Treemap Color Calculation Issues

[Apps & Dev CCAC]

I entered an issue about this last week, but with no feedback on that,
I thought I may get a better response here.

Here is the link to the issue that goes into more detail with an
example:
http://code.google.com/p/google-visualization-api-issues/issues/detail?id=824&sort=-id&colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Summary%20Stars

Basically, the issue pops up whenever you have a tree map with more
than 1 level of drill down. It appears when the color value is
calculated, it calculates an average based on the child directly below
it. This works fine as long as you are only drilling down one level,
but when you have more levels, you end up calculating the color value
based on averages of averages. This leaves me with data that can vary
in color drastically based on the data included in the middle tiers.

The issue I linked to is the simplest dataset I could come up with to
show the problem. I have seen other post discussing how the color
values are calculated, but nothing discussing the legitimacy of these
calculations. Has anyone else noticed this?

Personally, I would like to have the ability to specify my own color
values. I am calculating them anyway to display to the user, so why
not just use the values I put in there. Also, it would lead to the
ability to use values other than numbers that can be averaged. For
instance, I have a treemap that I would like to make where the color
would represent percent of utilization. This value would not be
something that would make sense to be averaged with other percents on
the higher levels of the treemap. Instead, it would be a value that
would have to be calculated independently at each level.

[Apps & Dev CCAC]

There's some good discussion going on over on the issue thread linked in the above post.  Some changes have been made, but nothing that really solves my problem.  If anyone else is using the treemap, some additional thoughts and opinions would be great.

[NA]

There have been other discussion on this.  I actually am in favor of allowing the user to specify their own aggregation function for determining the color, instead of using the default "average" aggregation function.  See this discussion:

  https://groups.google.com/d/topic/google-visualization-api/YwHqHA6vRXs/discussion



I'm not aware of any changes made to the treemap, though.