I need a control to add data trending to my application. Is anything available or do I need to use a graphing control and add my own trending features?
+2
A:
Trending is typically an included feature in 3rd party charting components (at least the ones i've seen) but it might be called something else such as linear regression or possiblly something like "least squares*." You should definitely not need to roll your own, unless you think it would be fun. ;-)
Google-ing for "Delphi Chart Regression" will turn up some interesting links.
(* Least squares is typically the method used to establish a trend line from a data set.)
Paul Sasik
2010-07-22 20:32:26
Thanks for the quick reply.Looking thru the Google search most everything appears too complicated for my use. What I need is a chart that plots disk usage by day with a trend line showing the approximate day you will run out of disk space. Any quick and easy you are aware of?
Steve
2010-07-22 21:08:16
Quick and easy usually means using 3rd party components. And even though they look complicated, it's nothing compared to trying to create your own charting/regression control. Now, you have a pretty specific requirement. Have you looked for 3rd party applications that do that kind of analysis for you?
Paul Sasik
2010-07-22 21:46:18
Not that I can decypher from their descriptions ;>)
Steve
2010-07-22 22:01:16
Disk usage does not require linear regression. Ouch. Linear regression is great for correllations between data, and in particular gets a lot of use in analytical chemistry and scientific studies. -1 for conflating your answer with a bunch of not-relevant stuff.
Warren P
2010-07-23 16:24:43
@Warren: I was trying to expand the conversation and help a charting noob Google for libraries more effectively. Besides, what Steve meant by "disk usage" was "use of disk space" which is a concept well suited for trend analysis. I would appreciate it if you read Steve's question, my answer and our subsequent discussion more closely and then removed your down vote. Thx
Paul Sasik
2010-07-23 16:57:02
It's locked. I can't
Warren P
2010-07-23 17:13:57
Try now. I did some formatting edits which should unlock the votes for some period of time. And a sincere thank you for your reconsideration.
Paul Sasik
2010-07-23 19:56:41
+1
A:
In your shoes, I'd use the stats and charting tools from http://www.lohninger.com/delfcomp.html. It may be a bit more low-level than you want, but I've been very happy with this guys tools (which are reasonably priced, IMO, and, as I recall, can be downloaded for free on a trial basis...)
Check out the curvefit example (comes with an exe demo so no compiling or installing is necessary) here: http://www.lohninger.com/examples_part1.html It'll show you the kinds of charting as well as curve fitting. It's very instructive.
Robert Frank
2010-07-23 01:20:17
Curve fitting is cool. But does the user need to do it? Where did people get the idea? Trending is not always implying linear regression, curve fitting, calibration equations, etc.
Warren P
2010-07-23 16:35:05
+1
A:
Look for TChart component on your component palette. If your Delphi version has it, then look for demo that uses it.
avra
2010-07-23 10:58:10
TChart does not include source code, which might not matter to some people, but is a reason not to use it, if you're me.
Warren P
2010-07-23 16:27:07
A:
Try JvChart from the JEDI JVCL. If you don't like it, let me know, because I wrote most of it, and I always like to know what people think. It can do static and scrolling displays, and it is very easy to add a few lines and plot some data. A demo app is included in the JVCL\examples\JvChart folder.
There is also TJvSimScope, which is like an oscilloscope and is optimal for fast-scrolling charts showing data which changes on a per-second basis.
JVCL is open source and free
Warren P
2010-07-23 16:25:19