3.1.3 World or Image Coordinates

World or Image Coordinates

When we need to handle both world and image coordinates in the same way we use a special class WorldOrImageCoords . This class represents either image pixel coordinates (class ImageCoords ) or World Coordinates (class WorldCoords ). The constructor takes an instance of either of these classes and sets a flag, isWcs , to note which kind it is:

 
// constructor - initialize null coordinates 
WorldOrImageCoords(); 
 
// constructor: initialize World Coordinates 
WorldOrImageCoords(WorldCoords);
 
// constructor: initialize image pixel coords 
WorldOrImageCoords(ImageCoords);

Example:

 
WorldOrImageCoords ic1(ImageCoords(123.456, 654.321)); 
WorldOrImageCoords ic2(ImageCoords("123.456.", "654.321.")); 
cout << "these coords should be the same (or very close):" << endl 
		<< ic1 << endl 
		<< ic2 << endl; 
 
WorldOrImageCoords c1(WorldCoords(49.95096, 41.51173)); 
WorldOrImageCoords c2(WorldCoords(3, 19, 48.2304, 41, 30, 42.228)); 
WorldOrImageCoords c3(WorldCoords(HMS(3, 19, 48.2304), HMS(41, 30, 42.228))); 
WorldOrImageCoords c4(WorldCoords(HMS(c1.ra()), HMS(c1.dec()))); 
WorldOrImageCoords c5(WorldCoords("3 19 48.2304", "+41 30 42.228", 2000.0)); 
WorldOrImageCoords c6(WorldCoords("3:19:48.2304", "+41:30:42.228", 2000.0)); 
 
cout << "these coords should all be the same (or very close):" << endl 
		<< c1 << endl 
		<< c2 << endl 
		<< c3 << endl 
		<< c4 << endl 
		<< c5 << endl 
		<< c6 << endl;

See WorldOrImageCoords(3) for more details.