Urban Morphology: Structure, Growth and Transformation of Cities

Urban Morphology

Urban morphology is the study of the external physical form of a city. It is influenced by the site, that is, the concrete space on which the city is located, and by its situation, meaning the relative position of the city with respect to the wider geographical environment.

The plan of a city is the set of built surfaces that form it. An irregular street layout, with streets that are not defined by straight lines, is common. The type of construction includes the arrangement of buildings, which can be compact, closed or open. Buildings may be collective or individual, with varying heights and floor counts, and their diverse uses shape urban space.

The Urban Structure

The Old Town

The old town is the part of the city that has been urbanized since its origin, often before the Industrial Revolution of the 19th century. Its heritage is linked to the Roman, Medieval and Renaissance periods. Old towns were often surrounded by walls with a defensive purpose.

• Irregular plan, with plots enclosed by buildings.
• Mostly single-family houses of one to three storeys.
• Diverse land uses, including housing, workshops, shops and warehouses.

The Plan of Roman Cities

Roman cities typically presented a regular layout, as seen in examples such as Zaragoza, León, Mérida and Tarragona.

The Medieval Period and Its Two Cultures

The medieval period in the Iberian Peninsula was shaped by two cultures: Christian and Muslim.

• Muslim city: The medina, with irregular streets and detached buildings. Examples include Córdoba, Seville and Toledo.
• Christian city: Surrounded by walls, with varied plans and detached buildings such as churches.

The Renaissance and the Baroque

• Renaissance: New, regular neighbourhoods were created alongside the old irregular streets and gates.
• Baroque: The creation of cities with broad avenues and straight lines symbolized power and order.

Transformations in the Industrial Era

In the 19th century, reforms in the 20th century affected the value of the historic centre. Many streets and squares were altered. In the second half of the 20th century, these areas were appreciated and their historic fabric was restored.

• The dense plot structure was used to make the most of land and buildings.
• The ground-floor uses of the old centre experienced change.

The Industrial City and the Ensanche

Modern industry attracted rural population to cities. Cities began to outgrow their historic walls, and new bourgeois areas and industrial zones were created.

In Burgos, the walls were demolished in order to build new boulevards. The Ensanche became a new expression of bourgeois ideas, with a regular plan and focus on hygiene.

• Regular plan: Straight streets intersecting at right angles, with low-density plots and spacious green areas, typically gardens. Residential use was predominant.
• Dense plots: Blocks were built on all four sides, with parks included in their design.
• Verticalization: Buildings became taller, replacing bourgeois villas and houses with multi-storey blocks of flats.

The Ensanche extended beyond the historic centre, which kept its original character.

Current Transformations in the Periphery

From the 1960s onward, the main Spanish cities experienced enormous growth due to demographic increase, industrial development and the expansion of services. Extensive peripheries were created, with residential neighbourhoods that presented social heterogeneity, largely derived from land prices that decreased with distance from the centre.

• Marginal neighbourhoods: Illegal land occupation led to unorganized urbanism.
• Official housing promotion: Neighbourhoods built through official promotion had further development between 1940 and 1960.
• Polygons: Large housing estates appeared on the periphery.
• Single-family dwellings became rare on the periphery from the 1980s onward.

Urban Agglomerations

Some cities grew and joined other cores, connecting populations. A metropolitan area is a large urban extension around an important city, which includes municipalities with significant economic and social relations.

Other Types of Agglomeration

• Conurbation: A continuous urban area formed when two or more cities grow in parallel and join together, such as Málaga and Marbella.
• Urban region: A discontinuous urban area that integrates dispersed cities.
• Megalopolis: Arises when urbanization reaches a supra-regional scale.