Visual Data Exploration Using Webbles - Webble Technology - page 125

DataValues ,aslotwherethe Dashboard inputs the data to be visualized, in
one of the formats specified by the previous slot.
GroupColors , XML indicating which group of data should be visualized in
what color. This slot is used to coordinate the use of color between all plugins
so that e.g. green dots on the map correspond to green bars in the histogram.
LocalSelections , a slot with a dictionary mapping data item IDs to group IDs.
The mapping shows which data items are selected, and in which group it has
been placed. The selections are the selections in this component only. If the user
has selected one group of data with speeds above 60 km/h and another group of
data with speeds below 10 km/h by selecting bars in a histogram, the dictionary
would map each ID belonging to data items with speeds above 60 km/h to group
1, IDs of data items with speeds below 10 km/h to group 2, and all other IDs to
group 0 (the unselected items).
GlobalSelections , also a dictionary mapping data item IDs to group IDs. Here,
the mapping shows the global selection status. A data item may be put into group
1 in one component but be unselected in another (globally unselected), or items
belonging to the same group in one component may be in different groups in
another component and thus be in different groups globally.
The Digital Dashboard coordinates the visualization components and aggre-
gates the information from them. When the local selections in one component
changes, the system updates the global selection status of any data items affected
and then updates all the visualization components affected by any changes.
The system also hides the data sources from the visualization components,
and transforms the data source XMLs to new XMLs with the data needed by
each visualization component, extracting wanted fields and removing unwanted
ones, and renaming the fields to the expected names. The system will try to
automatically connect data fields and visualization components. If there is only
one field of a certain type (e.g. only one time-of-day field) in the data, this field
is automatically assigned to all components that expect such a field. When there
are several fields to choose from, the system can make guesses or it can be left
to the user to select from a list of the fields of the correct type.
2.4 Wrapping Existing Functionality or Software
There are templates for making both visualization and data source plugins for
the Digital Dashboard . A template is a Webble that has the slots needed and
some skeleton code for common operations on slot changes, e.g. iterating over
the global selection dictionary. Building a new Webble that follows the Dashboard
interface is fairly easy but requires some programming knowledge.
Meme Media aims to reuse existing functionality and existing software can be
used in the Dashboard . An unrelated Webble that can visualize data, handle user
interaction, or interact with a data source, can be used by making an adapter
Webble. The adapter Webble just needs to transform the data etc. between the
format of the existing Webble and the format of the Dashboard . Depending on
how different these are, this could be very easy, e.g. an almost empty adapter