Scalable Hemicycle Charts (SHecC)

This project aims to produce scalable hemicycle charts. Below is a short list of the features it intends to implement:

• Find an optimal distribution of the seats based on the following input parameters:
  • The number of mandates
  • The ratio between the inner and the outer radius of the hemicycle
  • The angle of the hemicycle
• Distribute the parties across the hemicycle, and mark each seat using:
  • The party color, or for electoral alliances, a set of colors
  • A circle or a polygon, a person shape or a seat shape
  • A character
  • Transparency to indicate probability
• Optionally, add a legend displaying:
  • The shape, the colors and the character per party
  • Party name
  • Number of mandates

Getting Started

First of all, you need to obtain a copy of the source code and compile it into an executable. Run the following commands to do this:

git clone git@github.com:filipvanlaenen/shecc.git
cd shecc
mvn clean compile assembly:single

If everything works well, you'll a JAR file in the target directory with all dependencies included. Navigate into the target directory and produce your first seating plan as folows:

cd target
java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar 19.FF0000..R,11.00FF00..G,48.0000FF..B

As you'll see, this will print the contents of an SVG file to the command line. You can redirect the output to an SVG file, and if you have Inkscape installed, convert it to a PNG file as follows:

java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar 19.FF0000..R,11.00FF00..G,48.0000FF..B > seating-plan.svg
inkscape -z -D seating-plan.svg -e seating-plan.png

The result should be something like this, a seating plan with 19 red seats, 11 green seats and 48 blue seats:

Seating Plan Specification

The number of seats per parliamentary group can be specified as follows:

• For each group, specify its size, followed by a dot, followed by its color as a six-digit hexademical number, followed by a dot, followed by a name, followed by a dot, followed by a character to be used in the circle
• Join all groups together, separating them with a comma
• Parliamentary groups will be placed in the hemicycle from left to right

The example from above, 19.FF0000..R,11.00FF00..G,48.0000FF..B can therefore be decoded as follows:

Now lets add names for the parliamentary groups. You can do this as follows (notice that you have to use quotes around the command-line argument if any of the names contains a space):

java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar \
  "19.FF0000.Red Party.R,11.00FF00.Green Party.G,48.0000FF.Blue Party.B" > seating-plan-with-legend.svg

Next, lets merge the red and the green party together with a yellow party into a red-green-yellow electoral alliance. You can specify a set of colors for a parliamentary group by concatenating each of the colors with a colon in between:

java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar \
  "30.FF0000:00FF00:FFFF00.Red-green-yellow Alliance.A,48.0000FF.Blue Party.B" > seating-plan-with-red-green-yellow-party.svg

Finally, differentiate between the seats that are certain, those that are likely, and those that are unlikely:

java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar \
  "24:29:30.FF0000:00FF00:FFFF00.Red-green-yellow Alliance.A,41:46:48.0000FF.Blue Party.B" > seating-plan-with-red-green-yellow-party-and-likelihoods.svg

Below is a more formal specification of the grammar in extended Backus-Naur form:

letter              = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | "N"
                    | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" | "a" | "b"
                    | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p"
                    | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z" ;
digit               = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
hexademical digit   = digit | "A" | "a" | "B" | "b" | "C" | "c" | "D" | "d" | "E" | "e" | "F" | "f" ;
integer             = digit , { digit } ;
size                = integer ;
sizes               = size , { colon , color } ;
color               = hexademical digit , hexademical digit , hexademical digit , hexademical digit ,
                      hexademical digit , hexademical digit ;
colon               = ":" ;
colors              = color , { colon , color } ;
character           = letter | digit ;
space               = " " ;
name                = { letter | digit | space } ;
dot                 = "." ;
group specification = sizes , dot , colors , dot , name , dot , character ;
comma               = "," ;
seating plan        = group specification ,  { comma , group specification } ;

Chart Configuration and Styling

There are a few command-line options available to style and configure the chart produced. The table below gives an overview.

The following command will produce a chart having a hemicycle with an angle of 150° using the Lato font, and with a dark blue as the font color, with a title and a subtitle:

java -jar shecc-1.0-SNAPSHOT-jar-with-dependencies.jar \
  "19.FF0000.Red Party.R,11.00FF00.Green Party.G,48.0000FF.Blue Party.B" \
  --font-color=000077 --font-family=Lato --subtitle="A sample seating plan" \
  --title="Seating Plan" --angle=150 > styled-seating-plan-with-legend.svg