qtm

[mtennekes]

qtm is quite hard to reimplement due to backward compatibility. In v3 there were trillions of arguments that could be passed on, and also in v4, so quite complex to get it right.

Related to #861 : I'm not aiming for exact code translation (which is hard) but low level learning tips, that I think is also more useful from an educational point of view.

This one from #851 is working well:

qtm(World, borders = NULL) + 
    qtm(metro, symbols.size = "pop2010", 
        symbols.title.size= "Metropolitan Areas", 
        symbols.id= "name",
        format = "World")

This to do's for qtm : facets and baseman's.

Please use this issue to post examples of qtm that don't work as expected or that give a different result than in v3.