Package com.luciad.format.gdf

Class TLcdGDFModelDecoder

java.lang.Object
com.luciad.format.gdf.TLcdGDFModelDecoder
All Implemented Interfaces:
ILcdInputStreamFactoryCapable, ILcdModelDecoder
@LcdService(service=ILcdModelDecoder.class, priority=20000) public class TLcdGDFModelDecoder extends Object implements ILcdModelDecoder, ILcdInputStreamFactoryCapable
This ILcdModelDecoder decodes Geographic Data Files (GDF standard).

Input

File Required Entry point Description
*.gdf x x
 Main file containing the data
*.gdf.gz
Compressed main file containing the data
*.gdf.zip
Compressed main file containing the data

Supported transfer protocols

  • This model decoder supports all transfer protocols that are supported by the ILcdInputStreamFactory of this decoder.

Model structure

The models returned by this decoder are hierarchically structured, corresponding to the structure of the GDF data: each returned model is a TLcdModelList, representing a GDF dataset. This dataset contains a number of GDF layers (which are also TLcdModelList objects and should not be confused with LuciadLightspeed layers), each having a number of GDF sections. These sections are ILcd2DBoundsIndexedModel objects, containing the actual GDF features.

On each level (dataset, layer, section), the model has a corresponding model descriptor, containing information that is specific to that level (see the GDF specification and the documentation of the GDF model descriptors).

Model descriptor

  • All models returned by this model decoder have a TLcdGDFDatasetModelDescriptor.

Model reference

    Model elements

    • Models decoded by this model decoder will only contain ILcdGDFFeature objects (ILcdGDFPointFeature, ILcdGDFLineFeature, ILcdGDFAreaFeature and ILcdGDFComplexFeature). All other supported records in the table above are accessible via these features or via the model descriptors.
    • All domain objects implement the ILcdDataObject interface, providing access to the object's type, but since GDF does not define the attributes that can occur within a feature class, the data types do not expose any properties.

    Sample code

    
 ILcdModelDecoder decoder = new TLcdGDFModelDecoder();
 ILcdModel model = decoder.decode( "streets.gdf" );

    Thread safety

    • The decoding of models is thread-safe, as long as no properties are changed during the decoding.
    • The decoded models are thread-safe for read access.

    Supported versions and specifications

    • The current implementation is based on, and compatible with version 3.0 of the GDF specification (CEN TC278, October 1995), but some of the modifications made in version 4.0 (ISO standard 14825) are already incorporated in the package.
    The following GDF record types are currently supported:

    GDF record type Decoded object (or object containing the record data)
    Dataset Header Record TLcdGDFDatasetModelDescriptor
    Attribute Definition Record TLcdGDFAttributeType
    Default Attribute Value Record TLcdGDFAttributeType
    Section Header Record TLcdGDFSectionModelDescriptor
    XY-coordinates Record
    Node Record
    Edge Record
    Face Record
    Point Feature Record ILcdGDFPointFeature
    Line Feature Record ILcdGDFLineFeature
    Area Feature Record ILcdGDFAreaFeature
    Complex Feature Record ILcdGDFComplexFeature
    Text Record ILcdGDFText
    Time Domain Record ILcdGDFTimeDomain
    Attribute Record ILcdGDFAttribute
    Conversion Record
    Relationship Record ILcdGDFRelationship
Since:
5.1

  • Constructor Details

    • TLcdGDFModelDecoder

      public TLcdGDFModelDecoder()

  • Method Details

    • setInputStreamFactory

      public void setInputStreamFactory(ILcdInputStreamFactory aInputStreamFactory)
      Sets the factory that will create input streams from which models can be decoded.
      Specified by:
      setInputStreamFactory in interface ILcdInputStreamFactoryCapable
      Parameters:
      aInputStreamFactory - the factory that creates an input stream based on a source name.
      See Also:

    • getInputStreamFactory

      public ILcdInputStreamFactory getInputStreamFactory()
      Returns the factory that is used to create input streams from which models are decoded.
      Specified by:
      getInputStreamFactory in interface ILcdInputStreamFactoryCapable
      Returns:
      the factory that is used to create input streams from which models are decoded.
      See Also:

