Hi all,
I'm new to R (and SAGA) and hope you can help resolve a problem which is
perplexing me. As part of my project i would like to use the
ta_morphometry module in the RSAGA library to calculate curvatures for a
DEM. I've cut back my code to the basics below: read the DEM, write this
into a SAGA format (I think I need to do this to make use of the SAGA
functions), call the RSAGA function which outputs the data in SAGA
format and finally read that data file (curve.sdat) into a raster
object. It seems to work (no errors thrown), but when I try to do
anything with the curve raster (including just plot it) I get the error
message "Error in endrow - nrow : non-numeric argument to binary operator".
This all works fine within the SAGA GUI, including plotting the curve
data, but I still cant read the output data file into R using raster.
Instead I have to export from SAGA as another format (eg Surfer) in
order to be able to read the data into a raster object. However I'd like
to be able to script the process without resorting to using the GUI to
change the file format.
Many thanks for your advice,
Andy Wilson
library (rgdal)
library (RSAGA)
library(raster)
r_elev <- raster("C:/Dissertation/DEMs/DEM.IMG")
#set environment for SAGA
myenv <- rsaga.env(workspace="C:/Dissertation/SAGA")
#output the DEM raster into a SAGA readable format
writeRaster(r_elev, filename="C:/Dissertation/SAGA/elev.sgrd",
format="SAGA", overwrite=TRUE)
# call the module function using geoprocessor
rsaga.geoprocessor("ta_morphometry", 0,
list(ELEVATION="elev.sgrd",SLOPE="slope",ASPECT="aspect",
CURV="curve",METHOD=5),env=myenv)
#create a raster from the curve data file
r_curve <- raster("C:/Dissertation/SAGA/curve.sgrd")
#plot the curve data
plot(r_curve)
R, raster & SAGA
3 messages · Andy Wilson, Robert J. Hijmans, Rainer Hurling
Andy, I think I fixed this in raster 1.7-11. Should be available from R-Forge in 24 hrs. It would be helpful if you could send me the file. Robert
On Wed, Dec 8, 2010 at 10:55 AM, Andy Wilson <andy.a.wilson at gmail.com> wrote:
Hi all,
I'm new to R (and SAGA) and hope you can help resolve a problem which is
perplexing me. As part of my project i would like to use the ta_morphometry
module in the RSAGA library to calculate curvatures for a DEM. I've cut back
my code to the basics below: read the DEM, write this into a SAGA format (I
think I need to do this to make use of the SAGA functions), call the RSAGA
function which outputs the data in SAGA format and finally read that data
file (curve.sdat) into a raster object. It seems to work (no errors thrown),
but when I try to do anything with the curve raster (including just plot it)
I get the error message "Error in endrow - nrow : non-numeric argument to
binary operator".
This all works fine within the SAGA GUI, including plotting the curve data,
but I still cant read the output data file into R using raster. Instead I
have to export from SAGA as another format (eg Surfer) in order to be able
to read the data into a raster object. However I'd like to be able to script
the process without resorting to using the GUI to change the file format.
Many thanks for your advice,
Andy Wilson
library (rgdal)
library (RSAGA)
library(raster)
r_elev <- raster("C:/Dissertation/DEMs/DEM.IMG")
#set environment for SAGA
myenv <- rsaga.env(workspace="C:/Dissertation/SAGA")
#output the DEM raster into a SAGA readable format
writeRaster(r_elev, filename="C:/Dissertation/SAGA/elev.sgrd",
format="SAGA", overwrite=TRUE)
# call the module function using geoprocessor
rsaga.geoprocessor("ta_morphometry", 0,
list(ELEVATION="elev.sgrd",SLOPE="slope",ASPECT="aspect",
CURV="curve",METHOD=5),env=myenv)
#create a raster from the curve data file
r_curve <- raster("C:/Dissertation/SAGA/curve.sgrd")
#plot the curve data
plot(r_curve)
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
On 08.12.2010 19:55 (UTC+1), Andy Wilson wrote:
Hi all,
I'm new to R (and SAGA) and hope you can help resolve a problem which is
perplexing me. As part of my project i would like to use the
ta_morphometry module in the RSAGA library to calculate curvatures for a
DEM. I've cut back my code to the basics below: read the DEM, write this
into a SAGA format (I think I need to do this to make use of the SAGA
functions), call the RSAGA function which outputs the data in SAGA
format and finally read that data file (curve.sdat) into a raster
object. It seems to work (no errors thrown), but when I try to do
anything with the curve raster (including just plot it) I get the error
message "Error in endrow - nrow : non-numeric argument to binary operator".
This all works fine within the SAGA GUI, including plotting the curve
data, but I still cant read the output data file into R using raster.
Instead I have to export from SAGA as another format (eg Surfer) in
order to be able to read the data into a raster object. However I'd like
to be able to script the process without resorting to using the GUI to
change the file format.
Many thanks for your advice,
Andy Wilson
library (rgdal)
library (RSAGA)
library(raster)
r_elev <- raster("C:/Dissertation/DEMs/DEM.IMG")
#set environment for SAGA
myenv <- rsaga.env(workspace="C:/Dissertation/SAGA")
#output the DEM raster into a SAGA readable format
writeRaster(r_elev, filename="C:/Dissertation/SAGA/elev.sgrd",
format="SAGA", overwrite=TRUE)
# call the module function using geoprocessor
rsaga.geoprocessor("ta_morphometry", 0,
list(ELEVATION="elev.sgrd",SLOPE="slope",ASPECT="aspect",
CURV="curve",METHOD=5),env=myenv)
#create a raster from the curve data file
r_curve <- raster("C:/Dissertation/SAGA/curve.sgrd")
As a workaround until raster 1.7-11 is available the following step
should work (note that you have to use '.sdat' instead of '.sgrd' with
rgdal):
r_curve <- raster(readGDAL("C:/Dissertation/SAGA/curve.sdat"))
Hope this helps,
Rainer Hurling
#plot the curve data plot(r_curve)