THE GRID PLANS

The geometry is present in the cities, and more concretely in the expansion projects of the big cities. The growth of the population was demanding the construction of new places, new neighborhoods in order that the people could have somewhere to live.

Many cities followed a grid plan. A grid plan is a type of urban development planning that organizes a city by means of the design of its streets in right angles, creating rectangular blocks. The appellative "grid" ("hipodámico" in Spanish) comes from the Greek architect Hippodamus of Miletus, considered one of the parents of the urbanism, whose organizations plans were characterized by a design of rectilinear streets that were crossing in right angle. An urban plane called orthogonal plane is used. The cities that present this type of urban planning have a perfectly distinguishable urban morphology in its tracing, as we can see in the image (tracing of Barcelona).

This type of planning has an advantage: its parceling is easier due to the regularity of the form of its blocks. In spite of this apparent simplicity, this type of plan presents some disadvantages, since it extends the length of the distances. To avoid it, diagonal streets are built. In order to increase the visibility in the crossings of the streets, bevels can be designed, which are an urban resource that consists in removing the corners of a building to have a better observation and to extend the crossings.

One of the cities in which it is possible to observe this planning is Barcelona, created by the engineer Ildefonso Cerdá. The "ensanche" extends along a big surface, with long streets and avenues, diagonals (one of them, the known one "Diagonal de Barcelona"), and 45º  bevels for a better visibility. 

To sum up, the city of Barcelona is a great example of how the geometry is a participant in the organization and distribution of the neighborhoods and places of a city.