Technical Information

This site is built using Extensible Markup Language (XML) technology. What this means is that the site is not created with HTML directly. Instead, these pages are created from templates using a set of special markup tags. The page templates are then transformed to these HTML pages using a stylesheet. This transformation is via Extensible Stylesheet Language Transformation (XSLT). The stylesheet is written in Extensible Stylesheet Language (XSL). The XSLT process takes the page templates (in XML) and uses transformation rules in the stylesheet to create these pages in HTML. These HTML pages can then be viewed with browsers such as Internet Explorer, Netscape Navigator, Mozilla, Opera, etc.

The raw data for the listings in this site are stored in a relational database. A proprietary database schema is used to organize and access the data. Updates and additions are entering into this database. The relational database technology uses the Structured Query Language (SQL) to extract data from the database. The use of SQL provides a flexible and modular approach for accessing data.

The site's pages are generated with PHP running on a local server. The PHP pages are actually the product of the XSL transformation. This offers several benefits: 1) the PHP pages do not need to be hand coded 2) layout and style is consistent for all pages 3) static pages can be deployed on the public server, thereby reducing load. A 'cook' process gets a snapshot of the PHP pages and stores them as static HTML pages.

The site's build process is performed with a technology called 'ant' from the Apache Group's Jakarta project. The 'ant' tool also incorporates the XSL transformations.

Castro SF's exclusive Flash maps rely on a number of technologies. The geographical data was authored with Microsoft Visio from San Francisco Planning Department maps. Visio provides a scaled vector drawing, tagging of objects, and VBA to transform drawings to other data formats. The places in the Visio drawing are tagged to link them with the database. Information from both the drawing and the database are converted to XML. An XSL transformation merges the data and creates a number of XML coded Flash files. Finally, the XML Flash files are converted to SWF format.