Classes for Reading the CADRG Format

Maps > Predefined Readers > The CADRG File Reader > 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 6.1