Creating Constellation Diagrams
About the Constellation Applet
The Constellation Applet
provides interactivity for node and link diagrams that illustrate
data that is associative or requires an arc list. Node and link color
and size can be associated with specified data values.
Interactive features
of the Constellation Applet include pop-up data tips for links and
nodes, subsetting of links via an embedded scroll bar, pan and zoom,
and several node and link selection modes. You can define drill-down
URLs for nodes, specify menu text for the drill-down action, insert
a background image, and specify a drill-down URL for the background
image, among other enhancements. You can also specify your own JavaScript
methods to define responses to drill-down actions.
The Constellation Applet,
like the Treeview applet, differs from the other applets in that
the diagrams that they display are not generated by SAS/GRAPH procedures. The DS2CONST macro generates
and formats an HTML output file, and specifies the appearance and
behavior of the node and link diagram based on values in a data set.
When to Use the Constellation Applet
The Constellation Applet
is best used to illustrate relationships between links and nodes,
which can be shown in affinity, sequence, and Web-click path diagrams,
for example. Colors, link line widths, and link directional indicators
can be specified to illustrate relationships. Pop-up data tips can
be specified for nodes and links, along with drill-down URLs for nodes
and for an optional background image. For diagrams that illustrate
associative data, an embedded scroll bar subsets the data in the diagram
dynamically.
The Constellation Applet
cannot be used to display hierarchical data. To create hierarchical
diagrams such as organizational trees, use the TreeView Applet. For
information about the Treeview Applet, see Creating Treeview Diagrams.
Programming with the DS2CONST Macro for the Constellation Applet
The DS2CONST macro enables
you to generate complete Web presentations for the Constellation Applet.
The macro has a large number of arguments that you can use to generate
and format an HTML output file, configure the diagram, and describe
how data sets and variables are to be applied to the diagram.
The macro arguments
are structured so that you can associate a variable with an aspect
of the diagram. The values of the variable are then used for that
part of the diagram. For example, the NLABEL argument specifies the
name of the variable whose values define the text labels that are
to be applied to the nodes. Other arguments provide default values
that are used when no variable value is provided.
Descriptions of all
of the arguments of the DS2CONST macro are provided in DS2CONST Macro Arguments.
Run the following code
to use the DS2CONST macro to generate the Web presentation for the
Constellation Applet shown in the picture above. (Note that the ODS
LISTING destination must be open when you run the DS2CONST macro.)
/* Define the path to the archive file, the HTML output file, and the SAS library */ %let jarfiles = path-to-archive-files; %let htmlfile = html-filename.htm; %let lib = WORK; /* put everything in the WORK library */ /* Define the node names and locations. */ data &lib..regions; length regionName $80 /* Node text label */ regionId $4 /* Node identifying string */ xLoc yLoc 8; /* Pixel position of node */ input regionID xLoc yLoc reserve RegionName $ &; cards; PNW 30 30 8.5 Western Systems Coordinating Council - Pacific Northwest NWPE 100 60 8.5 Western Systems Coordinating Council - Northwest Power Pool East CALI 40 220 9.5 Western Systems Coordinating Council - California RMPA 140 180 10.8 Western Systems Coordinating Council - Rocky Mountain Power Area AZNM 110 310 12.9 Western Systems Coordinating Council - AZNMSNV MAPP 180 80 15 Mid-continent Area Power Pool SPPN 185 200 13.6 Southwest Power Pool - North SPPS 170 270 13.6 Southwest Power Pool - South ERCT 180 400 15 Electric Reliability Council of Texas WUMS 270 90 17 Wisconsin - Upper Michigan MANO 290 240 17 Mid-America Interconnected Network - South ENTG 290 360 12.4 Entergy MECS 350 130 15 Michigan Electric Coordination System ECAO 360 200 15 East Central Area Reliability Coordination Agreement - South TVA 360 300 12.4 Tennessee Valley Authority SOU 390 400 12.4 Southern Company FRCC 420 460 15 Florida Reliability Coordinating Council VACA 450 340 12.4 Virginia and Carolinas MACS 460 280 19 Mid-Atlantic Area Council - South MACE 495 235 19 Mid-Atlantic Area Council - East MACW 430 220 19 Mid-Atlantic Area