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.

Zoom–in

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

Zoom–out

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.

Shift

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

Pivot

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″.

Related set

Demon­strated in par­al­lax and hum­boldt, this nav­i­ga­tion mode fol­lows the same meta­data link on the whole result set to con­struct a new one.

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!