data lidar17; set Plot17lidar;
/* Plot17lidar is a subset of a comma-delimited dataset that had approximately 600,000 	*/
/* height observations recorded in a 4x4 meter grid; there are many instances of  */
/* duplicate heights at the same X,Y coordinates    */
UTMEast=X;
UTMNorth=Y;
Height=Z;
Drop x y z;
run;
/* The first sort, which does not eliminate duplicates, may not work with some SAS PROCs. */
/* E.g., the contour procedure did not work in earlier versions of SAS */
/* Compare the dataset sizes from these two SORTs; only the first Height for  */
/* each (UTMEast,UTMNorth) combination is saved   */
proc sort data=lidar17; by UTMEast UTMNorth; run;
proc sort nodupkey data=lidar17 out=unique17 dupout=leftovers; by UTMEast UTMNorth;
/* The DUPOUT statement saves all the deleted duplicate observations */
run;

proc print data=unique17  (obs=30);
run;

proc print data=leftovers (obs=30);
run;

/* 3-dim graphics     */

/* Data is too "spiky" for contour plot */
/* Some of the features are real though--the plot straddled a jeep road */
proc gcontour data=unique17;
plot UTMEast*UTMNorth=height;
run;

proc g3d data=lidar17;
scatter UTMEast*UTMNorth=height/noneedle;
run;

/* Fix the symbol size on the above plot.  See the jeep road? */
proc g3d data=lidar17;
scatter UTMEast*UTMNorth=height/noneedle shape="balloon" size=0.1;
run;