I have been experimenting with Google charts. Are there any alternatives that are reasonably as expressive but can be installed locally on your own web server? I don't like the idea of relying on an outside entity for a feature to work. Even if it is for cost, it would be preferable. Any suggestions?
I've had some good success with flot: http://code.google.com/p/flot/
It does client-side rendering using canvas.
The Google Visualization API in no way prevents you from hosting things on your own server; the API is merely a design contract intended to provide a uniform way of representing data and visualizations. Anyone who wants to do so can create their own visualizations and data sources that conform to that API. I would suggest you reconsider, as using that API will improve compatibility and allow you to take advantage of other visualizations and other data sources that similarly conform to the API. You can host your own visualizations and your own data sources without relying on Google in any way. For more info, you may be interested in:
Don't have much experience working with either, but here are the two alternatives that come to mind:
- JFreeCharts: http://www.jfree.org/jfreechart/ (this is a Java library, not sure which language you are using)
- YUI Charts: http://developer.yahoo.com/yui/charts/ (JS-based)
There are a number of suggestions here: http://stackoverflow.com/questions/119969/javascript-chart-library
Google aside, flot seems the most popular.
If using Flash is no problem you may want to consider FusionCharts (www.fusioncharts.com). They offer a fairly rich set of charting widgets; it's a commercial library.
We've used it in some of our products, and it works well. One of their high-profile users is this federal government's site: http://it.usaspending.gov/
We've used Cewolf which is built on top of JFreechart but uses JSP's.