Correspondence is a framework for interactively visualizing correspondences between items in related blocks.
When comparing two blocks, granularity of corresponding items can be chosen based on the relationships between the two blocks.
With three (or more) blocks, there is no clear best choice of granularity, because for each block, there are multiple relationships competing to determine the granularity.
A solution to this problem is to choose item numbers based on the finest granularity, and then use multiple IDs for items that refer to multiple items in other blocks.
The mouse-over interaction is then augmented to include partial highlighting. An item will be partially highlighted whenever its IDs overlap with those of the selected item, but the partially hightlighted item has at least one ID which is not an ID of the selected item.
Applying this to the concepts of "siblings" and "cousins", for items that have the same ID as a selected item in the same block or different block respectively, this results in a total of six different types of highlighting:
So, for example, if the selected item had IDs of 1,2,3, then the following IDs for items in a different block would give these matches:
Note: currently the colour schemes I have implemented do the same coloration for "sibling" and "cousin", so there are actually only four distinct colorations, i.e. "selected", "match", "partial match" and "unrelated".
In the following example, partial matches are shown in the.
The primary use-case for Correspondence is to look at only two blocks at once, or, to look at more than two blocks where all the blocks can be decomposed into items with the same or very much the same granularity.
Trying to make sense of matches and partial matches adds considerable cognitive load, something that Correspondence is designed to reduce in the first place.
The main use-case for three-way visualization is for translations between natural language texts, where there is a high-quality "free" translation from the language being taught to the learner's own native language, and one wishes to simultaneously display the original text in the language being taught, a word-for-word translation created for display with Correspondence, and the original "free" translation, all at once. In this situation, partial matches will occur, but only between the first and third or the second and third versions – not between the first two, given that the second text is one that has been carefully constructed so as not to require any partial matches with the original text.
For a practical example, see the three-way visualization of Aotearoa (New Zealand's Māori National Anthem).
Correspondence is licensed under the GNU Lesser General Public License version 3.