GeoServer 2.2

What's new in this version:

Referencing:
- NTv2 and NADCon Support allows for datum transformations with cm level precision (instead of the usual 4m, when all goes well). Both will activate only if the grid files are present in the data dir, so by default the mere presence of the method is harmless, but generally speaking this is very good news for whoever needs to increase reprojection accuracy.
- Continued work for supporting high accuracy datum transformations that now allow for user defined transformations supplied via WKT.
- A new reprojection console allows users to interactively test transformations of points and other geometries back and forth between the chosen CRS, and also to verify the transformation method used matches the user expectations.
- Better support for un-referenced data with the new EPSG:40400 code that identifies a coordinate system made up of a generic 2D Cartesian plane. As well as support for EPSG:102113 as an alias for Web Mercator.

Data access:
- Database-level security implements the ability to use DBMS session startup and teardown scripts to alter user access the database during a specific request while falling back on connection pooling when the request is complete. Thanks to Astrium GEO-Information Services for sponsoring GeoSolutions to make this improvement.
- Sorting and paging is now available in all WFS versions (in 1.0 and 1.1 as a vendor param) via the sortBy and startIndex/maxFeature parameters.
- A new lenient capabilities mode that allows the GeoServer capabilities documents to remain functioning despite the presence of misconfigured layers.
- A new experimental OGR data store provides access to a rich set of readable formats without needing special bridge libraries.
- The image collection coverage store allows users to serve un-referenced data through WMS using image/pixel space as the coordinate system. Thanks to SFMTA for sponsoring OpenGeo to complete this work.
- Application schema support has performance, stability, and functional improvements including reduced memory footprint, SQL joining support for more efficient queries of complex information models, support for WMS, and support for GML 3.2 application schemas.
- This work was funded through AuScope by the Australian Government.
- BigTiff support has received some performance and scalability improvements courtesy of upgrade to imageio-ext 1.1.5.

Security:
- A major retrofit of the GeoServer security subsystem adding support for a number of new authentication mechanisms including LDAP, digest and X.509 certificate authentication, and more. These improvements also includes the addition of user groups.

Web Feature Source (WFS):
- Support for WFS 2.0 adds some interesting new capabilities to the WFS protocol such as paging, stored queries, and extended operators.
- Along with WFS 2.0 comes support for GML 3.2.

Web Map Service (WMS):
- Support for additional dimensions brings time and elevation support to both vector and raster data. And, with support for time, comes support for animation in WMS.
- Rendering transformations provide a bridge between WPS and WMS and allow for very powerful visualization capabilities for processing through normal WMS.
- Support for 8-bit PNG output with transparency resulting in a nice tradeoff of performance and appealing visualization. Special thanks to Andrea for this new feature.

Web Processing Service (WPS):
- New WPS features include support for asynchronous process execution and a variety of new processes.

Virtual Services:
- Virtual services allow GeoServer to support the notion of multitenancy, enabling a single GeoServer instance to publish multiple service endpoints.
- Workspace local settings allow for specifying service settings such as contact information, proxy settings, and output format settings on a per workspace basis.
- Styles and layer groups can also now be defined on a per workspace basis.

GeoWebCache:
- A GeoWebCache configuration GUI is now available directly from within the GeoServer web admin interface, including: the ability to define new grid sets, specify which layers to cache, seed or truncate the cache, and more.