I saw your post from 2008 about wanting to easily update multiple excel charts or graphs without having to change the SourceData for each graph every day or week (however frequent the time-scale happens to be).
If this subject is still of any slightest interest, please let me know.
I use scores of 12-week graphs that must update every week (adding the new figures each week and discarding the figures from 13 weeks ago). Manually, this could be VERY time consuming.
I just conceived, tested and now use a tamper-proof and simple solution that works beautifully and automatically. I just implemented this in my own graphs and pie charts, et al. The charts update as soon as the most current figures are entered.
It is a comparatively simple and is a clever use of embedding the functions "VLOOKUP()" and "NOW()".
Because it uses "NOW()", the right-hand side of the chart (if you want a line or bar chart) is always the most current data.
To do this, you create what I call a "mirror worksheet". This mirrors the worksheet containing that contains the SourceData. Because the mirror uses "NOW()" the results in the "mirror worksheet" are constantly updating (on their own) to the newest data on the SourceData sheet.
The "VLOOKUP()" function is used to create the mirror and "NOW()" is used to be constantly looking up the most current SourceData information based on your computer clock.
The beauty is that the chart's data source never has to change because the mirror constantly reflects only the most current information on its own, based on your computer clock.
Once this is done, the mirror sheet can be HIDDEN and never touched again. The graphs will update automatically from then on and once it is set up.
Exactly how to set this up can be figured out with the above information, but I will be doing a full write-up on how to do this with more specific directions later.
Let me know if there is interest and I will hurry up with the full write-up.
Richard