deegree

For this purpose the CRSProvider interface is created. It allows the CRSConfiguration to rely on a wide variety of different 'crs-definitions-formats' for example deegree-crs, wkt, proj4 (not implemented yet) or gml (not implementedj yet). The good thing is, the interface defines an export method, which can be called with a crs to receive a crs-definitions for the implementing interface, thus allowing to create an arbitrary configuration swift between the implementations.

Examples of coordinatesystems are:

• Geocentric,uses a geocentric datum)
• Geographic (coordinates are often given in degrees and use a geographic datum
• Projected, which uses a projection to map points from and to a geographic crs
• Compound, which is a geographic crs with an extra vertical 'height' axis attached to it

Although these are the most frequently used, other coordinates systems may be possible.

Because of this and because of the fact, the earth isn't a perfect sphereoid --or even a perfect ellipsoid for that matter--, there is no 'best' projection for the projection of every region on earth. Hence a lot of different mathematical projectional functions have been developed over the years. It is possible to categorise these functions into three groups:

• Cylindric projections
• Conic projections
• Azimuthal projections

(From wikipedia) Azimuthal projections have the property that directions from a central point are preserved (and hence, great circles through the central point are represented by straight lines on the map). Usually these projections also have radial symmetry in the scales and hence in the distortions: map distances from the central point are computed by a function r(d) of the true distance d, independent of the angle; correspondingly, circles with the central point as center are mapped into circles which have as center the central point on the map.

The mapping of radial lines can be visualized by imagining a plane tangent to the Earth, with the central point as tangent point.

To show a region for which the greatest extent is from east to west in the temperate zones, conic projections are usually preferable to cylindrical projections.

Normal conic projections are distinguished by the use of arcs of concentric circles for parallesl of latitude and equally spaced straight radii of these circles for meridians. The angles between the meridians on the map are smaller than the actual differences in longitude. The circular arcs may or may not be equally spaced, depending on the projections. The polyconic projections and the oblique conic projections have characteristcs different from these.

There are three important classes of conic projections:

• The equidistant
• the conformal
• the equal area

Cylindrical projections are used primarily for complete world maps, or for maps along narrow strips of a great circle arc, such as the Equator, a meridian or an oblique great circle.

The base class of all transformations is the CRSTransformation, which represents the operation of tranforming coordinates from one crs into another.

The TransformFactory tries to create the appropriate transformation(s).

It encapsulates the Jakarta log4j service, the Java 1.4 logging features and JBoss logging service.

The logging service is configured by the properties file LoggerService.properties. The most important entry is:

The log system configuration files are:

• LoggerService.properties - configures the deegree internal log system, set the property log.class to the prefered log system, this file is required.
supported log systems are:
• log4j: log.class=org.deegree.framework.log.Log4JLogger, required config file is log4j.properties
• JBoss logger: log.class=org.deegree.framework.log.JBossLogger, use %JBOSS_HOME/server/default/conf/log4j.xml to configure the log system
• Java 1.4 logging API: log.class=org.deegree.framework.log.JavaLogger, required config file is logging.properties

Note: Remove the log4j.properties file from the deegree jar or within the class path of the application if you use JBoss as your application server.

Package Specification

• Jakarta log4j

Related Documentation

• Tutorial "Short introduction to log4j" by Ceki Gülcü

Used Design Patterns

• Facade

Developer pair

• Torsten Friebe (Owner)
• N.N. (Reviewer)

Package Specification

Related Documentation

• OpenGIS Specifications
• ISO/TC 211 Specifications

Used Design Patterns

Package Specification

• OpenGIS® Specifications - OpenGIS® Catalogue Services Specification

Related Documentation

• Tutorial "deegree CS-W"

Used Design Patterns

Package Specification

• OpenGIS Specifications

Related Documentation

• Tutorial "deegree Web Coverage Server"

Used Design Patterns

• Facade

(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

1. gml:FeatureCollections
2. gml:Geometries
3. 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'.

Package Specification

• OpenGIS Specifications

Related Documentation

Used Design Patterns

Package Specification

• OpenGIS Specifications

Related Documentation

• Tutorial "deegree Web Map Server"

Used Design Patterns

Package Specification

• OpenGIS Specifications

Related Documentation

• Tutorial "deegree Web Map Server"

Used Design Patterns

It supplies all necessary methods and classes to parse owscommon 1.1.0 xml-files as well as methods to create xml representations from encapsulating java-beans.