Step 2 of 10: Navigation

A 'scalable' approach to navigation

By far, the most important user interface component for tree visualization is navigation. Phylogenetic trees often have such a complex structure that simply looking at static picture is completely uninformative; instead, we need a method which allows us to access the information present at multiple scales within the tree structure.

In short, we need a way to pan and zoom.

PhyloWidget approaches this problem with two simple but powerful navigational tools. Click below to rev 'em up.

With a simple flick of the wrist (or rather a click of the button), you now have the capability to quite easily zoom and pan around our tree! It can get boring with just a single node in our tree, so let's load up a slightly more complex example:

With this larger tree, you can begin to see the usefulness of PhyloWidget's emphasis on zooming: with a single click of the mouse, you can move from viewing this tree in its entirety down to analyzing a single node. You may also have noticed that the node labels always remain readable and are never overlapping each other; this is a unique feature of PhyloWidget's rendering engine, and is covered in more detail in the next vignette.

Getting lost in the forest

It's okay to get lost every once in a while -- when traveling, for example, getting purposefully lost is often the best way to see a city! But when doing science, a loss of context is unacceptable. PhyloWidget has two features to avoid this problem. First, there is a minimum zoom level, so that you cannot zoom out to infinity. Second, there is a "Zoom to Full" function which will always bring the entire tree back into view: Power user tip: The first tip is that you can use the keyboard to change the active tool. Just use the key indicated by the dock item; in this case, "s" for Scroll, and "z" for Zoom.

Also useful: Try holding down the Ctrl key while using the pan and/or zoom tools. This causes the tool to enter into "flyby" mode, which can be more efficient for some uses.

Wait, there's one more!: At any time, just RIGHT-click and drag to scroll the tree, even if a different tool is currently selected. Convenient, eh?

Created with Processing.