[R-sig-Geo] combining two image files into one database

[Alok K. Bohara, PhD]

Thanks Greg for your response:

I want to do what the examples in Spatstat do with regard to the point  
and pixel/image data bei and bei.extra.. (bei.extra contains a list of 
two image files --elevation and gradient.  They plot these two items 
(and also take log, I believe)

In my case:

X_image 
Y_image

(I converted  both from text matrix to pixel/image using  "im(...)" command)

I want to combine (or list) X_image and Y.image as a part of a single 
file -- XY_image, and save and do the following

load("XY.image")

plot(XY_image)    # plot both images side by side
plot(XY_image$X_image)   # plot just the X_image
etc...

Thank you for your help.

#########

I tried doing the list command:
XY_image <-list(X_image,Y_image)

but it returns NULL when I do  "XY$X_image"

Sincerely,
Alok Bohara





Greg Lee wrote:
> Hello Alok,
>  
> We really need more details about what you are trying to acheive in 
> order to help you.
>  
> c(X, Y) concatenates the objects X and Y. The result will be a vector. 
> If X and Y happen to be m x n matrices, the result will be a vector of 
> length 2 * m * n: probably not what you want.
>  
> You can see this for yourself. Eg:
>  
> X <- matrix(1, 3, 3)
> Y <- matrix(2, 3, 3)
> c(X, Y)
>
> If you were hoping to combine the information in corresponding pixels 
> of the matrices X and Y, you will need to have a clear idea of *how* 
> you would like the information to be combined. ie: Are you looking for 
> the mean value of the pixels, or is some other operation required?
>  
> Eg 2:
>  
> X <- matrix(1:9, 3, 3)
> Y <- matrix(2, 3, 3)
> X + Y / 2 
>  
> Hope that helps. 
>  
> Greg 
>  
>  
> 2009/1/7 Alok K. Bohara, PhD <bohara at unm.edu <mailto:bohara at unm.edu>>
>
>     Hi:
>
>     Let me start by saying that I am new to R.  I converted two pixel
>     ascii matrices into image files:
>
>     X_im <- im(X)   # X is an ascii pixel matrix
>     Y_im <- im(Y)  # Y is an ascii pixel matrix
>
>     How can I combine these two images into 1) one datafile "XY_im",
>     2) save it  and 3) read it after loading (e.g., x <- XY_im$X_im.
>     and plot it.)
>
>     I tried doing this:
>
>     XY_im <- c(X_im,Y_im)
>     save(XY _im, file = "XM_im.Rdata")
>     load("XY_im.Rdata")
>     x<- XY_im$X_im    # It does not like $ and says it is atomic
>     something...
>     plot(x)  # of course it does not work either.
>
>     What am I doing wrong?  Any tips?
>
>     Thanks you.
>
>     Alok Bohara
>
>
>     -- 
>     Alok K. Bohara, Ph.D.
>     Professor
>     Department of Economics
>     University of New Mexico
>     Albuquerque, NM 87131,USA
>     Ph: 505-277-5903/5304(w)
>     Fax:505-277-9445
>     email: bohara at unm.edu <mailto:bohara at unm.edu>
>     http://www.unm.edu/~econ/faculty/professors.html
>     <http://www.unm.edu/%7Eecon/faculty/professors.html>
>     Nepal Study Center: http://nepalstudycenter.unm.edu
>     <http://nepalstudycenter.unm.edu/>
>
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>


-- 
Alok K. Bohara, Ph.D.
Professor
Department of Economics
University of New Mexico
Albuquerque, NM 87131,USA
Ph: 505-277-5903/5304(w)
Fax:505-277-9445
email: bohara at unm.edu
http://www.unm.edu/~econ/faculty/professors.html
Nepal Study Center: http://nepalstudycenter.unm.edu