Subscribe: Comments on iPhylo: Visualising very big trees, Part II
http://iphylo.blogspot.com/feeds/6581774564210673187/comments/default
Added By: Feedage Forager Feedage Grade B rated
Language: English
Tags:
big trees  big  bit gap  bitmap  curiosity generate  equivalent zooming  firstly bit  fisheye  imagemap  maps  tree  trees  wanting  zooming 
Rate this Feed
Rate this feedRate this feedRate this feedRate this feedRate this feed
Rate this feed 1 starRate this feed 2 starRate this feed 3 starRate this feed 4 starRate this feed 5 star

Comments (0)

Feed Details and Statistics Feed Statistics
Preview: Comments on iPhylo: Visualising very big trees, Part II

Comments on iPhylo: Visualising very big trees, Part II





Updated: 2014-04-24T08:06:22.899+01:00

 



Firstly, there's a bit of a gap between what I'd l...

2007-08-04T22:12:00.000+01:00

Firstly, there's a bit of a gap between what I'd like to do and what the first experiment achieves. Click and reload is rather like zoom I agree. At this stage I'm exploring what is doable (by me).

The reason for being able to see the entire picture while at the same time zoomed in on one part is to maintain a sense of context, and my impression from the computer science literature is that usability studies suggest this matters (I'll try and dig up some references for you).

Regarding fisheye, the issue is likely to be one of scalability. The Dogo example (and the Mac OS X Dock) are tiny examples compared to a tree with 1000s of nodes. To do fish eye effectively I think you'd need to either have the tree in memory (which programs such as Dendroscopecan do)
), or really fast access to a server that would return new co-ordinates for each transformation -- neither of which seems easy to do for big trees over the web. One strategy might be to use a simpler transformation, such as bifocal visualisation (see, for example, The Bifocal Tree: a Technique for the Visualization of Hierarchical Information Structures).

Regarding the image maps, these are generated using a C++ program for parsing and drawing trees (based on code I use in TreeView X), then I use ImageMagick to convert the output to a bitmap. The C++ program also generates the image maps.

However, this evening I've abandoned image maps in favour of DIVs, because I can now show the user where they are in the tree when they click (I hope to get this next version up online later this week).



Out of curiosity, what are you using to generate y...

2007-08-04T21:12:00.000+01:00

Out of curiosity, what are you using to generate your imagemaps? I muck around with MapServer, which has a pretty good imagemap generator (see: HERE). It's entirely possible that this could be kludged to pull data from a backend & overlay the imagemap on pre-existing bitmap trees.



Now I am starting to appreciate what you're wantin...

2007-08-04T20:58:00.000+01:00

Now I am starting to appreciate what you're wanting to do. But, I'm still not convinced that panning and zooming is a problem so perhaps I need to have it better explained. What is the value in being able to simultaneously see a large portion of a tree while zoomed into a specific branch? I assumed the cognitive significance of wanting to see more detail is to temporarily push aside the big picture. Isn't your bitmap-based solution of clicks & page reloads equivalent to zooming in where the browser back button is equivalent to zooming out? You can however implement some AJAX without any great difficulty to expand/contract branches with onclick events or to also make use of the fisheye zoom (e.g. the Dojo toolkit: http://dojotoolkit.org/demos)