Visualization Scales

Introduction

Sometimes more than showing one information in the visualization of data points is wished. For example, drawing counties in a Map Chart shows the shapes of counties. The drawing of the shapes of counties does not easily give more information than just the outlook of counties. The color and paint with which the shapes are drawn could be used for expressing some information, but the specifying of colors and paints for showing information can be tedious. Furthermore, telling to the viewer what information color and paint represent would require additional work.

Visualization scales are designed for expressing additional information in the visualization of data points. With the scales, more than one information in the visualization of data points can be achieved easily. The information that scales represent is shown with a Legend Chart.

Data for Scale Visualization

Data points have data with which the points are visualized. If a scale visualization for the data points is wished, data for the scale visualization has to be added for the data points. Adding the data for scale visualization is similar to the adding of values of data points. For example, data for paint scale visualization for three data points can be given as:

<column dataType="INT" type="paint">
 <element>98</element>
 <element>21</element>
 <element>56</element>
</column>

Specifying the Scale Visualization

The data for scale visualization is not enough for using scale visualization. The rules for the visualization of the data values given for the scale have to be defined. The defining of the visualization rules is done inside a plot or series tag. For example, rules for a paint scale visualization can be defined as:

<paintScale dataType="PAINT">
  <paintPoint interpolationMode="linear"
              paint="yellow"
              minPaint="red"
              position="100"/>
  <paintPoint paint="null" position="0"/>
</paintScale>

According to these definitions, visualization of paint scale for data points would happen as follows:

Value for paint scale	Paint
<= 0	null (corresponds to no paint)
1	red
1 < value < 100	paint changes linearly from red to yellow
100	yellow
> 100	no paint

With these definitions, the values of the data for paint visualization would translate roughly to:

98 - practically yellow
60 - orange with a hint of yellow
21 - red with a hint of orange

Color Scale

Color scale shows information with the paint with which the line, which usually translates to a border, of the visualization of a data value is drawn.

Paint Scale

Paint scale shows information with the paint with which the interior area of the visualization of a data value is drawn.

Shape Scale

Shape scale shows information with a shape that is added to the visualization of a data value.

With shape scale, linear interpolation is not currently supported. Therefore, only points with fixed shapes can be used.

Examples

Color scale example.

Paint scale example.

Shape scale example.