A tile represents an elementary rectangular area that
is loaded or released when needed by the application. Tiles are managed
by an
IlvTileController.
In most cases, the tile controller will be associated
with an
IlvTiledLayer. This means that the tiles represent areas that
must be filled with graphic objects when they become visible due to
the user of the application scrolling or zooming on a view.
More sophisticated applications can use a tile controller
without attaching it to a layer, for example, to load data that is
needed to process an area that becomes visible.
For example, to define a geographic coordinate system
expressing latitude and longitude with grads, instead of degrees,
you can use the following code:
IlvAngularUnit unit = IlvAngularUnit.GRAD;
IlvGeographicCoordinateSystem gcs =
new IlvGeographicCoordinateSystem("My coordsys",
IlvHorizontalShiftDatum.WGS84,
IlvMeridian.GREENWICH,
unit,
null); // No altitude
// A transformation from WGS84 geographic coordinate system
// with degrees as unit to our own coordinate system:
IlvCoordinateTransformation ct =
IlvCoordinateTransformation.CreateTransformation(
IlvGeographicCoordinateSystem.WGS84,
gcs);
// Example of conversion.
double lambda = IlvAngularUnit.DEGREE.toRadians(-45D);
double phi = IlvAngularUnit.DEGREE.toRadians(30D);
IlvCoordinate coord = new IlvCoordinate(lambda,phi);
// Convert coordinate, letting the transformation allocate the
// result.
IlvCoordinate result = ct.transform(coord,null);
System.out.println("The expression of point 45W 30N is ");
System.out.println("x = " + coord.x + " grad");
System.out.println("y = " + coord.y + " grad");