I would expect border length scales with the square root of country area, so smaller countries have disproportionally longer borders than larger ones. There al

I would expect border length scales with the square root of country area, so smaller countries have disproportionally longer borders than larger ones. There also must be more countries smaller than the average country than there are larger ones (https://www.worldometers.info/geography/largest-countries-in-the-world/ https://www.worldometers.info/geography/largest-countries-in... confirms that. Ukraine is 45th of 223, or about 20% down.) So, I guess yours is underestimating the size. You probably get a better estimate by using the Ukraine to estimate the scaling constant (√603,550km²)÷4953km and then use a list of land areas to estimate border lengths.