This is an important and useful release as far as I'm concerned, but hopefully not a big change for users:
I have added an Interface class to represent the entire OpenGIS specification for geospatial features. I have also implemented classes for MySQL, PostGIS, and a strictly PHP-based class to handle basic manipulations and calculations.
This differs from the previous implementation, which had a sorta hackneyed, as-needed pile of function definitions. It was challenging and messy to draw calculations between different sources of GIS info (e.g. a point that represents the currently-logged-in user, and an area represented in a database). Now you can use the PHP-based and SQL-based backends interchangeably.
It was also not possible to tell what was working and what wasn't. How were we ever going to know which functions we can and call from the spec? Now you can use any of them; and you'll get back something helpful or an "unimplemented" error.
Right now, both implementations continue to exist, but I will be phasing out the geo() function and its related backend handlers in the next release or two, and other module developers are encouraged to do the same.
Also: