Incorrect parameter in Figure.meca()

[maxrjones]

Description of the problem

Figure.meca defines an alias as C = offset. Based on the description of the offset parameter, I think this alias should be for the -A option in GMT's meca (https://docs.generic-mapping-tools.org/dev/supplements/seis/meca.html#a); -C is for giving a cmap for the compressive part of the beachball.

This is both a code and documentation issue, since there are these two checks for -C in kwargs (which should not be required for meca):

            # Add in plotting options, if given, otherwise add 0s
            for arg in plot_longitude, plot_latitude:
                if arg is None:
                    spec.append(0)
                else:
                    if "C" not in kwargs:
                        kwargs["C"] = True
                    spec.append(arg)

Relates to the proposed refactoring in #1002

[seisman]

GMT made some changes to the -C option recently (GenericMappingTools/gmt#4873), although it's still backward-compatible.

We should upgrade the Figure.meca() syntax to match the GMT 6.2.0 syntax.

[maxrjones]

GMT made some changes to the -C option recently (GenericMappingTools/gmt#4873), although it's still backward-compatible.

We should upgrade the Figure.meca() syntax to match the GMT 6.2.0 syntax.

Thanks for pointing this out - lesson learned to check the 'latest' documentation in addition to the 'dev' documentation before posting.