使用PHP 繪製圖表
如果你是GD function 又是演算法的高手，我會建議你自己寫php 的code，如果不是的話我實在建議你用現有的繪圖元件。
JpGraph
The library can be used to create numerous types of graphs either on-line or written to a file.JpGraph makes it easy to draw both "quick and dirty"graphs with a minimum of code as well as complex graphs which requires a very fine grained control.
JpGraph
可繪製Line,Bar,Pie (2D &3D),Ring,Field,Splines,Geo Maps,Stock,Polar,adar,Gantt,Impuls,Error,Scatter,Balloon,Canvas,Antispam,Odometer,Windrose, Barcodes
介紹：JpGraph -Features
Graphviz
Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks.Automatic graph drawing has many important applications in software engineering,database and web design,networking,and in visual interfaces for many other domains.
Graphviz
可繪製cluster,crazy,datastruct,fsm,hello,profile,sdh,switch,unix,world,ER,fdpclust,inet,process,softmaint,transparency
介紹：
http://www.graphviz.org/Gallery.php
springgraph
http://www.chaosreigns.com/code/springgraph/
GraPHPite
GraPHPite
