"In Book IV of the 1680 compilation of The Laws of the Indies, plans were set forth for settlers in high detail on every facet of creating a community, including town planning. Examples of the diverse range of rules include:
- Those colonists who should want to make a commitment to building a new settlement in the form and manner already prescribed, be it of more or less than 30 vecinos (freemen), (know that) it should be of no less than twelve persons and be awarded the authorization and territory in accordance with the prescribed conditions.
- Having made the selection of the site where the town is to be built, it must, as already stated, be in an elevated and healthy location; [be] with means of fortification; [have] fertile soil and with plenty of land for farming and pasturage; have fuel, timber, and resources; [have] fresh water, a native population, ease of transport, access and exit; [and be] open to the north wind; and, if on the coast, due consideration should be paid to the quality of the harbor and that the sea does not lie to the south or west; and if possible not near lagoons or marshes in which poisonous animals and polluted air and water breed.
- The colonists shall try as far as possible to have the buildings all of one type for the sake of the beauty of the town.
- Within the town, a commons shall be delimited, large enough that although the population may experience a rapid expansion, there will always be sufficient space where the people may go to for recreation and take their cattle to pasture without them making any damage.
- The site and building lots for slaughter houses, fisheries, tanneries, and other business which produce filth shall be so placed that the filth can easily be disposed of.
These rules are part of a body of 148 regulations configuring any settlement according to the rule of Spain and its colonies. This continued as a precedent in all towns under Spanish control until the relinquishing of the land to others, as in the case of the American colonies and their growth; however, the Laws of the Indies still serve as an example to design guidelines for communities today.
The Laws specify many details of towns. A plan is made centered on a Plaza Mayor (main square) of size within specified limits, from which twelve straight streets are built in a rectilinear grid. The directions of the streets are chosen according to the prevailing winds, to protect the Plaza Mayor. There is great detail, down to a hospital for non-contagious cases near the church, and one for contagious diseases further away.
Most townships founded in any part of the Spanish Empire in America before the various parts became independent countries would have been planned according to the Laws, including many townships with Spanish names in what is now the United States. The rectilinear grid of streets is very different from the haphazard layout of the many old townships in Europe which just grew.”
Jasper Johns, Gray Numbers, 1958