The Table Lens is a common information visualization method to dynamically explore large amounts of tabular data. Borrowing from the spreadsheet model, the Table Lens displays regional data values in columns and rows without scrollbars and without obscuring any data and filling the cells with scaled and coloured horizontal small bars. Each row in the Table Lens represents a single region and the columns represent a specific indicator. The power of the Table Lens is that it has the combined abilities to sort records, focus “zoom” in on interesting areas in the data (to reveal exact numerical information) and remove unwanted records.
Figure: The Table Lens here with 3 selected indicators and all OECD EU TL2 regions. The first column shows the name of the region followed by the selected indicators and their data values (same as a spreadsheet).
The advantage of the Table Lens is obtained by using a so-called “focus + context'' or “fisheye'' technique. These techniques allow interaction with large information structures by dynamically distorting the spatial layout of the structure according to varying interest levels. The relationship between focus and context supports searching for patterns in the big picture and dynamically investigating interesting details without losing framing context. The most significant feature of a table is the regularity of its content with information along rows or columns is consistent. This is reflected in the fact that regional tables usually have the name of the region at row and column edges that identify associated indicator data values. The Table Lens adjusts the layout of a table without bending any rows or columns as illustrated in the figure above. Table Lens can be used to explore patterns in regional tables and investigate various explanatory statistics using multivariate dataset.
The following interactive features are supported:
- Sort by clicking on columns.
- Rearrange indicator columns by dragging-and-dropping in a GUI table panel.
- Focus by clicking on a cell or by clicking and dragging to focus a whole row or multiple rows.
- Filter regions to create smaller, more specific datasets.
- Spotlight data to track particular information as you sort.
To sort the regions in the Table Lens simply click on the header of the column that you want to sort by, clicking multiple times on the same header will reverse the order of the records.
The zoom capabilities in the Table Lens work by clicking and dragging with the mouse. To select an area to zoom in on click and hold the left mouse button on the record that you want the area to start with. Then drag the mouse downwards until the regions of interest is covered by the light blue rectangle that appears when you start to drag, to complete the selection release the mouse button. The selected regions will be enlarged to reveal exact numerical values as well as the horizontal bar representation.
To deselect an area of regions click and hold the left mouse button on the regions that you want the area to start with and then drag upwards instead of downwards, the records covered by the rectangle will be deselected. You can also use the button labelled "Reset selection" in the settings panel located beneath the Table Lens component to deselect all records. The Table Lens can also be used to filter away unwanted records from the data set, this is done by first selecting the regions that should be removed followed by clicking the button labelled "Filter away selected" in the Table Lens settings panel. This can be done repeatedly. To reset this filter click the button labelled "Reset selection" in the Table Lens settings panel.
Figure: The regions in the Table lens are sorted after the fifth indicator column “Tertiary Education”. Only regions with highest education value are shown using the “Filter Away” operation.
Test and evaluate this educational here: Table Lens Vislet:
Figure: Table Lens from worldBank indicators. Indicator "ageing population 65+" is selected and sorting applied. The countries with highest ageing population are listed. The features and performance of a Table Lens can be tested and evaluated in the World eXplorer Demonstrator http://mitweb.itn.liu.se/GAV/world/
Last updated: 2013-12-09