Date: Mon, 14 Apr 2008 16:31:33 -0700
Reply-To: Dale McLerran <stringplayer_2@YAHOO.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Dale McLerran <stringplayer_2@YAHOO.COM>
Subject: Re: How do I display a likelihood surface in multiple dimensions
using SAS graph
In-Reply-To: <200804111408.m3BAkrY7029770@malibu.cc.uga.edu>
Content-Type: text/plain; charset=iso-8859-1
Randall,
Here is what I would suggest if you have the Insight procedure
licensed. You really want to plot six dimensions here (the five
parameters and the function value). That is an awful lot to try
to convey in a single plot. But I think we can get you there
(or at least mighty close to what you want).
Open up your data in PROC INSIGHT. Under the Analyze tab, select
a rotating plot. Select your functional value as Z and two of your
parameters as Y and X respectively. While the window for selecting
X, Y, and Z dimensions is still open, select the Output button and
from there select the "Fit Surface" box. Select OK to get a
three-dimensional plot. Rotate the plot using the tools on the
upper left side of the Rotating Plot window to get a good perspective.
You now have a three-dimensional figure (something that can be
generated in just about any graphics software package).
In order to add information about additional dimensions, we can
use a color gradient to represent one additional parameter (a fourth
dimension) and differential symbols to represent yet another
parameter (a fifth dimension). In order to add a color gradient
and differential symbols, select the Edit tab. In the drop down
box, select Windows-->Tools. Now, select the color gradient bar
and then click on a parameter that represents the fourth dimension.
Go back to the Tools window and select the symbol gradient bar and
then apply the symbol gradient to a parameter representing a fifth
dimension. (You may want to adjust the symbol size so that symbols
display well. To adjust the symbol size, do as follows. Make the
Rotating Plot window the active window. Right click within the box
that defines the plot area. Select Marker Size and adjust up or
down to best suit your need.)
The final dimension can be examined by brushing. Brushing is an
interactive highlighting of selected observations. The best way to
brush across the fifth parameter is to go back to the Analyze tab
and select Scatter Plot. Generate a scatter plot for the parameter
of interest (the sixth dimension) along with one other variable
(this could be one of the parameters already selected.) In the
Scatter Plot window, draw a frame around one level of the parameter
which is to represent the sixth dimension. Now, while the Scatter
Plot window is the active window, make sure that you can see the
Rotating Plot window. In the Scatter Plot window, drag that frame
that selects observations across the scatter plot. This will
highlight values of the fifth parameter in the Rotating Plot window
allowing some visualization of the effect of the sixth dimension.
I'm glad that you did not indicate that you had six parameters.
Trying to represent six dimensions on a two-dimensional space is
hard enough as it is!
HTH,
Dale
--- Randall Powers <powers_r@BLS.GOV> wrote:
> Hi All.
>
> I have a function which has five parameters. I'm looking to plot a
> display
> such that I'm fixing the values of three of the parameters, and
> varying the
> other two. I was told that I should somehow be able to do this using
> SASGraph.
>
> I know that SASGRaph has a PROC G3D statement, but it seems that here
> you
> are dealing with three variables, whereas I have FIVE. How do I deal
> with
> five?
>
> Thanks!
>
---------------------------------------
Dale McLerran
Fred Hutchinson Cancer Research Center
mailto: dmclerra@NO_SPAMfhcrc.org
Ph: (206) 667-2926
Fax: (206) 667-5977
---------------------------------------
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