Class _Coordinate

source code

             object --+            
                      |            
utils.autonode.AutoNode --+        
                          |        
             common.ASTNode --+    
                              |    
                _CoordinateLike --+
                                  |
                                 _Coordinate

Known Subclasses:

• RedshiftCoo
• , SpaceCoo
• , SpectralCoo
• , TimeCoo
• , VelocityCoo

An abstract base for coordinates.

They have an iterTransformed(convFunc) method iterating over constructor keys that have to be changed when some convFunc is applied to the coordinate. These may be multiple values when, e.g., errors are given or for geometries.

Since these only make sense together with units, some elementary unit handling is required. Since we keep the basic unit model of STC, this is a bit over-complicated.

First, for the benefit of STC-S, a method getUnitString() -> string or None is required. It should return an STC-S-legal unit string.

Second, a method getUnitArgs() -> dict or None is required. It has to return a dictionary with all unit-related constructor arguments (that's unit and velTimeUnit for the standard coordinate types). No None values are allowed; if self's units are not defined, return None.

Third, a method getUnitConverter(otherUnits) -> function or None is required. OtherUnits can be a tuple or a result of getUnitArgs. The tuple is interpreted as (baseUnit, timeUnit). The function returned must accept self's coordinate values in otherUnit and return them in self's unit(s). This is the function that iterTransformed requires.