/*-----------------------------------------------------------------
            S A S   S A M P L E   L I B R A R Y                   
                                                                  
      NAME: SPPEX2                                                
     TITLE: Documentation Example 2 for PROC SPP                  
   PRODUCT: STAT                                                  
    SYSTEM: ALL                                                   
      KEYS: spatial analysis, spatial point patterns              
     PROCS: SPP                                                   
      DATA:                                                       
                                                                  
   SUPPORT: prmoha                                                
       REF: PROC SPP, EXAMPLE 2                                   
      MISC:                                                       
-----------------------------------------------------------------*/

proc spp data=sashelp.bei;
   process trees = (x,y /area=(0,0,1000,500) event=Trees);
   trend grad = field(x,y,Gradient);
   trend elev = field(x,y,Elevation);
   covtest trees = grad elev;
run;