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“-T”, this small appendix can be found after many popular GIS-related acronym. But of course, it always means something different. Take for example GIS-T (GIS for Transportation), WFS-T (Transactional WFS) and WMS-T (WMS with time support). The world of acronyms is a fun place!

Let’s see what a WMS-T can do for us. From the WMS standard:

Some geographic information may be available at multiple times (for example, an hourly weather map). A WMS
may announce available times in its service metadata, and the GetMap operation includes a parameter for
requesting a particular time
. […] Depending on the context, time
values may appear as a single value, a list of values, or an interval, …

Currently, only Mapserver supports WMS-T but the Geoserver team is working on it.

Mapserver

MapServer 4.4 and above provides support to interpret the TIME parameter and transform the resulting values into appropriate requests.

Time attributes are specified within the metadata section:

METADATA
"wms_title" "Earthquakes"
"wms_timeextent" "2011-06-01/2011-07-01"
"wms_timeitem" "TIME"
"wms_timedefault" "2011-06-10 12:10:00"
END

Mapserver supports temporal queries for single values, multiple values, single range values or even multiple range values:

...&TIME=2011-06-10&...
...&TIME=2011-06-10, 2004-10-13, 2011-06-19&...
...&TIME=2011-06-10/2011-06-13&...
...&TIME=2011-06-10/2011-06-15, 2011-06-20/2011-06-25&...

Geoserver

GeoSolutions has developed support for TIME and ELEVATION dimensions in WMS.
There are plans to backport this feature to the stable 2.1.x series after the 2.1.1 release.

Configuration of time-enabled layers can be done via the normal user interface:

The following video by GeoSolutions demonstrates the use of Geoserver’s WMS-T:

Both server solutions seem to support only one time attribute per layer. An optional second time attribute would be nice to support datasets with start and end time like Time Manager for QGIS does.

Geoserver and Mapserver are both quite powerful but their developers pursued different goals.

To make the choice easier for you (I hope), here comes a general feature comparison:

Geoserver Mapserver
WMS both are good maybe a bit better [1]
WFS better, supports WFS-T [1] no WFS-T [1]
Technology J2EE [1] CGI [1]
Project start 2003 [1] 1996 [1]
Administration Web tool Mapfile generation can be aided by QGIS, but not comparable to Geoserver’s web admin tool
Extensibility good for Java developers [1] PHP Mapscript, good for PHP developers [1]
Cartography uses standardized SLDs powerful; styles are part of mapfile
Services one WMS/WFS/WCS service for all users [1] a mapfile means a service [1]
Querying CQL and OGC filters embedded SQL statements

New benchmarking results should be available soon [2]. Meanwhile, you might wanna watch last years results [3].

[1] http://osgeo-org.1803224.n2.nabble.com/Mapserver-vs-Geoserver-td4905798.html

[2] http://wiki.osgeo.org/wiki/Benchmarking_2010

[3] http://www.slideshare.net/gatewaygeomatics.com/wms-performance-shootout

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