Hi, I have a vectors x and z, for example, x <- 0:20 z <- round(runif(20,1,7)) y <- 0.5 and I want to display z as an image. However if I then call image() with a vector image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") then I get the error Error in image.default(x, y, t(z), zlim = c(1, 7), col = heat.colors(7), : dimensions of z are not length(x)(-1) times length(y)(-1) However, transforming z into a matrix with two rows, where both rows are the same as z above does seem to be a workaround. z <- matrix(c(z,z),2,length(z),byrow=TRUE) y <- c(0.25,0.75) image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") The problem is that when I include the figure that is produced in my pdf, there ends up being a white line that runs through the middle horizontally (where the divison of the cells is) which ruins the presentation of the graphic as x is a time series, and z is an action that is performed at that time. There is only one action that is performed at each time step in x, and having the line running through the middle might cause confusion as to how many actions are performed at any given time. I would appreciate any suggestions as to how to get around this, because I haven't been able to find any options for vectors in image(), or if there is a different function that does it. Cheers Steven
On Tue, Feb 15, 2011 at 8:43 PM, Steven Cordwell <s.cordwell at uq.edu.au> wrote:> Hi, > > I have a vectors x and z, for example, > > x <- 0:20 > z <- round(runif(20,1,7)) > y <- 0.5 > > and I want to display z as an image. However if I then call image() with a vector > > image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r")try image(x,y,as.matrix(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") as.matrix(vector) converts the vector into a 1-column matrix, which seems to be what you need. Peter
Steven Cordwell wrote:> > However, transforming z into a matrix with two rows, where both rows are > the same as z above does seem to be a workaround. > > z <- matrix(c(z,z),2,length(z),byrow=TRUE) > y <- c(0.25,0.75) > image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") > > The problem is that when I include the figure that is produced in my pdf, > there ends up being a white line that runs through the middle horizontally > (where the divison of the cells is) which ruins the presentation ofThis looks more like a problem of pdf than one of image. Under Windows and current R, I cannot reproduce the line in the pdf, but we have seen this before. If you are sure that you have the current version of R installed, you could send in a bug report, but make sure sessionInfo() is included. One workaround that worked for me in the past to use a CairoPDF as show below. Dieter library(Cairo) CairoPDF(file="c:/tmp/Hello.pdf") x <- 0:20 y <- 0.5 z <- round(runif(21,1,7)) z <- matrix(c(z,z),2,length(z),byrow=TRUE) y <- c(0.25,0.75) image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action", yaxt="n",xaxs="r",yaxs="r") dev.off() -- View this message in context: http://r.789695.n4.nabble.com/image-with-a-vector-tp3308265p3308283.html Sent from the R help mailing list archive at Nabble.com.
Hi, rasterImage may alleviate the pdf artefacts in the viewer. This seems to produce a similar output, plot(range(x),range(y), t="n") rasterImage(t(rgb(colorRamp(heat.colors(7))(z/max(z))/255)), min(x),min(y),max(x),max(y), interpolate=FALSE) HTH, baptiste On 16 February 2011 05:43, Steven Cordwell <s.cordwell at uq.edu.au> wrote:> Hi, > > I have a vectors x and z, for example, > > x <- 0:20 > z <- round(runif(20,1,7)) > y <- 0.5 > > and I want to display z as an image. However if I then call image() with a vector > > image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") > > then I get the error > > Error in image.default(x, y, t(z), zlim = c(1, 7), col = heat.colors(7), ?: > ?dimensions of z are not length(x)(-1) times length(y)(-1) > > However, transforming z into a matrix with two rows, where both rows are the same as z above does seem to be a workaround. > > z <- matrix(c(z,z),2,length(z),byrow=TRUE) > y <- c(0.25,0.75) > image(x,y,t(z),zlim=c(1,7),col=heat.colors(7),xlab="Year",ylab="Action",yaxt="n",xaxs="r",yaxs="r") > > The problem is that when I include the figure that is produced in my pdf, there ends up being a white line that runs through the middle horizontally (where the divison of the cells is) which ruins the presentation of the graphic as x > is a time series, and z is an action that is performed at that time. There is only one action that is performed at each time step in x, and having the line running through the middle might cause confusion as to how many actions are > performed at any given time. > > I would appreciate any suggestions as to how to get around this, because I haven't been able to find any options for vectors in image(), or if there is a different function that does it. > > Cheers > > Steven > > ______________________________________________ > R-help at 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 > and provide commented, minimal, self-contained, reproducible code. >