Council - West UPNY 450 160 18 Upstate New York DSNY 500 170 18 Downstate New York NYC 530 200 18 New York City LILC 570 170 18 Long Island Lighting Company NENG 570 90 18 New England Power Pool ; run; /* Define the node connections. */ data &lib..links; length from to $4 ltip $12 lcolor $8; format capacity comma.; input from to capacity; lcolor = "#BBBBBB"; /* Light gray lines */ ltip = left(put(capacity, comma.) || " MW"); /* Define the tool tips */ if capacity < 500 then width = 1; /* Define the line widths */ else if capacity < 1000 then width = 2; else if capacity < 2000 then width = 3; else if capacity < 3000 then width = 4; else width = 5; cards; MECS ECAO 2250 ECAO MECS 2250 ECAO MACW 2957 ECAO MANO 1655 ECAO TVA 1890 ECAO VACA 2334 ERCT SPPS 635 MACE MACW 1500 MACE DSNY 1130 MACS MACW 1800 MACS VACA 3075 MACW ECAO 2612 MACW MACE 3368 MACW MACS 3075 MACW UPNY 481 MANO ECAO 3033 MANO WUMS 608 MANO MAPP 531 MANO SPPN 1191 MANO TVA 2207 MANO ENTG 1245 WUMS MANO 1080 WUMS MAPP 676 MAPP MANO 1150 MAPP WUMS 324 MAPP SPPN 1172 MAPP ENTG 1000 MAPP NWPE 150 MAPP RMPA 233 NENG DSNY 1425 UPNY MACW 1418 UPNY DSNY 3750 DSNY LILC 788 DSNY MACE 308 DSNY NENG 1125 DSNY UPNY 3750 DSNY NYC 3750 NYC LILC 788 NYC DSNY 3750 LILC DSNY 938 LILC NYC 788 SPPN MANO 1228 SPPN MAPP 891 SPPN SPPS 525 SPPN ENTG 636 SPPS ERCT 569 SPPS ENTG 636 SPPS SPPN 900 SPPS AZNM 315 SPPS ENTG 1200 ENTG SOU 1136 ENTG TVA 1278 ENTG MANO 1399 ENTG SPPS 292 ENTG SPPN 292 ENTG MAPP 856 SOU FRCC 4516 SOU TVA 1810 SOU VACA 1346 SOU ENTG 1902 FRCC SOU 21 TVA ECAO 2235 TVA MANO 2331 TVA SOU 2052 TVA ENTG 2153 TVA VACA 2261 VACA ECAO 2822 VACA MACS 2794 VACA SOU 3042 VACA TVA 2240 CALI PNW 4922 CALI AZNM 0 CALI NWPE 1184 PNW CALI 5903 PNW NWPE 1050 RMPA MAPP 233 RMPA AZNM 518 RMPA NWPE 413 NWPE RMPA 413 NWPE CALI 1574 NWPE MAPP 113 NWPE AZNM 840 NWPE PNW 2145 AZNM CALI 5663 AZNM NWPE 638 AZNM RMPA 518 AZNM SPPS 315 ; run; /* Close the ODS HTML destination and open the ODS LISTING destination. */ ods html close; ods listing; /* Set chart title. */ title1 "Electric Power Regional Interconnections"; title2 "Created with SAS/GRAPH Constellation Applet"; footnote1 "Link: Base Electricity Transfer Capacity"; footnote2 "Node: Generation Reserve Margin"; /* Use the DS2CONST macro to generate the chart. */ %ds2const(/* Arguments for the Applet Tag */ codebase=&jarfiles, /* Path to archive file */ height=520, /* Applet window height */ width=600, /* Applet window width */ /* Arguments for Data Definition */ datatype=assoc, /* Size nodes by nvalue var */ nsize=reserve, /* Node sizes */ ncolval=reserve, /* Node colors */ layout=user, /* Use nx/ny to position nodes */ nx=xLoc, /* x-coordinate of node */ ny=yLoc, /* y-coordinate of node */ lcolor=lcolor, /* Link color */ lvalue=width, /* Link values */ lwidth=width, /* Link widths */ minlnkwt=0, /* Sets minimum link weight displayed*/ labels=y, /* Display node labels */ linktype=line, /* Do not show flow direction */ ndata=&lib..regions, /* Node data */ ldata=&lib..links, /* Node linkage data */ nid=regionID, /* Var for node ID string */ nlabel=regionID, /* Var for node label string */ lfrom=from, /* Var for from-node ID */ lto=to, /* Var for to-node ID */ ntip=RegionName, /* Var for popup node text */ ltip=ltip, /* Var for popup line text */ /* Arguments for Generating HTML and XML Files */ htmlfile=&htmlfile, /* Output file name */ openmode=replace, /* Create a new html file */ /* Arguments for Diagram Appearance */ nodeshap=circle, /* Node shape */ border=y, /* Enclose diagram */ colormap=y, /* Use colormap for link/node colors */ fntsize=14, /* Node label font size */ fntstyl=plain, /* Node label font style */ /* Arguments for Page Formatting */ bgtype=color, /* Use page background color */ bg=#DDDDDD, /* The page background color */ center=y, /* Center chart on the page */ septype=none, /* No separator line */ /* Arguments for the SAS TITLE and FOOTNOTE Tags */ tcolor=#0000FF, /* Title text color */ fcolor=#0000FF, /* Footnote text color */ tsize=3, /* Title text size */ fsize=2); /* Footnote text size */ /* Close ODS LISTING and open ODS HTML. */ ods listing close; ods html;
Arguments in the DS2CONST
macro identify the name of the nodes and links data sets. In the nodes
data set, arguments identify a node ID variable and a node label variable.
Other arguments identify the links data set and the variables that
define the nodes at the start and end of each link line.
For information about
more complex presentations for the Constellation Applet, see Enhancing Presentations for the Constellation Applet.