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By Sandra Schloen, June 2020
Visualization Wizard (VizWiz): Charts
Visualization Wizard (VizWiz): Charts
OCHRE's Visualization Wizard, the VizWiz, supports basic charting features, drawing upon project data to create pie charts, line charts, bar charts, and more, along with some optional statistics functions.
Consult the main Visualization article for general information about this feature.
Overview
Overview
Overview of wizard options
Overview of wizard options
For charting, from the VizWiz choose:
Type of Visualization: Chart
Keep in mind that the nature of the items in the set may fit one of these types better than another.
For example, you will not produce a meaningful network graph from counts of pottery. You will not produce a meaningful bar chart from social network nodes.
Content (top tab)
This tab provides a summary of items in the set on the Items tab.
Subsumed on this tab also is the Format tab, see following.
Format (left tab)
This tab provides customization options, described below.
The Data option typically represents a numeric property plotted along the y-axis; examples include "Quantity," "Weight," etc. OCHRE will present appropriate numeric properties attested on the list of items to be charted.
The Series option typically represents a nominal or ordinal property plotted along the x-axis representing categories of data (in this example, "Ware" types). OCHRE will present appropriate nominal/ordinal properties attested on the list of items to be charted.
The Group-by option represents a further breakdown of the Series option (in this example, "Phase" items). Variables provided as a Group-by option are the same as those provided for a Series option.
Additional Charts options provide a variety of ways to customize the format and display of the chart.
Click the Draw Chart button to produce the Chart.
Use the Save button on the Chart menu to save the chart graphic as a PNG image.
For example, the specifications to produce the above chart are:
Base Chart Options on the Set Specifications, checked on
Data option: Quantity
Series option: Ware
Group-by option: Period type
Chart type: Bar chart, stacked
Sort option: Value, descending
Case Study Gallery
Case Study Gallery
Charting, for Pottery analysis: East of the Theater at Corinth (ETC) XIX
Charting, for Pottery analysis: East of the Theater at Corinth (ETC) XIX
Charting, for Speaker analysis: The Taming of the Shrew (CEDAR-DV)
Charting, for Speaker analysis: The Taming of the Shrew (CEDAR-DV)
Stipulations and Validity Checking
Stipulations and Validity Checking
Not all combinations of options make sense. It is up to the user to some extent to make appropriate selections, but OCHRE tries to help by giving instructive feedback when inappropriate selections are made. Some conditions and considerations are described here:
The Title of the Chart is derived from the Name of the Set. The labels for the axes are derived from the names of the relevant variables selected for those axes.
A Variable for data is required unless the requested Statistics option is simply Count, in which case OCHRE will count the instances of each nominal or ordinal Value based on the Series option's chosen Variable. (See the "Place of manufacture" example above.) The Data option generally determines the values along the y-axis (or the values of the pie slices).
If multiple Data options are provided, the Sort options of Value ascending/descending will be quietly ignored, since there is not a clear basis for the sort among the multiple options.
A Series option is generally required in all cases; this determines the categories along the x-axis (or the categories of the pie slices).
If a Group-by option is chosen, it cannot be the same Variable as that chosen for the Series option.
If a Group-by option is chosen, there can be only one Data option. Stated another way, if there are multiple Data options chosen, there can be no Group-by option. That is, the additional dimension (provided by multiple lines/bars, or by stacked bars/areas) can represent either multiple Data options or a Group-by option, not both.
Sort options, Top-N, and Consolidate-below options are applied to the selected Series variable. If the chart shows a further breakdown by Group, the Sort, Top-N and Consolidate-below options based on the Series variable are maintained (only split further by group, as applicable).
The Percentage Data option is only valid for the Sum (default) statistic. Otherwise OCHRE will quietly ignore this setting.
If Periods are used as the Group-by option for a Chart, they are automatically sorted by sequence; it doesn't make sense to sort them any other way.
The Exclude <unassigned> items checkbox lets the user remove from consideration items whose property values for the Series and/or Group-by options are <unassigned> or blank. This is valid for charts that report the actual values of the Data option(s), but not for charts that report on percentages. Checking this option for charts such as pie charts and stacked charts (bar/area) is not valid as those chart types report on percentages and must include the whole set of data for consideration in order not to be misleading. Note that an <unassigned> category might suggest that there are gaps in the data that should be corrected.
If items have multiple assignments (to properties or periods for example), only the first one encountered is used so as not to over-state the data by using it more than once.
(Stacked area charts, bubble charts, and scatter charts are not yet available.)
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