You could try the focalFilter function in the raster package:
install.packages("raster", repos="http://R-Forge.R-project.org";)
with this argument for the Sobel filter:
filter=matrix(c(1,2,1,0,0,0,-1,-2,-1) / 4, nrow=3)
(For using raster this way you should upgrade to R 2.9 first, if you
have not
I'm looking to calculate gradients from oceanographic variables (ie. sea
surface temperature, chlorophyll, etc.) for which I have downloaded in ESRI
grid format (.asc). From some research on gradient analysis, I have found a
few people who have used a Sobel filter to estimate gradients in images (
On Tue, 5 May 2009, Roger Bivand wrote:
On Tue, 5 May 2009, Agustin Lobo wrote:
Roger,
After upgrading, the test works with plugin=F,
while plugin=T produces the same result.
I find this too on Fedora 10, plugin=TRUE fails after a hundred or so calls,
and then crashes R on a further comma
On Tue, 5 May 2009, Agustin Lobo wrote:
Roger,
After upgrading, the test works with plugin=F,
while plugin=T produces the same result.
I find this too on Fedora 10, plugin=TRUE fails after a hundred or so
calls, and then crashes R on a further command. With plugin=FALSE, there
is no proble
Roger,
After upgrading, the test works with plugin=F,
while plugin=T produces the same result.
Also, ignore.stderr=T yields:
ERROR 6: SetColorTable() only supported for Byte or UInt16 bands in TIFF
format.
WARNING: Input raster map constains cells with NULL-value (no-data). The
value
On Tue, 5 May 2009, Alina Sheyman wrote:
and for some reason I am still getting the error that I have non-unique id's
eventhough i had deduped both of my files. Any idea why this would be
happening?
Please refer to comments below:
On Tue, May 5, 2009 at 10:16 AM, Alina Sheyman wrote:
I'
and for some reason I am still getting the error that I have non-unique id's
eventhough i had deduped both of my files. Any idea why this would be
happening?
On Tue, May 5, 2009 at 10:16 AM, Alina Sheyman wrote:
>
> I'm still working on trying to combine two spatial files.
> So far I've done the
On Tue, 5 May 2009, Agustin Lobo wrote:
Here it is:
R version 2.9.0 (2009-04-17)
i486-pc-linux-gnu
locale:
LC_CTYPE=es_ES.UTF-8;LC_NUMERIC=C;LC_TIME=es_ES.UTF-8;LC_COLLATE=es_ES.UTF-8;LC_MONETARY=C;LC_MESSAGES=es_ES.UTF-8;LC_PAPER=es_ES.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMEN
Here it is:
R version 2.9.0 (2009-04-17)
i486-pc-linux-gnu
locale:
LC_CTYPE=es_ES.UTF-8;LC_NUMERIC=C;LC_TIME=es_ES.UTF-8;LC_COLLATE=es_ES.UTF-8;LC_MONETARY=C;LC_MESSAGES=es_ES.UTF-8;LC_PAPER=es_ES.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=es_ES.UTF-8;LC_IDENTIFICATION=C
attache
I'm still working on trying to combine two spatial files.
So far I've done the following
zipmaps1a<- unionSpatialPolygons(zipmaps1,IDs=paste(zipmaps1$ZCTA))
zipmaps1_df<- as(zipmaps1, "data.frame") [!duplicated(zipmaps1$ZCTA),
-(1:4)]
row.names(zipmaps1_df)<- paste(zipmaps1_df$ZCTA)
zipmaps1b <- S
On Tue, 5 May 2009, Agustin Lobo wrote:
We're using
rastdum <- readRAST6("nomdum",cat=F,ignore.stderr = T)
(on a ubuntu 8.10 machine and R 2.9)
within a for() loop of hundreds of iterations.
At some point (ca. 199) we get an error
"Too many open files"
and suspect that this is because readRAS
We're using
rastdum <- readRAST6("nomdum",cat=F,ignore.stderr = T)
(on a ubuntu 8.10 machine and R 2.9)
within a for() loop of hundreds of iterations.
At some point (ca. 199) we get an error
"Too many open files"
and suspect that this is because readRAST6() is opening
and not closing files. Is
On Tue, 5 May 2009, Agustin Lobo wrote:
I have a complex shape file imported to R via rgdal
as a SPolDF. I want to display continuous attributes
with a color key but the black boundaries
of the polygons, which are small in general, introduce
"too much black" in the plot and the spatial variation
I have a complex shape file imported to R via rgdal
as a SPolDF. I want to display continuous attributes
with a color key but the black boundaries
of the polygons, which are small in general, introduce
"too much black" in the plot and the spatial variation
of the attribute is not correctly display
Dear list,
I would like to calculate an index of eccentricity (ECC) of an animal's
home range (a polygon determined with adehabitat package and then
exported as shapefile). ECC=l/w, where 'l' is the maximum lenght of the
polygon, and 'w' is the maximum width of the polygon. Could you
suggestm
On Mon, 4 May 2009, dominik baenninger wrote:
Dear list,
When plotting spatial informaion it is common to use a pixel map as
background. Therefore I used the following commands (in brief)
library(sp)
library(rgdal)
pdf()
readGDAL(geotiff-file)
image()
plot(...,add=T)
dev.off()
This works f
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