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The wcts (Web-Coordinate-Transformation-Service) package contains the deegree implementation of the wcts described in
the draft version (0.4.0) of the ogc.
(Partly quoted from the specification document 07-055-r1)
Introduction:
A Web Coordinate Transformation Service (WCTS), can be used by geospatial applications and other services to transform
geospatial data from one reference system into another.
Geospatial data is often stored in different coordinate reference systems (CRSs). To use together data stored in
different CRSs, such data must be transformed into the same CRS. Not all applications or services are capable of
performing such transformations. The deegree-WCTS is an implementation of the OGC Web Service interface. This is a type
of interface to a service that performs coordinate transformations. Such transformations include all the types of
coordinate operations, including both ―transformations and ―conversions
The deegree-WCTS can handle inputs of digital features (and will in the future be able to handle coverages) in
one CRS and outputs the same features in a different CRS. The service inputs include identifications of the input and
output CRSs, and optionally the coordinate transformation between these CRSs, the latter is not yet implemented.
This WCTS interface specifies five operations that can be requested by a client and performed by a WCTS server.
Those operations are:
- Transform (required implementation) – This operation allows a client to request transformation of the
coordinates in a specified set of features, and to receive back the transformed features. This operation allows the
client to identify the CRS of the input features and the desired CRS of the output features. Each feature can be a
single feature, a feature collection containing multiple features, and in the future a coverage
- GetCapabilities (required implementation) – This operation allows a client to request and receive back a
service metadata (or Capabilities) document that describes the abilities of the specific server implementation.
- IsTransformable (optional implementation) – This operation allows a client to ask a server if it can perform
any coordinate transformation from one identified CRS into another. This operation also allows the client to ask if
this transformation can be performed on specified geometric primitive or (in the future) coverage types. The response
back is binary, plus problem information when the answer is false
- GetTransfomation (optional implementation) – not implemented (and probably never will be)
- GetResourceByID (optional implementation) – This operation allows a client to request and receive back
XML-encoded definitions of one or more identified abilities provided by the WCTS server. Those abilities can be
coordinate transformations, coordinate reference systems (CRSs), or operation methods.
Since the original spec does not allow the sending of inline data (encoded inside a post(soap)-xml request)
deegree supplies this possibility. Clients are allowed to send a {http://www.deegree.org/wcts}:InlineData element. In
which three kinds of data can be inserted
- gml:FeatureCollections
- gml:Geometries
- SimpleData -- a complex element which contains the attributes, 'srsDimension' and 'cs' and is expected to
hold a list of coordinates separated by the 'cs' value and tupled by the 'srsDimension'.
@author
Rutger Bezema
@author last edited by: $Author: rbezema $ @version $Revision: 6259 $, $Date: 2007-03-20 10:15:15 +0100 (Di, 20 Mrz
2007)$
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