You can always try a Java Applet. But this suggestion might be off topic!
On Wed, Nov 19, 2008 at 12:04 AM, Mark Easton [EMAIL PROTECTED]wrote:
I'd be using C++. :)
I already have a C++ application running on our gateway which deals with
grabbing data from the stations. It then passes that to a parser utility I
wrote so that would be a good place to reduce the dataset ready for a
progressive display on a flex chart.
Yep - a very interesting application!
--
*From:* flexcoders@yahoogroups.com [mailto:[EMAIL PROTECTED] *On
Behalf Of *Josh McDonald
*Sent:* Wednesday, November 19, 2008 11:34 AM
*To:* flexcoders@yahoogroups.com
*Subject:* Re: [flexcoders] Re: Creating a Chart With 50,000 Data Points
I'd look into some intermediary code to reduce your dataset, written in
something with threads (my first choice would be Java, but that's me). It
sounds like you're working on some interesting stuff Mark :)
-Josh
On Wed, Nov 19, 2008 at 6:15 AM, Mark Easton [EMAIL PROTECTED]wrote:
Thanks Brendan,
We are charting observations from a range of sensors and contact inputs.
The contact inputs are a special case as they can only have 1 or 0 values.
But the sensors include temperature, current, voltage, light, humidity,
vibration, motion, gps velocity, gps location, wind speed, wind direction
etc.
The client does like the the charting features so he wants all of the flex
charting cool stuff as well as the ability to see these charts.
But that does not mean that I cant look at a combination of approaches.
Its a good idea to look at coding a custom chart, and one I will look at
closely.
Yes I was thinking along the lines of having 2000 plot points. So in the
case of a 3 month graph I would start with 120,000 points and need to reduce
that to 2000.
Cheers,
Mark
--
*From:* flexcoders@yahoogroups.com [mailto:[EMAIL PROTECTED] *On
Behalf Of *Brendan Meutzner
*Sent:* Wednesday, November 19, 2008 8:51 AM
*To:* flexcoders@yahoogroups.com
*Subject:* Re: [flexcoders] Re: Creating a Chart With 50,000 Data Points
What kind of charts are you displaying? I've had amazing success with
scrapping the charting framework all together and simply drawing the chart
programmatically. Yes, it's a bit more work, and yes it's only feasible if
you don't really need a lot of the charting features that come in the
framework. However, the performance difference is huge.
The project I applied this on was for financial stock data, and using a
custom drawn chart I mention above, along with the concept someone else
mentioned by only showing the n-th datapoint interval depending on the
overall range being displayed worked quite well. You're able to keep a
consistent number of plot points (I've found 500-750 performs best) no
matter what the overall range of data you're displaying. I say 500-750
performs best as I also had a horizontal axis slider which allowed for
constantly updating data in the chart.
Brendan
On Tue, Nov 18, 2008 at 1:27 PM, jim.abbott45 [EMAIL PROTECTED]wrote:
50,000? LOL. ;-)
On a more serious note, I have to agree with Fotis and Ricky that 50K
data points is too many, both from a (Flash 9 VM at least) performance
perspective and probably also from an Information Visualization
perspective (unless, maybe, your users have 300 dpi monitors).
There are several standard interaction design and information
visualization techniques which may be useful to you . . .
1) Aggregation (as already suggested, take 'N' data points, average
them, and then only display the average value).
2) Filtering (by sliders on an axis, by date/time, by structured or
open-ended queries, ...)
3) Progressive rendering (sample the entire data set at intervals of
'N', render those points, then go back and get the data which is
mid-point between the original points, add the new points to the
curve, repeat until desired resolution obtained--or on user demand)
4) Non-linear zooming (like idea 1), but allow user to zoom in on a
section of the curve, when they do, add the additional data points to
the curve for the zoomed-in region)
On a more pragmatic note, you certainly _can_ plot more than 2,000
points. For example, I've personally used Flex to create charts with
over 14,000 points in them, so I know that at least that number is
definitely *possible*. However, the overall rendering time was (as I
recall) over 3 minutes long. More troubling was the fact that the
entire Flex UI become very sluggish once a chart that large was
displayed. I've seen good chart rendering speed ( ~= 2S ) and no UI
sluggishness, up to about 1500 points. I've also been able to render
up to 6,000 points, but it took about 10S for the rendering and the UI
started to become sluggish. From your posting, it sounds like you're
not seeing those rendering speeds. I'd recommend that you experiment
with how you are using the
