Graphics Reference
In-Depth Information
Figure
.
.
Zoom and pan
achieved without special programming in XML graphics because its rendering ap-
plications and plug-ins contain zoom and pan functions.
he tooltip function is used to display a variety of information types, such as data
labels and values in relation to a particular location or point indicated by the mouse
cursor.Detailedinformationishiddeninordertohelpuserstointuitivelyunderstand
the data through visualization. Tooltip is useful when users want to obtain informa-
tion on demand.
he layer function overlays various kinds of information in a single display area.
In this case, each type of information is called a “layer,” and users can select which
layers to display. In the case of geostatistical data, there are oten several types of
information - such as maps, locations of data points, roads, railways, institutions,
and results of statistical analyses - that need to be displayed. However, it is usually
desirabletodisplayonlyselectedlayersatanyonetime,becausedisplayingallofthem
at once will hinder comprehensibility. Examples of the use of the tooltip and layer
functions in SVG are shown in Fig.
.
. hese data, the Cities data of DASL (DASL
Project,
), were collected by the Economic Research Department of the Union
Bank of Switzerland. hey represent the economic conditions in
cities around in
world in
. he Cities data contain three variables: Work, Price and Salary. Work
is the weighted average of the number of working hours for
occupations. Price is
the index of the cost
goods and services, excluding rent (Zurich =
). Salary
is the index of hourly earnings for
occupations ater deductions (Zurich =
).
Figure
.
showsascatterplotofthefirsttwoprincipalcomponentscoresandcluster
regions. Each state label can be obtained by the tooltip by pointing with the mouse.
Furthermore, the elliptical regions show the two clustersobtained fromthe k-means
method. Checkboxes on the html forms can be used to specify whether the cluster
layer and the city labels layer should be visible or invisible.
