Sometimes, I pick something fun to do with SAS/GRAPH so that I can learn and experiment with some of the more obscure functionality that I'm wanting to master. This is one of those situations. This fun graph allowed me to experiment with crosshatch patterns in maps, overlapping map areas and creating 'holes' in maps.

The following is actually SAS/GRAPH 'Proc GMap' output!

Can you read the hidden message?!

What I learned:

• You have to specify GMap crosshatch patterns in the pattern statement 'differently' than you do for GChart.
• You can create 'holes' in a GMap by specifying 'SAS missing' values in the prior observation.
• Since cross-hatch patterns have "see through" backgrounds, if you're overlapping map areas that have crosshatching and don't want the patterns to be combined, then you should also overlap a same-shaped solid white map area between them.

Here's the code I used if you want to try this at home:

<pre>

%let name=psychedelic;
filename odsout '.';

/*
Similar to
http://sphotos.xx.fbcdn.net/hphotos-snc7/310824_264018990302225_100000823797837_652046_46651538_n.jpg
*/

data background;

value=1;
letter=0;
x=0; y=0; output;
x=210; output;
y=130; output;
x=0; output;

run;

/* make the holes for the letters */

/*
x=.; y=.; output;
x=10; y=70; output;
x=20; y=70; output;
x=20; y=120; output;
x=10; y=120; output;

x=.; y=.; output;
x=40; y=70; output;
x=70; output;
y=80; output;
x=50; output;
y=110; output;
x=70; output;
y=120; output;
x=40; output;

x=.; y=.; output;
x=80; y=70; output;
x=90; output;
y=90; output;
x=100; output;
y=70; output;
x=110; output;
y=120; output;
x=80; output;
*/

data letters;

letter=1;   /* I */
x=10; y=70; output;
x=20; output;
y=120; output;
x=10; output;

letter=2;  /* C */
x=40; y=70; output;
x=70; output;
y=80; output;
x=50; output;
y=110; output;
x=70; output;
y=120; output;
x=40; output;

letter=3;  /* A */
x=80; y=70; output;
x=90; output;
y=90; output;
x=100; output;
y=70; output;
x=110; output;
y=120; output;
x=80; output;
/* and the 'hole' in the top of the 'A' */
x=.; y=.; output;
x=90; y=100; output;
x=100; output;
y=110; output;
x=90; output;

letter=4;  /* N */
x=120; y=70; output;
x=130; output;
y=100; output;
x=150; y=80; output;
y=70; ouptut;
x=160; output;
y=120; output;
x=150; output;
y=100; output;
x=130; y=120; output;
x=120; output;

letter=5;  /* T */
x=180; y=70; output;
x=190; output;
y=110; output;
x=200; output;
y=120; output;
x=170; output;
y=110; output;
x=180; output;

letter=6;  /* S */
x=10; y=10; output;
x=40; output;
y=30; output;
x=20; y=50; output;
x=40; output;
y=60; output;
x=10; output;
y=40; output;
x=30; y=20; output;
x=10; output;

letter=7;  /* L */
x=50; y=10; output;
x=80; output;
y=20; output;
x=60; output;
y=60; output;
x=50; output;

letter=8;  /* E */
x=90; y=10; output;
x=120; output;
y=20; output;
x=100; output;
y=30; output;
x=120; output;
y=40; output;
x=100; output;
y=50; output;
x=120; output;
y=60; output;
x=90; output;

letter=9;  /* E */
x=130; y=10; output;
x=160; output;
y=20; output;
x=140; output;
y=30; output;
x=160; output;
y=40; output;
x=140; output;
y=50; output;
x=160; output;
y=60; output;
x=130; output;

letter=10;  /* P */
x=170; y=10; output;
x=180; output;
y=30; output;
x=200; output;
y=60; output;
x=170; output;
/* and the 'hole' in the top of the 'P' */
x=.; y=.; output;
x=180; y=40; output;
x=190; output;
y=50; output;
x=180; output;

run;

/* This goes with pattern2, to "white out" the letters */
data letters_2; set letters;
value=2;
run;

/* This goes with pattern3, to do the left hatchmark pattern */
data letters_3; set letters;
letter=letter+1000;
value=3;
run;

/* Now put all 3 map data sets together */
data my_map;
set background letters_2 letters_3;
run;

goptions xpixels=800 ypixels=598;
goptions device=gif;
goptions noborder;

ODS LISTING CLOSE;
ODS HTML path=odsout body="&name..htm" (title="Hidden Message") style=minimal;

pattern1 c=blue v=m2n45;
pattern2 c=white v=msolid;
pattern3 c=blue v=m2n315;

title1 ls=2.0 h=20pt font="albany amt/bold" color=gray55
 "Can You Read The Hidden Message?";

proc gmap map=my_map data=my_map;
id letter;
choro value / discrete
 coutline=white nolegend
 des='' name="&name";
run;

quit;
ODS HTML CLOSE;
ODS LISTING;
</pre>