Hello all: When I receive an order for a sundial from somebody who lives in a large city, rather than using the latitude and longitude coordinates of the home of the customer, I use the coordinates of the City Hall of that city. I do this because City Hall is usually located near the geographical center of the city (but not always). Once I have the hour lines calculated for this location, if I ever get another order from another customer who lives in a different part of that city, then I don't have to recalculate the hour lines. In other words, I use the same coordinates for all customers who live in the same city. My rule of thumb is that if the sundial is located within about 30 miles of it's design coordinates, then its time keeping errors are too small to be detected on my sundials.
This saves me work because I can use the same sundial design for everyone who lives in that particular city. Now I'm thinking that rather than using the coordinates of City Hall for my design calculations, that it might be better to use the center of population density instead, because accuracy would be slightly improved by using coordinates that are closer to where the people of that city live. Does this make sense? Does anybody know if maps or coordinates are available which give the location for the center of population for large cities? (Don't confuse population center with geographical center). Thanks John Carmichael Tucson Arizona
