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The GREMOVE Procedure

Example 2: Creating an Outline Map of Africa

Procedure features:
PROC GREMOVE options:
DATA=
OUT=
Other features:
GMAP procedure
Sample library member: GR25N02

This example processes the MAPS.AFRICA map data set, supplied with SAS/GRAPH, to produce a new map data set that contains no internal boundaries. This is done by adding a new variable, REGION, to the map data set and setting it equal to 1. Unit areas from the input map data set that have the same BY-variable value are combined into one unit area in the output map data set. The MAPS.AFRICA Data Set shows the variables present in the original map data set:

The MAPS.AFRICA Data Set
                            MAPS.AFRICA Data Set
                 OBS     ID    SEGMENT       X          Y

                   1    125       1       0.57679    1.43730
                   2    125       1       0.57668    1.43467
                   3    125       1       0.58515    1.42363
                   .
                   .
                   .
                3462    990       1       1.04249    0.50398
                3463    990       1       1.04184    0.50713
                3464    990       1       1.04286    0.50841

Map before Removing Borders (GR25N02(a)) shows the map before processing:

Map before Removing Borders (GR25N02(a))

[IMAGE]

The new REFLIB.AFRICA map data set is created with a new variable, REGION. The REFLIB.AFRICA Data Set shows the variables that are present in the new map data set created by the GREMOVE procedure:

The REFLIB.AFRICA Data Set
                           REFLIB.AFRICA Data Set
               OBS       X          Y       SEGMENT    REGION

                 1    0.24826    1.02167       1          1
                 2    0.25707    1.02714       1          1
                 3    0.26553    1.03752       1          1
                 .
                 .
                 .
               982    1.19071    1.30043       3          1
               983    1.18675    1.30842       3          1
               984    1.18518    1.32822       3          1

Map after Removing Borders (GR25N02(b)) shows the new map after PROC GREMOVE has removed all of the interior boundaries:

Map after Removing Borders (GR25N02(b))

[IMAGE]

 Note about code
libname reflib 'SAS-data-library';
libname maps 'SAS-maps-library';
goptions reset=global gunit=pct border cback=white
         colors=(black blue green red)
         ftext=swiss htitle=6 htext=3;
 Note about code
data newaf;
   set maps.africa;
   region=1;
run;
 Note about code
proc gremove data=newaf out=reflib.africa;
   by region;
   id id;
run;
 Note about code
title 'Africa with Boundaries';
footnote j=r 'GR25N02(a) ';
 Note about code
pattern value=mempty r=50 color=blue;
 Note about code
proc gmap map=maps.africa data=maps.africa all;
   id id;
   choro id / nolegend;
run;
 Note about code
title 'Africa without Boundaries';
footnote j=r 'GR25N02(b) ';
 Note about code
proc gmap data=reflib.africa map=reflib.africa;
   id region;
   choro region / nolegend;
run;
quit;


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Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.