://gdal.org/gdal_utilities.html).  gdalUtils is a collaboration
between Matteo Mattiuzzi and me.

gdalUtils requires an already-installed GDAL on your system:
http://trac.osgeo.org/gdal/wiki/DownloadingGdalBinaries

For Windows, I recommend installing QGIS Standalone
(http://www.qgis.org/en/site/forusers/download.html) which appears to
have the most up-to-date binaries of GDAL for the Windows operating
system including support for HDF4/5 files.

Note that this is NOT a replacement for Roger Bivand's fantastic rgdal
package, it is a complementary package that simply provides R-wrappers
for functions like gdalwarp, gdal_translate, ogr2ogr, etc.  We've
tried to make the interface more R-like in terms of input parameters,
and have provided some additional features such as (when relevant)
returning outputs in Robert Hijman's raster format.  The parameter
naming and the documentation follows GDAL, with permission from Frank
Warmerdam (lead GDAL developer).

We have also provided some value-added functions such as
batch_gdal_translate and get_subdatasets (for extracting subdataset
names from HDF4/5 and NetCDF files).

I will note the primary motivation for developing this package was
initially to provide (finally) HDF4/5 file support to Windows users
(for Landsat and MODIS processing, among other things).  However, many
of the GDAL functions provide additional capabilities that R functions
do not currently have, and they are quite a bit faster than most of
their R equivalents (compare projectRaster_rigorous in my
spatial.tools package to gdalwarp(...,method="mode") for an example).

When you first fire it up, it may take a bit to search for a valid
GDAL install on your computer.  If you have more than one (Windows
users may find this), it will use the latest version.  We tried to
make this system-agnostic, but let us know if you have any problems
getting the functions to work.  The best way to test is:
library(gdalUtils)
gdalinfo(version=TRUE)
gdalinfo(formats=TRUE)

Cheers!

--j

-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
259 Computing Applications Building, MC-150
605 East Springfield Avenue
Champaign, IL  61820-6371
Phone: 217-300-1924
http://www.geog.illinois.edu/~jgrn/
AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307, Skype: jgrn3007

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