Together with Sebastian Ferré, I defined and illustrated some common navigation modes in faceted search and web applications dealing with metadata+resources in general for an upcoming publication. I am here sharing the gist of it already, as I believe these could be interesting for many of you.
So, here they are. They all refer to situations where there is a set of resources which can be filtered according to different criteria.
The most common pattern: Given a set of resources, select a subset by adding an additional (AND-connected) filter criterion.
All photos -> zoom in (Europe) -> photos taken in Europe
Photos taken in Europe -> zoom-in (Cities) -> photos taken in Europe AND taken in cities
The complementary pattern: Given a filtered view, select a superset by either
- Removing a (AND-connected) filter
Photos taken in Europe AND taken in cities -> zoom out (cities) -> photos taken in Europe
- or: Adding a OR-connected filter
Photos taken in Europe -> zoom–out-OR (Africa) -> photos taken in Europe OR Africa
- or: Replacing a filter with a more general version
Photos taken in Germany -> zoom–out-UP (Germany) -> photos taken in Europe
In either way, you end up with a more general query, that yields at least all of the original results, and usually more.
Zoom-in and zoom-out can be combined into a shift navigation mode. Here, one part of the filters is replaced by a concept that is neither more general nor more specific than the original one.
Photos taken in Germany -> shift (France) -> photos taken in France
Another combination of zoom-in and zoom-out is the pivot navigation. It is very common in web applications like e.g. delicious.com. Given a filter setting and its results, you can jump to a fresh query consisting only of one of the occurring metadata terms.
Photos taken in Germany -> pivot (Moritz) -> photos taken by Moritz
This is often accomplished by adding clickable links to the results’ metadata items.
Querying by examples
This corresponds to a pivot on a number of resources and metadata fields at the same time. The most specific concepts that apply to a whole item selection are collected and used in a new query.
Clinton, Bush, Obama -> query by examples -> American presidents
Obviously, the generalization capabilities here depend a lot on the metadata structure. In some database, the example above might generalize to “persons” or “males”, in others to “Male american presidents after 1980″.
Photos taken in Europe -> related set (photographer) -> Photographers of photos taken in Europe
I realize this is quite dry material and could use some illustrations, examples, references. Nevertheless, I hope it spawns some new thoughts in those of you thinking about search and browsing in web applications!