First off, you get reduced code duplication as the top constructor is chained to the second - passing in a 0 for the altitude parameter; the other passed in parameters are passed in to the chained constructor from the values used in the constructor itself (the distance and angle parameters). The reduced duplication is in the fact that the second constructor is the one doing the initialization and it is not duplicated in the first constructor.

The benefit is also that you now have overloaded the constructor such that the altitude parameter is optional and will default to 0 if not supplied.

The second constructor is chained to a parameterless constructor that you have not shown in your example. This one may very well initialized other parts of the class - initialization that is not repeated elsewhere.

would calling either constructor (and passing in relevant parameters) have the same result?

Sure. But this is some nice syntactic sugar - makes the code easy to read and short.

First off, you get reduced code duplication as the top constructor is chained to the second - passing in a 0 for the altitude parameter; the other passed in parameters are passed in to the chained constructor from the values used in the constructor itself (the distance and angle parameters). The reduced duplication is in the fact that the second constructor is the one doing the initialization and it is not duplicated in the first constructor.

Another benefit is that you now have overloaded the constructor such that the altitude parameter is optional and will default to 0 if not supplied.

The second constructor is chained to a parameterless constructor that you have not shown in your example. This one may very well initialized other parts of the class - initialization that is not repeated elsewhere.

would calling either constructor (and passing in relevant parameters) have the same result?

Sure. But this is some nice syntactic sugar - makes the code easy to read and short.