Luigi Tibaldo / gammalib

Added GWcsSIN class.

In the introduction of the GSkyMap::shape() method, a change was introduced that led to writing single maps as 3D images. The code was modified so that the original behaviour of writing 2D images was recovered.

The shape() and ndim() methods allow the handling of images with more than three dimensions in GSkyMap. Now higher dimensional images are properly read and written by the class, and the shape() method allows setting of higher dimensional map parameters.

… GSkymap object. Existing pixel values are kept, any new pixel values will be set to zero. Add an appropriate unit test.

The new method stack_maps() now works on the object it is applied to instead of creating a new sky map. The reason is on the one hand semantic, as "stack_maps" is an action applied on the current object. For an object returning a skymap, the name should be something like "stacked" as the new map is a stacked version of the old one. But another reason is memory usage. The method now allocates a new memory space for the stacked map and releases the old memory once the stacking is done.

The new implementation is also more general as this method now works for both WCS and HEALPIX projections.

A unit test has been added to make sure that the maps were indeed stacked.

The operator+= and operator-= add and subtract pixel values from one map to another by bi-linearily interpolating the values in the right hand side map.

(I chose `centre` because there were more `centre` than `center`
around.)

The coding and design conventions (CDC) document was also updated.

GTestSuites
  The GTestSuites class now derives from GContainer and implements
  the usual container class methods (at(), size(), isempty(),
  set(), append(), insert(), remove(), reserve() and extend()).
  The operator[] now returns pointers to GTestSuite. The name()
  and timestamp() methods now return const references.

GTestSuite
  The GTestSuite class now derives from GBase. This implies that
  the clone() method needs to be implemented for derived classes.
  The test_assert() method now takes a const reference for the
  boolean argument. The name(), errors(), failures(), and
  timestamp() methods return const references. The obsolete
  add_test() method has been removed.

The unit tests have been updated to conform to the new interfaces.

The GSkyPixel class now handles 1D and 2D sky indices. This made the distinctive 1D and 2D methods in GSkyProjection and the derived classes obsolete. Now, all projection classes take GSkyPixel as argument.

The GSkymap class now uses the universal GSkyPixel class. Methods have been renamed consistently. An integer index is now consistently called "sky map index" and the GSkyPixel object is named a "sky map pixel". Methods operating on indices contain now "inx", method operating on sky map pixels "pix".

GSkyPixel is now able to handle both 1D and 2D sky map pixels. 1D sky map pixels behave like int or double types, and conversion from and to these types is supported. 2D sky map pixels store the X and Y component of the pixel. Methods are provided to test whether a pixel is 1D or 2D.

The GWcslib class has been renamed to GWcs for consistency with the naming convention for GammaLib base classes. All WCS implementations derive now from GWcs. The code has been adapted to this new naming convention.

The Healpix pixelisation is not a World Coordinate System projection, and to make this clear the name has been changed from GWcsHPX to GHealpix. The code has been adapted to this new naming convention.