A few ideas I held to while I tried to design the vis. :-
1) Allow user to get maximum information on a cursory glance.
2) Allow the more discerning user to get more information if they spend more time on this.
3) Use aspects of modelling only when necessary. Avoid additions unless they re-inforce information where needed.
4) Try NOT to make it look messy
5) Make it easy to adjust the visualisation for any given dataset (for any set of years / for any pollutant/etc.) with minimum rework
Here is a couple of quick and rough sketces I made to put down the initial concept. ( Disclaimer: I am not a good artist)
The pollutants:
These are differentiated by using different objects for each pollutant.
I allow the user to gain information about the pollutant levels at various levels of detail:
- Lowest detail: An aggregate value over each MSA, over the representative years. This is indicated by the colour of the MSA.
- Medium detail: With a little more time, the user can visit each MSA and look at the objects on the screw ( for one pollutant), to get a breakdown of approximate trend of a pollutant. For this purpose, I use data grouped into about 4 categories, depending upon the range of data available in these years.
- Highest detail: For that ocassional user interested in exact values, I provide a scale built out of a blind. For each year, the user can easily trace out the value to the scale to obtain the value in that year.
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| Lowest level of detail |
Medium level of detail |
Highest level of detail |
Adding to the above possibilities, overall information across California may be obtained via easy comparision:-
Using the colors, shapes on the approximate (tower) scales, and even tracing similar colored threads (for maxima/minima during each year).
The absolute scale on the side is varying in minimum-maximum for both pollutants. This is not exactly very clear in the visualisation, and I could not overcome that problem easily.
The visualisation model from different angles can be seen below.