How would you go about calculating the number (approx) of miles of road in
i] Any given city
ii] All cities on the planet?
>>7654830
1/find a way to extract the roads from your picture and represent them with the same width
2/count all the road pixels
3/use scale of map to determine the whole length
>>7654839
Unworkable.
>>7654830
look it up in your handy dandy table of road lengths.
https://en.wikipedia.org/wiki/List_of_countries_by_road_network_size
For world it is: 64,285,009 km
>>7654830
Arc length formula modified parametrically
>>7654843
That's countries, not cities. I can't see a page for cities. Anyway, I'm hoping for a rough formula rather than just the answer itself.
>>7654841
unworkable ??? What are you, 10 ? Use any fucking image processing library you moron.
>>7654853
No????
I'm not being clear enough. A rough formula for doing those things without using the internet to cheat.
>>7654856
Acquiring empirical data is not cheating.
Once you have measured road networks for enough cities, fit a curve based on relevant data (population, area, and maybe age.)
It's most likely a fractal scaling law of some coefficient to a fractional exponent; things like conductor lengths of integrated circuits and vascular networks of animals scale that way.
>>7654870
That's much better.
Let's say we know the rough population, area and length of roads in one city but don't have access to any other information. Best guess for scaling up?
>>7654890
I'd say lenght of roads is proportionnal to the surface to cover
>>7654849
you can look that up too.
>>7654890
According to a paper I found, scaling exponent's probably around the vicinity of 1.6-1.8 ish with the length scale. So I'd scale it as area^0.84
>>7654921
Brilliant, thank you.
