Hi,
I'm running R 2.11.0 on a 32 bit Windows Vista machine. I have new versions of
all relevant libraries installed. I have been reading from IDRISI .rst files
and this works fine using raster() and getValues(). I have passed the values
from the .rst files through another R object and would like to write them as an
.rst file. In the following code, I am attempting to set the 1st row values of
a RasterLayer object and then write these to a .rst file. All raster files I
am working with have 3,700 columns and 4,203 rows and are Connecticut
StatePlane coordinate system which is equivalent to lambert's conformal conic
proj.
#extract 2nd column of a matrix which are the values of interest for the 1st row
p1a<-p1[c(1:3700),c(2)]
p1am<-as.matrix(p1a)
#create RasterLayer object from a .rst file that was created in IDRISI
beforehand with all 0s (real nums) for cell values
put<-raster("C:\\rforest\\data\\rst85\\write2.rst",values=FALSE)
#set 1st row to equal the values of interest
put<-setValues(put,p1am,1)
#write to a .rst file that I created in IDRISI beforehand with all 0s (real
nums)
writeRaster(put, filename="C:\\rforest\\data\\rst85\\write5.rst",
format="IDRISI",overwrite=TRUE)
PROBLEM:
Until the writeRaster function call, everything is working. I can use
getValues to look at the 1st row of "put", and this equals p1am values. I can
look at the 2nd row of "put" and they are all zeros. The writeRaster function
does not give an error but, when opened in IDRISI, the legend seems correct but
the values are expressed in scientific notation and are MUCH too small. Also,
the 1st row values are copied for all rows, when I expect all but row=1 to be
equal to 0. I tried, prior to opening in IDRISI, to create a RasterLayer
object from the output raster from writeRaster above, to see if R gives the
result wanted. This results in the following error message and report on the
RasterLayer object created.
> put2<-raster("C:\\rforest\\data\\rst85\\write5.rst",values=TRUE)
> put3<-getValues(put2,1)
Error:
GDAL Error 3: Can't read(C:\rforest\data\rst85\write5.rst) block with X
offset 0 and Y offset 0.
No error
Error in values(readRows(x, row, nrows)) :
error in evaluating the argument 'x' in selecting a method for function
'values'
> put2
class : RasterLayer
filename : C:\rforest\data\rst85\write5.rst
nrow : 4203
ncol : 3700
ncell : 15551100
min value : 0
max value : 0
projection : +proj=lcc +lat_1=41.86666666666667 +lat_2=41.2
+lat_0=40.83333333333334 +lon_0=-72.75 +x_0=304800.6096 +y_0=152400.3048
+ellps=GRS80 +datum=NAD83 +units=m +no_defs +towgs84=0,0,0
xmin : 221895.5
xmax : 334671.7
ymin : 164342.4
ymax : 292450.1
xres : 30.48006
yres : 30.48006
I have tried this entire process starting NOT with blank 0 rasters to create my
SpatialLayer object (a shortcut I thought may be a problem) but instead
creating rasters by specifying projections etc on non-used filenames. The
results are the same.
Thanks,
Seth
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