A guided tour of City

This page assumes you have the spreadsheet loaded and ready to use, so you have either printed this page out (reccomended) or you're switching windows (not so convenient).

As in all spreadsheets there are some cells for you to type in data. If Global Protection is enabled only they can be changed. If it's not on now, switch it on! And put a master copy somewhere!!
Make sure all the data cells are set to the default values before starting with a country in your universe you are most familiar with. City comes set for England 1340.
Let's start at cell B5, HEX. Here you set the size of the hexes on your map grid. The default is the old Judges Guild system, with each 25 mile across 'big' hex containing 625 one mile across 'small' hexes. If you don't have a grid, measure in squares and divide by 0.866 to convert to hexes. This is LAND, and COAST represents fishing, the number of coastal and lake hexes out to about 25 miles.
EXTRA% alters the population. '20' means 20% more people. Leave it at 0 for now.
YIELD is the variable to change for a fantasy world where, for example, priests are blessing crops or evil magicians are casting blights upon the land. CLIM would be low for a desert, high for sub-tropics.

Agricultural Tech Levels (TL) are:

  0   Nomads
  1   Farmers without Cities
  2   Ancient Farming
  3   Medieval Farming
  4   Pre-Industrial Farming
  5   Early Industrial Farming
  6   Standard Industrial Farming

Having set the above you can now adjust the 'Universal Fudge Factor' to give the Population you want in the box below. By Universal we mean just that: countries in the same Universe should have similar UFFs. If no messages appear in the 'Warnings' section then you are safe.
URBAN is a variable that allows you to change the proportion of people living in cities manually (the proportion changes with TL already). The note beside it suggests some values. At TL3 URBAN=0.9 is about as high as you can go safely.
Off to the right is a section called Land Use. The suggested percentages are taken from the Domesday Book (1086), and didn't change dramatically in England until the 20th Century, maybe 5% up for Arable and Pasture, 5% down for Woodland. Currently Woodland is 7.5%, the government proposes to double this - back to Domesday. The Veggie Factor reflects the greater food yield obtained by cultivation (the reason humans stopped hunting and became farmers). It is, like much of this sheet, a total guess! Woodland contributes a small amount from hunting (and poaching).
Hint: if you plan drastic changes to variables, set EXTRA% very low (-90?). This will prevent total confusion. You can then slowly increase population and make other adjustments.

Further down (Cell B35) is a second set of variables that relate to individual cities. You should fix the country variables above before playing with these ones.
COASTAL? asks if your citizens have fish as part of their diet. If they do, they will need less farmland.
CCOUNT splits your city into two or more nearby cities. See 'Rural Edge' below.
AR (Area Requirement) is to do with the fact that your city will have factories, offices, etc, commercial buildings that take up space but have no one living in them. The suggested values range from 'res', a largely residential town, to 'comm', a highly commercial city. Try them out and watch the 'Area of City' statistic beneath change.
Around the city live farmers producing food for the citizens. FARMLAND can be increased if the fraction of useable land is greater than the national average shown in Land Use, which is usually the case. If the country was mostly desert and the farmers used irrigation (eg Egypt) then FARMLAND would be high.
VILGAP sets the distance between farming communities around the city. The closer villages are, the smaller they will be. Set it very low (0.2?) and you will see the villages vanish to be replaced by farmsteads.
A statistic to watch is RURAL_EDGE, which indicates how far the furthest away farmer has to travel to sell his food in the city market. Obviously if he has a horse and cart on a dirt track rather than a refrigerated truck on a freeway his travel distance is more limited. Try giving a TL3 city a million inhabitants and you'll see the problem. CCOUNT can help here by breaking the big city up into several smaller ones, and COASTAL by adding a fish market.
So how did ancient cities get round this problem? Grain ships, in the case of classical Athens and Rome. IMPORT% simulates this. A negative IMPORT% represents food exporting.

