Dear Simon,
I understand better now and it is running.
//Belay
On Sat, May 19, 2012 at 1:22 PM, Simon Knapp <sleepingw...@gmail.com> wrote:
> I'm not sure what line you mean. The thing you pass to raster should
> be a matrix of the dimensions of your image data.
>
> You should have have xmin, xmax, ymin and ymax defined as something like:
>
> xmin <- min(x) - cw/2
> xmax <- max(x) + cw/2
> ymin <- min(y) - cw/2
> ymax <- max(y) + cw/2
>
> presuming that your x and y correspond to cell centres and where cw is
> your cell width (and if it is different in the two directions then you
> would 'cw.x' and 'cw.y'... if you know what I mean).
>
> Cheers,
> Simon
>
>
> On Sat, May 19, 2012 at 9:42 PM, Belay Gebregiorgis <belay...@gmail.com>
> wrote:
> > Thanks Simon. I have other vectors in the CSV file so after naming my
> > latitude and longitude x and y, I tried this. The first two lines run
> fine
> > but I get error in the second line.
> >
> >
> > r <- raster(as.matrix(F1))
> > extent(r) <- extent(xmin, xmax, ymin, ymax)
> > F1<-data.frame(x, y,z)
> >
> > Error in function (classes, fdef, mtable) :
> > unable to find an inherited method for function "extent", for signature
> > "stand
> > Thankyou.
> >
> > Belay
> > On Sat, May 19, 2012 at 12:22 PM, Simon Knapp <sleepingw...@gmail.com>
> > wrote:
> >>
> >> provided you get the call to read.table (or perhaps read.csv) right
> >> and presuming that file contains only the image data, you should
> >> be able to say:
> >>
> >> r <- raster(as.matrix(read.csv("file.csv")))
> >> extent(r) <- extent(xmin, xmax, ymin, ymax)
> >>
> >> and not worry about the projection (if it is plain old decimal degrees)
> >>
> >> Regards,
> >> Simon
> >>
> >> On Sat, May 19, 2012 at 7:49 PM, Belay Gebregiorgis <belay...@gmail.com
> >
> >> wrote:
> >> > Hello everyone,
> >> >
> >> > I want to get a 1km by lkm grid raster image using my csv data. If I
> >> > call
> >> > latitude=a, longitude=b and preciptation=c.
> >> >
> >> > a<-(1,2,3,4,5)
> >> > b<-(6,7,8,9,10)
> >> > c<-(10,20, 30,40, 50)
> >> >
> >> > Then I found an example in r help which goes like
> >> >
> >> > pts = read.table("file.csv",......)
> >> > library(sp)
> >> > library(rgdal)
> >> >
> >> > proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
> >> > pts = spTransform(pts,CRS("insert your proj4 string here"))
> >> > gridded(pts) = TRUE
> >> > r = raster(pts)
> >> > projection(r) = CRS("insert your proj4 string here")
> >> >
> >> > Because I am new to R, I have no idea what to put into the proj4
> string
> >> > and
> >> > all that. Can anyone help me on this? If there is a different way of
> >> > doing
> >> > this, that is also fine.
> >> >
> >> > Kind Regards,
> >> >
> >> > Belay
> >> >
> >> > [[alternative HTML version deleted]]
> >> >
> >> > ______________________________________________
> >> > R-help@r-project.org mailing list
> >> > https://stat.ethz.ch/mailman/listinfo/r-help
> >> > PLEASE do read the posting guide
> >> > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> >> > and provide commented, minimal, self-contained, reproducible code.
> >
> >
>
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