Node Overlap Problem

A recent problem that has come to light involves the overlap of nodes in maps with a large number of nodes.

The problem was not immediately obvious when I was developing the node positioning function as I was testing it with chains of nodes which are relatively distributed.
But it can be clearly seen when you look at a purely heirachal map with no node chains for exampl: [Working with HTML in dreamweaver].

I considered the problem of overlap when i designed the positioning function. The possibility of overlap was the initial motivation behind succesively scaling child nodes and connecting lines. Scaling nodes in this way naturally leads to an efficient node packing in 2d space as it follows a self similar fractal pattern. +The root of the issue comes from the fact that the best solution for packing nodes mathematicaly does not result in the most readable nodes or the best user experience.

Essentially solving the problem by adjusting the scaling constant results in faster exponential scaling of child nodes, shrinkling branches and nodes. However this makes the user spend the majority of thier browsing time zooming in and out of the map having to constantly change scales to read the node text.

So what to do?
Well one solution would be to redesign the positioning function to create an auto-avoidence script that knows where its nearest nieghbour is an moves out of the way. There are a number of ways to do this in flash but all require to much of a sacrafice in control of where the node is positioned.

An alternative solution is to make a small adjustment in the positioning function to incorperate the number of children the parent of the node has and shink all sucessive braches from the node. This amounts more to dynamic scaling based on the number of siblings rather than a fully fledged avoidence script. This would require less computing power and would give a more organized structure.

In an ideal situation i could have the best of both worlds, create an efficient avoidence script that elasticly positions nodes within a set degree of separation. It would give a great organic feel to the map but may create unpredictable change to the overal structure as the node settle into place.

Im confident i can adjust the positioning script but it will have to wait iuntill i have created all the trial maps so that i can get a good feel for the typical range of map structures and asess the degree at which i will need to modify the mapping engine.

Reshaping The Direction of R & D

My primary goal in creating quantum semantic learning spaces has been to investigate how used can benefit from a carefully crated learning environment and how visual interfaces affect their learning. This has proven to be a somewhat illusive goal that in many was should be the very last thing i should really be looking at in these early stages of developing the visual mapping engine.

Instead I am going to focus on a more refined area of development that will pave the way for further investigations into how the map is used in class rooms and other learning environments. What I am going to refocus this investigation on is how to tool a mapping interface to be as user centric as possible. how to provide an intuitive set of user controls that lets the user view and manipulate media in the map as efficiently as possible. This will help ensure that the beta version is as mature as possible before I open it to general users (currently only subscribers can use the interface).

Rolling Out The Beta

The time has come for me to reluctantly roll out the first prototype for general use.
So far I have only created module maps for dreamweaver, Working with Tables, Working with Images and Working wit Text. Each map is created using the same settings for the semantic engine.

Take a look [video tutorial maps].



I decided to go for the name "video Tutorial Maps" as its a bit more descriptive of what they are and how they work than "Quantum Semantic Learning Spaces".

As I published these maps to the site one thing that became clear is a problem related to the transparencey of the swf. Given the detail of the graphic in a map it is important to make the content have a high level of contrast with the background of the map. This is important not only for readability but also as a reference point for users when dragging the map.
Initially I set the swf to transparent using wmode the embedding settings so that the gradient background of the web page design I have would show through. This presented some isssues with dragging but they were solved in this prototype.

[ziggy flash prototype]
This maps works perfectly as long as two things are true.
1. you are using internet explorer
2. You have a SXGA resolution monitor.

the resolution has to be high enough so that scroll bars do not appear on the browser window otherwise the windwo will move up and down when you use the scroll wheel to zoom.

The browser problem is a bug with firewox and opera. Essentially the way Firefox anf opera handle embedded swf file that are set to transparent is different from internet explorer. When in transparent mode mouse events do no propgate down to the level of swf file. Since ziggy is programmed using actionscript 3.0 and it object oriented "language" uses event listeners as its primary method of capturing mouse events. The mouse a events such as doublke click, or scroll are not setected by the swf when viewd in these browsers.

There are a couple of workarounds for these browser bugs however given the debvelopment I plan to do on the interface i hardly seems an appropriot use of time to chase browser bugs. So my solution has been to simply change the settings so that the swf is no longer in traqnsparent mode but rather has a fixed color background.
After a few different grays i decided on a blue to match the page baqckground. but of course that can be changed if needed.

Here is some more information on [video tutorial maps]