Rahul Vaidya’s Blog

Generating Google Maps tiles using MapServer is not completely intuitive. For static map applications, a new tile mode has recently been created for MapServer CGI mode ( http://mapserver.org/output/tile_mode.html ).

For more dynamic mapping applications, PHP MapScript is an ideal way execute this, as it only requires a very small static component (an initial map file, which won’t even be needed when MapServer 5.4 comes). Included is a short PHP example on how do go about doing this. The PROJ.4 projection parameters included are for the Google Maps mercator projection.

The sample code includes WGS84 to Google Maps mercator projection as well as the calculation of mercator extents from Google Maps tile indices.

This example has been extended from the previous iteration to include dynamic layer generation and POINT geometry feature symbols via image files. The $phplayers variable holds layer definitions that have been queried from a database table, obtained using the getLayersForSessionID($sessionID) function. The table includes layer table name, layer geometrytype layer geometry name, and a symbol definition for the layer. For point layers, this is an image file (ie. “image.gif”), and for polygon and line layers, this is a line color (255 0 0 for red).