An effective information visualization presents the all the various information
we need to make a decision in this intuitive visual form that permits to readily
understand, interact with and make decisions.
they may require the user to create a mental model, that is, some model of
understanding of how all these various pieces of information interrelate.
Charts: Simple representations of one or two attributes
A simple bar chart or pie chart transforms this data into a simple representation
permitting the viewer to visually compare similar values thereby removing the
need for the viewer to calculate the arithmetic. This includes the charts and
graphs most people are familiar, such as those found in Microsoft Office and
many "dashboard" products; as well as specialized charts such as
financial charts (e.g. open-close-hi-low chart, candlestick chart), statistical
charts (e.g. box-plots) and other chart types (e.g. bubble charts, network
diagrams).
However, simple charts are not adept at conveying multi-variate data, that is,
data with many attributes. Some charts attempt to use visual attributes such as
size, color and/or 3D to add additional variables, but overall charts are designed and limited to a few key
variables.
Linked Charts: Adding variables with additional charts
Linked charts overcome the limitations of a single chart, by linking various charts
representing different attributes. The simplest form of a linked chart, is simply
to align two charts with a common variable. For example, many stock charts show
daily stock price as a line chart, and show daily volume as a bar chart immediately
aligned underneath the price chart. A spike in the volume chart typically is aligned
with a strong change in the price of the stock.
Another means of linking charts together is through interaction.
For example, one chart may indicate the number
of owners of each automobile type, a second chart may indicate the salary levels
of the automobile owners and a third chart may indicate their age. Clicking on the
bar representing owners of sports cars, updates all the other charts to indicate the
proportion of owners owning these sports cars and perhaps may reveal a large number of
middle aged men in upper income brackets own these sports cars.
ADVIZOR Solutions' ADVIZOR and COGNOS Visualizer represent two commercially available
systems utilizing some form of linked charts
Integrated Charts: Merging representations together
Linked charts force the viewer to understand the data through a palette of
pre-constructed visual representations - e.g. bar charts, line charts, pie charts,
etc. The most appropriate representation is dependent on the task: what is the viewer
trying to solve. If the viewer is interested in geographic or spatial attributes,
maps may be useful. If the viewer is interested in time attributes, animation or
cyclic representation may be useful. However, data that has geographic attributes does
not necessarily imply that the viewer is interested in geographic analyses. Hence
"automatic" visualizations may not generate what is in a viewer's interest and my
central belief that good visualizations must be designed! (Just as good architecture,
good web pages and good interfaces are all the result of thoughtful design.)These
visualizations, referred to as "custom visualizations", "tailor
visualizations", "designed visualizations", or "information
fusion" merge various data representation techniques together and are typically created by a multi-disciplinary team of designers,
engineers and the users (subject matter experts). Since effective merged representations are tailored
to the uses of their viewer, examples of effective integrated visualizations can
be seen in specialized applications such as: supply chain management (e.g. i2 technologies) stock market analysis (e.g. in use by NASDAQ, etc) data quality analysis (e.g. in use by Statistics Canada, etc) portfolio management (e.g. Northern Trust, etc).
See the data visualization gallery at www.oculusinfo.com
and www.advizorsolutions.com for more examples of
all kinds of visualizations.