As is seen from above, we have used the buffering mechanism provided by ASP.NET 2.0 to render the images in the page-pic.aspx. These images, however, are all generated dynamically in the server side, when a good many resources are to be consumed. On the other hand, quite a few small pictures might be repeatedly rendered since we have rasterized the output. Thus, we can find a way of optimizing this by cutting the whole map into small static ones beforehand so as to simplify the image processing on the server side and accordingly improve the performance of the system.

We can easily build a small program to generate these small pieces of pictures automatically (the source code along with this article provides such a tool program named SplitPic). Obviously, with the small pictures changed into static ones, the AjaxMethod GetMapInfo on the server side needs to be modified correspondingly. I have left out the new code, for more details please see the downloaded source code.