Curve-fitting doesn't give strong R's; forper capita income (purchasing power parity) vs absolute coastline length or coastline per area, there's no linear relationship > 0.19.
However, average per capita income for the 138 countries I had both coastline and PCI data on $13,562, vs $9,040 for those with no coastline that I had PCI data on. No surprise.
Though Liechtenstein is not included in this analysis, it is one of two doubly-landlocked countries (the other being Uzbekistan); Liechteinstein is typically ranked first in per capita income rankings, so geography is not destiny.
A study of the geographic forms in cartography
7 hours ago