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Lesson 18: Turning numbers into graphs with ASP |
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Lesson 18: Turning numbers into graphs with ASP
Summary:
Learn to display your data in a graphical way by using ASP driven charts.
Intro:
Ok so now you probably know how to get data from databases, text files, forms etc.
But when it comes to displaying that data people mostly use tables or listings.
The fact is that pure text is bit boring and
often you'll get your points across allot better with a simple graph than
with a whole page of text. There are several ways to do this, and if you can afford it
server components is probably the best way to do it.
This is because such components can generate images serverside, giving you
both a high grade of browser compatibility (no need for Java or plugins)
as well as high grade of design freedom.
But what if you can't pay up several hundred or thousands of
dollars to buy such a component? There are alternatives.
Our first approach is using images
that we resize with ASP to display bar graphs. Our second approach is
a Java applet that can display a more advanced graph, but depends on a
Java capable browser.
VBScript & image resize bar chart:
I use this approach to display some of the things I log at
haneng.com, such as page views per day, and it works good. The major
disadvantages are:
a) Little design freedom, limiting your graphs to bar charts
b) Problems when you try to print them (at least with Netscape).
The pros are:
a) High compatibility
b) Easy to make, no components etc. needed
c) Free
So how does such a bar chart look like? Under is an example:
Try inserting data into this bar chart via a form.
Click to download the source code and the applet used in this lesson
In the demo I use data from the form you submit to create the chart, but
it could be done with any data that you put in the value array. Collect
info from a database or a text file and put it into the array, and voila
you have a graph of that data.
The Java approach: a pie chart
Some time ago I discussed the problems of generating charts with
my friend Arnstein.
He was at the time attending a course at the University of
Oslo about Java, and he came up with a little applet.
The applet could take some parameters and then display that data as a pie diagram.
He gave me the source code, and after I made some modifications
it worked very well. With a Java applet you can display a wide variety
of graphs, but it requires that your visitors have a Java enabled
browser for it to work. Here's what the Java pie chart applet looks like:
This is a screenshot so all of you that don't have a Java enabled
browser can see it also. The chart displays the percentage of different
browsers used by visitors on one site.
Try inserting data into this pie chart via a form (Java needed).
You can download the pie applet and all the code used in this lesson.
The same goes for this applet as for the bar chart. You can fill the chart
with data with VBScript from any data source. And you must admit that
charts bring more life to your data. If you got other ways to make graphs with ASP
and/or got a nice and free chart applet of some kind, let me know!
HanengCharts 2.0
Do you need more than 5 parameters for the pie chart?
Need other charts?
Need to set the colors?!
Download Our Free 30 Day Trial of HanengCharts 2.0!
Where to go next:
Check out the other lessons.
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