The 2-axis (economic + social) 4 quadrants makes far more sense because although there is a tendency for right wing economics to follow authoritarian regimes the 2 are different dimensions. The plot helps clarify my dislike of labour, thery are more authoritarian than the Tories and closest to the BNP! Which makes sense the BNP are actually somewhat leftish when it comes to economic policy (mostly because they want to see robs hood style taxes to take prey from the rich).
For someone like me who want economic centralist/slightly right but socially liberal there are not many choices with the UK.
Always amuses me when bigots complain about the last left. Do they mean the slightly more authoritarian Labour Party, the slightly more social liberal Conservative party, both of which are actually very far right economically and socially, or do they mean a true left-economic or liberal party?
As it stands the only truely left party is the greens (ls lightly left economics and slightly liberal). There is no far left.
As to the data, it is fairly objective scale. Complete state ownership, a la communism is on the far left economically. Extreme far right economic policies appear on the right, see US main parties. Extreme authoritarian regimes,e.g. Nazis appear at the top. Of course the exact positioning of the parties has some error margin and fuzziness that is hard to convey.