R help - Aug 2009 - image plot

Hi,
I am trying to use the image function to do a color plot. My matrix columns
are labeled y and x. I tried >image(y, x) but I had error message
("Error in
image.default(y, x) : increasing 'x' and 'y' values
expected").
Could anybody please tell me how to add these increasing 'x' and
'y' values.
Thanks

	[[alternative HTML version deleted]]

ogbos okike schreef:
> Hi,
> I am trying to use the image function to do a color plot. My matrix columns
> are labeled y and x. I tried >image(y, x) but I had error message
("Error in
> image.default(y, x) : increasing 'x' and 'y' values
expected").
> Could anybody please tell me how to add these increasing 'x' and
'y' values.
> Thanks
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>   
Hi,

Please provide a reproducible example.

An example that works with image:

x = 1:10
y = seq(1,100,by =10)
z = matrix(runif(100), 10, 10)
image(x,y,z)
x = sort(runif(10))
y = sort(runif(10))
image(x,y,z)

So z is a matrix with the values and x and y tell the dimensions of each 
cell, often with equal interval.

cheers,
Paul

ogbos okike wrote:
> Hi,
> I am trying to use the image function to do a color plot. My matrix columns
> are labeled y and x. I tried >image(y, x) but I had error message
("Error in
> image.default(y, x) : increasing 'x' and 'y' values
expected").
> Could anybody please tell me how to add these increasing 'x' and
'y' values.
>   
Hi Ogbos,
I think you may be passing the values that you want displayed rather 
than the positions of those values on a 2D grid. Try sending your matrix 
to color2D.matplot in the plotrix package. That just converts the values 
into colors and may be more like what you want.

Jim