After playing around with city populations for a while, at MAXCITY below type the population of the largest city you want in your country.
Below will magically appear the reccomended number of cities. BIGCIT are cities of about the size you put in. Obviously you should have at least 1.0 of them! SMALLCIT cities are around one tenth the size and TOWNS one hundredth the size, but you can stick two or three together to make intermediate sizes.
Off to the right is a table for setting AR for the various city sizes. At later TLs AR is likely to be higher for big cities than small towns.
The way city size was related to 'reality' is on the right under Calibration: York is a medieval city I happen to be familiar with. Change the data and watch the effects.
Population Densities: scattered around the spreadsheet are RURDENSITY, FARMDENS, WILDENS, MDENS and 'City Density'. FARMDENS, unlike the others, is a theoretical figure.
Finally top right is the Tech Table, which enables different historical periods to be simulated. For example you will see that Nomads don't have a standing army or cities. This table is not totally calibrated - TL3 seems right economically for England in 1340. The rightmost column is for experimenting. Have fun!

'City' Notes

Units: if you prefer to work in kilometres, ri or whatever then feel free, just remember to be consistent. Besides the obvious (HEX, LAND, COAST, VILGAP and the city calibration area) you will also have to adjust POPCONST. There are no 'hidden' unit dependent constants.
Ed Stephan's original formulae appear at B14 and F41. His thesis is that doubling area doesn't double population for both countries and cities in realworld situations.

A Spreadsheet scenario - London and England 1340

HEX      25     LAND       100   COAST        10     POPCONT  25   CLIM  1
YIELD     1     EXTRA        0   URBAN         0.2   TL        3
ARABLE   40     PASTURE     30   WOODLAND     10
COASTAL   1     POP     50,000   CCOUNT        2     AR        7
FARMLAND  1.4   VILGAP       1   MAXCITY  50,000

Results:

Population 5.4 million. Food prices 102%
London Rural Edge 24 miles. Other cities: Bristol 17,000, Norwich and York 8,000.

England's population has been steadily growing over the past three centuries. Now just as it reaches maximum the climate changes for the worse as unseasonal torrential rain causes crop failures, sheep and cattle murrains. Farmers respond by ploughing up pastureland, slaughtering livestock but this can only last a few seasons before the marginal soil becomes exhausted, particularly with less manure for fertiliser, and crop yields start to fall again. Malnourished and dispirited, the people easily succomb to the Black Death as it sweeps across the country in 1349. Within 18 months 40% are dead. It will take two hundred years for the European economy to recover.
Let's try this out. There are already two Warnings lit up, they relate to food prices and shortage of land but are not serious - yet. Change CLIM to 0.9. On come more warnings! Rural Overpopulation will cause peasants to drift to the cities, a trend seen in many 20th Century Third World countries. So increase Urban to 0.3. See - warnings went out.
Now plough up some pastureland: ARABLE 45, PASTURE 25. That improved things a bit, keep going until Rural Shortages end.
CLIM to 0.8. You might by this time be considering importing food. Try IMPORT%=20. It seems to make things worse! The imported food only reaches the urban population and you have just deprived a lot of farmers of their customers, so Rural Overpopulation results.
Plough up more pasture until the FOOD SHORTAGE is resolved. In a few years comes the consequence: YIELD down to 0.9. This is the beginning of a downward spiral.
After trying and failing to resolve this one, let the Black Death strike: EXTRA to -40%. The refugees can return to the countryside. You still have food problems due to soil exhaustion, so return Land Use to the original settings. Eventually the CLIMate will improve, but EXTRA will not for a century or more as fresh outbreaks of plague prevent population growth.

London's 'subcity' is Westminster, site of the king's palace and seperated from the City of London by open fields that were not finally built over until the mid-17th century. Statisticians naturally count the two as one in medieval times.

TLs 0 and 1. With no cities the spreadsheet has to modify itself: MDENS loses it's meaning. FARMLAND should be set to =1 otherwise it will distort other results. You will find Nomads need a lot of Pasture to survive, and EXTRA will have to come down.

The spreadsheet does not check it's results everywhere, so look over the whole sheet for anomalies. One that puzzled me was when WILDDENS went negative. It turned out that URBAN was too high - all the farmers were feeding the cities and there was still a food shortage. Push things further and the empty wilderness will vanish under housing tracts and wheat fields, whereupon WILDDENS confusingly goes positive again... The 'Warnings' catch some of the obvious problems.