    • setFeatureFilter

      public void setFeatureFilter(ILcdFilter aFeatureFilter)
      Sets a filter to select which features will be added to the decoded models and which not. The filter influences only which features will be directly contained in the models. Features which are filtered can still be present in the model via a reference from another feature (e.g. a road element that has been filtered can still be present via a complex feature from which it is part of).
      Parameters:
      aFeatureFilter - the filter to apply, or null if no filter should be used.
      See Also:

    • getFeatureFilter

      public ILcdFilter getFeatureFilter()
      Returns the feature filter used in this model decoder, or null if none is used.
      Returns:
      the feature filter used in this model decoder, or null if none is used.
      See Also:

    • setFeatureThemeMap

      public void setFeatureThemeMap(ILcdGDFFeatureThemeMap aFeatureThemeMap)
      Sets the ILcdGDFFeatureThemeMap to be used by this decoder. A model is created per theme in the feature theme map - and all features will be put in the appropriate model, according to the feature theme map. If null, all features will be put in one model. By default, the TLcdGDFDefaultFeatureThemeMap is used.
      Parameters:
      aFeatureThemeMap - the ILcdGDFFeatureThemeMap that is to be used by this decoder.
      See Also:

    • getFeatureThemeMap

      public ILcdGDFFeatureThemeMap getFeatureThemeMap()
      Returns the ILcdGDFFeatureThemeMap used by this decoder.
      Returns:
      the ILcdGDFFeatureThemeMap used by this decoder.
      See Also:

    • setDecodeZCoordinate

      public void setDecodeZCoordinate(boolean aDecodeZCoordinate)
      Sets a flag indicating whether the Z value of coordinates should be taken into account or not. Setting this flag to false will result in a slightly better memory usage.

      The default value is false.

      Parameters:
      aDecodeZCoordinate - boolean indicating whether the Z value of coordinates should be taken into account or not.

    • isDecodeZCoordinate

      public boolean isDecodeZCoordinate()
      Returns true if the z coordinate decoding flag is set, falseotherwise.
      Returns:
      true if the z coordinate decoding flag is set, falseotherwise.

    • setDecodeAttributes

      public void setDecodeAttributes(boolean aDecodeAttributes)
      Sets a flag indicating whether attributes should be decoded or not. Setting this flag to false will result in a slightly faster decoding and will require less memory, but not all information (e.g. road classes, names, ...) will be available in the model.

      The default value is true.

      Parameters:
      aDecodeAttributes - boolean indicating whether to decode attributes or not.

    • isDecodeAttributes

      public boolean isDecodeAttributes()
      Returns true if the attribute decoding flag is set, falseotherwise.
      Returns:
      true if the attribute decoding flag is set, falseotherwise.

    • setDecodeRelationships

      public void setDecodeRelationships(boolean aDecodeRelationships)
      Sets a flag indicating whether relationships should be decoded or not. Setting this flag to false will result in a slightly faster decoding and will require less memory, but not all information (e.g. turn restrictions) will be available in the model.

      The default value is true.

      Parameters:
      aDecodeRelationships - boolean indicating whether to decode relationships or not.

    • isDecodeRelationships

      public boolean isDecodeRelationships()
      Returns true if the relationship decoding flag is set, falseotherwise.
      Returns:
      true if the relationship decoding flag is set, falseotherwise.

    • setDecodeComplexFeatures

      public void setDecodeComplexFeatures(boolean aDecodeComplexFeatures)
      Sets a flag indicating whether complex features should be decoded or not. Setting this flag to false will result in a slightly faster decoding and will require less memory. All features constituting a complex feature will be available in the model, but the complex feature itself will not.

      The default value is true.

      Parameters:
      aDecodeComplexFeatures - boolean indicating whether to decode complex features or not.

    • isDecodeComplexFeatures

      public boolean isDecodeComplexFeatures()
      Returns true if the complex features decoding flag is set, falseotherwise.
      Returns:
      true if the complex features decoding flag is set, falseotherwise.

