The IlvRasterAbstractReader class contains the
methods for all readers of raster image formats. It contains a
built-in tiling mechanism for tiling the image to be displayed.
Geo-referenced image list
The
IlvRasterAbstractReader
class is an abstract class that handles an indexed list of
geo-referenced images. Each image consists of two objects:
- The raster data (the pixel table values) that are managed by an IlvRasterMappedBuffer .
- The raster properties (color model, size, location, and so on) that are stored in an IlvRasterProperties.
Subclasses should provide a method (often called
addImage
) that creates both an
IlvRasterProperties
and an IlvRasterMappedBuffer and adds them to the
list using the
addRaster
method.
Projection transformation
The IlvRasterAbstractReader needs the
projection of the original raster and the projection to use in
the view. From these it can dynamically (on-demand) compute every
pixel visible in the tile to be loaded. Sub-classes must
implement getInternalTransformation in order to
provide the coordinate system in which the original data is
stored. As the getLowerRightCorner and getUpperLeftCorner methods return the IlvRasterProperties bounds, these bounds
must be provided in the same coordinate system.
Image metadata
Image metadata subclasses also have to implement the getProperties method to provide the IlvFeatureAttributeProperty attached to
each of the images.