Notice

  In this sp_plot package of macros includes 6 separate macros:
  sp_plot
  sp_plota
  sp_plotbx1
  sp_plotbx1x2
  sp_plotbx1x1x2
  fixlen

  Each macro has its own help file with explanations and examples which
  can be accessed by running the following code:

  %local_help(macro_name)

---------------------------------------------------------------------- 
%sp_plot
----------------------------------------------------------------------
   Create a 3 dimensional plot of a regression surface

Description

  The %sp_plot macro will create a 3 dimensional plot of a regression 
  surface based on the coefficients from two predictors in a 
  regression equation.  The graph can be saved as a .gif file and used 
  in a web page.  The code for this macro should end in a semicolon in 
  order to avoid unnecessary error messages in the log file.  The code 
  for this macro should end in a semicolon in order to avoid 
  unnecessary error messages in the log file.

Syntax

  %sp_plot(angle=0, x1lo=-10, x1hi=10, x1by=1, x2lo=-10, x2hi=10, 
           x2by=1, cons=0, bx1=0, bx2=0, bx1x2=0, bx1x1=0, bx2x2=0, 
           bx1x1x2=0, bx1x2x2=0, outfile=' ', data=_spinplt, 
           dev=gif373, title= "3-D Plot ",
           title2 = "y=&cons+&bx1*x1+&bx2*x2+&bx1x2*x1*x2",
           cmd=plot, plot=, gopt=, reset=yes); 


    angle   - angle of the graph in the x1,x2 plane
    x1lo    - the minimum value of the range of x1
    x1hi    - the maximum value of the range of x1
    x1by    - the spacing of the grid of the regression surface
    x2lo    - the minimum value of the range of x2
    x2hi    - the maximum value of the range of x2
    x2by    - the spacing of the grid of the regression surface  
    const   - the value of the constant in the regression function
    bx1     - the value of the coefficient of x1 in the regression 
              function
    bx2     - the value of the coefficient of x2 in the regression 
              function
    bx1x2   - the value of the coefficient of x1*x2 in the regression 
              function
    bx1x1   - the value of the coefficient of x1*x1 in the regression 
              function
    bx2x2   - the value of the coefficient of x2*x2 in the regression 
              function
    bx1x1x2 - the value of the coefficient of x1*x1*x2 in the 
              regression function
    bx1x2x2 - the value of the coefficient of x1*x2*x2 in the 
              regression function
    outfile - saves the graph as a .gif file with the given name    
    data    - saves the data with the given name
    dev     - specifies the graphic device used 
    title   - the title displayed at the top of the graph
    title2  - the second title displayed at the top of the graph
              the default is to display the regression function used
              to generate the graph 
    cmd     - specifies if the graph is a plot (the data points 
              define a surface) or a scatter plot (represents each 
              data point with a specified shape, the default is a 
              pyramid)
    plot    - specifies other options for the graph, the options 
              available willdepend on whether cmd was specified as 
              scatter or plot (plot is the default) 
    gopt    - specifies other goptions which can modify the detailed
              options on the size, color or the style of the plot
    reset   - determines if all the options that have been 
              specified are reset 


Examples

  %sp_plot(outfile='c:\sp_plot1.gif', angle=20, bx1=-2, bx1x2=-1 ); 
  
  %sp_plot(outfile='c:\sp_plot2.gif', angle=80,
           cons=1, bx1=-2, bx2=1.7, bx1x2=-2); 

  %sp_plot(outfile='c:\sp_plot3.gif',
           angle=20, bx1=-2, bx1x2=-1 ,
            x1lo=-3, x1hi=3, x1by=.4, x2lo=-2, x2hi=2, x2by=.4,
            plot= zmin=-12 zmax=18 );

  %sp_plot(outfile='c:\sp_plot4.gif',
           angle=20, bx1=-2, bx1x2=-1,  
           plot= grid ctop=green cbottom=red caxis=black); 

  %sp_plot(outfile='c:\sp_plot5.gif',
           angle=20, bx1=-2, bx1x2=-1 , cmd=scatter, 
           plot= noneedle grid shape='balloon');          

  %sp_plot(outfile='c:\sp_plot6.gif',
           angle=20, bx1=-2, bx1x2=-1 , cmd=scatter, 
           plot= shape='balloon', gopt = border); 
   
  %sp_plot(outfile='c:\sp_plot7.gif', bx1=1, bx2=-2, bx1x2x2=.1);


Author

  Michael Mitchell
  mnm@ucla.edu
  UCLA Academic Technology Services
  Statistical Consulting Group
  
Also See

  See a complete example in
    http://www.ats.ucla.edu/stat/sas/examples/aw/example_graphs.htm 
    http://www.ats.ucla.edu/stat/sas/teach/reg_int/reg_int_cont.htm
  
  For more details about the cmd, plot and gopt options please refer
    to following sections in the SAS Manuals
    http://sasdocs.ats.ucla.edu/gref/z3d-plot.htm
    http://sasdocs.ats.ucla.edu/gref/zscatter.htm
    http://sasdocs.ats.ucla.edu/gref/zonschap.htm

  Also see the macro itself from 
    http://www.ats.ucla.edu/stat/sas/macros/sp_plot.sas.txt

    
           
  Also see the books (http://www.ats.ucla.edu/stat/books/ )
    Multiple Regression: Testing and Interpreting Interactions 
      by Leona S. Aiken and Steven G. West 
    Interaction Effects in Multiple Regression by James Jaccard, 
      Robert Turrisi and Choi K. Wan