Predefined Readers > The CADRG File Reader > Classes for Reading the CADRG Format
 
Classes for Reading the CADRG Format
*IlvCADRGTocReader: This class reads the table of contents of a CADRG volume.
*IlvCADRGFrameReader: This class reads a CADRG frame.
*IlvCADRGLayer: This class implements load-on-demand for the CADRG format.
IlvCADRTocReader and the CADRG Model
This class allows you to read a table of contents file (the a.toc file). It gives access to the elements of the CADRG volume according to the following object model:
*The CADRG coverages are represented by instances of the class IlvCADRGCoverage. This class stores information about a CADRG coverage as described in a CADRG table of contents.
*The CADRG frames are represented by instances of the class IlvCADRGFrame.
The following example displays the table of contents of a CADRG volume:
IlvCADRGTocReader* tocReader = new IlvCADRGTocReader(fileName);
IlUShort count;
const IlvCADRGFrame* const* frames = tocReader->getOverViewFrames(count);
for (int i = 0; i < count; i++) {
IlvMapFeatureIterator* iterator = frames[i]->makeReader();
mapLoader->load(iterator);
}
In this example, mapLoader is an instance of the IlvMapLoader class. For details about the map loader, see the section The Map Loader.
IlvCADRGFrameReader
The IlvCADRGFrameReader class allows you to read a CADRG frame directly. It implements the IlvMapFeatureIterator interface.
You can create an IlvCADRGFrameReader object in one of the following ways:
*By calling the makeReader method with the name of the frame to be read. See the above example.
*By providing the name of the frame to be read to the class constructor.
This class returns a map feature for each CADRG subframe (a complete CADRG frame is made up of 36 subframes, 6 by 6). The geometry of these subframes is an IlvMapImage object. The map features have no attributes. The default renderer is an IlvDefaultImageRenderer object.
Note: This renderer is not able to reproject images.
IlvCADRGLayer
This class implements load-on-demand for a CADRG coverage. It is created from an instance of the IlvCADRGCoverage class. The size of a tile corresponds to the size of a CADRG frame. This implementation of a tiled layer works exclusively with the geographic projection for the non-polar zones of CADRG. See Using Load-On-Demand.

Version 5.7
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