    • setTextTypeCodes

      public void setTextTypeCodes(String[] aTextTypeCodes)
      Sets the array of type codes whose attribute value is a pointer to a text record.

      The default list of type codes is based on the GDF 4 specification (ISO/DIS 14825 p333):

      Description Attribute Type Code
      Official Name Prefix OX
      Official Name Text ON
      Alternate Name Text AN
      Multi-media Attachment Name MN
      Directional Prefix DP
      Street Type Prefix SX
      Official Street Name Text OF
      Alternate Street Name TExt AL
      Street Type Suffix ST
      Directional Suffix DS
      Pronunciation PO
      Exit Number EN
      Route Number RN
      Route Number on Sign RX
      Building Class Name BC
      Destination Location DL
      Other Textual Content on Traffic Sign CT
      Brand Name BA
      Place Name PE
      Street Name SN
      Telefax Number TX
      Telephone Number TL
      Parameters:
      aTextTypeCodes - array of type codes whose attribute value is a pointer to a text record.

    • getTextTypeCodes

      public String[] getTextTypeCodes()
      Returns the list of type codes whose attribute value is a pointer to a name record.
      Returns:
      the list of type codes whose attribute value is a pointer to a name record.

    • setTimeDomainTypeCodes

      public void setTimeDomainTypeCodes(String[] aTimeDomainTypeCodes)
      Sets the array of type codes whose attribute value is a pointer to a time domain record.

      The default list of type codes is based on the GDF 4 specification (ISO/DIS 14825 p333):

      Description Attribute Type Code
      Validity Period VP
      Opening Record OP
      Parameters:
      aTimeDomainTypeCodes - array of type codes whose attribute value is a pointer to a time domain record.

    • getTimeDomainTypeCodes

      public String[] getTimeDomainTypeCodes()
      Returns the list of type codes whose attribute value is a pointer to a time domain record.
      Returns:
      the list of type codes whose attribute value is a pointer to a time domain record.

    • getDefaultExtension

      public String getDefaultExtension()
      Returns the default extension for GDF files.
      Returns:
      "gdf".

    • getDisplayName

      public String getDisplayName()
      Description copied from interface: ILcdModelDecoder
      Returns a short, displayable name for the format that is decoded by this ILcdModelDecoder.
      Specified by:
      getDisplayName in interface ILcdModelDecoder
      Returns:
      the displayable name of this ILcdModelDecoder.

    • canDecodeSource

      public boolean canDecodeSource(String aSourceAsString)
      Description copied from interface: ILcdModelDecoder
      Checks whether this model decoder can decode the specified data source. It is acceptable for this method to return true for a source name while decode throws an exception for that same source name.

      For performance reasons, we strongly recommend that this will only be a simple test. For example: check the file extension of a file, but not that the file exists or contains expected content.

      Specified by:
      canDecodeSource in interface ILcdModelDecoder
      Parameters:
      aSourceAsString - the data source to be verified; typically a file name or a URL.
      Returns:
      true if this decoder can likely decode the data specified by the source name, false otherwise.
      See Also:

    • decode

      public ILcdModel decode(String aSourceName) throws IOException
      Description copied from interface: ILcdModelDecoder
      Creates a new model from the given data source.
      Specified by:
      decode in interface ILcdModelDecoder
      Parameters:
      aSourceName - the data source to be decoded; typically a file name or a URL.
      Returns:
      A model containing the decoded data. While null is allowed, implementors are advised to throw an error instead.
      Throws:
      IOException - for any exceptions caused by IO problems or invalid data. Since decoding invalid data almost always results in RunTimeExceptions (NullPointerException, IndexOutOfBoundsException, IllegalArgumentException, ...) on unexpected places, implementations are advised to catch RuntimeExceptions in their decode() method, and wrap them into an IOException, as illustrated in the code snippet below. 
      
   public ILcdModel decode( String aSourceName ) throws IOException {
      try (InputStream input = fInputStreamFactory.createInputStream(aSourceName)) {
         // Perform decoding ...
      } catch (RuntimeException e) {
         throw new IOException(e);
      }
   }
      See Also: