In Caracas, Venezuela, GIS Guides Assistance for Underdeveloped Urban Areas
By Rosario Giusti de Pèrez, AT Systems, Maracaibo, Venezuela
Concern for improving the urban slum neighborhoods in the cities of Venezuela has led the National Housing Council (CONAVI) and the Foundation for Community Development (FUNDACOMUN) to design a national improvement urban policy for these marginal neighborhoods. Some of the urban design policy issues concern Petare, a marginal area within the capital city of Caracas, and include reinforcement of the formal and social organizational patterns within the urban area and conservation of the built environment. If necessary, construction within the built environment will be restricted so it will not substantially modify the environmental aspects that are enjoyed by the urban dwellers.
In general, the urban design proposals were designed to pursue balancing the quality of life with maintaining important character aspects of the surrounding neighborhood environment. Thus, the integration of neighborhood and city is supported by preserving the existing relationships between spatial and social systems. This kind of urban intervention promotes social and physical cohesion within the community. Building spatial information for identifying and analyzing these relationships was one of the main tasks resolved with GIS technology.
Existing Settlement Conditions
The informal occupation of the urban periphery in cities in Venezuela generates different physical and spatial situations that respond to the characteristics of the city where development is proposed. Differences in urban scenes, density, and availability of land for urban development are key aspects when creating urban redesign proposals.
All informal urban periphery settlements in Venezuela tend to possess similar characteristics. These characteristics include the absence of a defined urban structure or identity, discontinuous internal urban patterns unrelated to the surrounding formal development, and a deficit of public services and infrastructure (mainly sewers and drainage).
Petare is a highly populated neighborhood with an area of approximately 87 hectares in the capital city. It is characterized by an extensive and homogeneous residential fabric and lacks available low-cost urban land. It is located on a hillside with irregular topography and steep slopes, sometimes equaling a 40 percent grade, and consists of a discontinuous street pattern. There are, however, some official public services within the residential fabric.
Site Analysis as a Basis for Identifying Sustainability
One of the goals in determining the sustainability of the community was to identify community subdivisions unrelated to physical conditions. Identifying building typologies in highly concentrated developments, such as Petare, with very steep slopes and residential densities between 500 and 800 inhabitants per hectare did not allow for the classical definition of residential typologies, so the analysis focused on using aggregation typologies.
Types were identified as individual units or groups of units. The groups were classified and assigned a typology according to the form in which the units aggregated. The typologies were broken down further by creating various maps and feature classes that identified more specific categories. One category, referred to as hard and soft areas, was created from different combinations of house and block types. Hard refers to areas that are difficult to change because they are strongly built and interwoven, conforming to well-defined blocks of building units and functioning as groups. Soft areas are not well structured, lack a block definition, and allow changes that provide urban order and social cohesion.
A synthesis map that displayed the feasibility for urban intervention was developed to trace access roads. Grades of feasibility for urban intervention were established using the 10 combinations of hard and soft areas and grouping them to obtain four grades of feasibility: soft and accessible, soft and inaccessible, hard and accessible, and hard and inaccessible.
Meetings held with community leaders and community groups revealed problems as well as the potential for development of the neighborhood. These results were mapped and characterized as either restrictions or opportunities for physical and spatial development. This map, complemented by a list of problems and aspirations of the community, was the basis for developing the urban design proposal. In Petare, this map was created by overlaying the layers of hard and soft areas plus using accessibility and proximity maps developed with ArcView Spatial Analyst.
The search for solutions to infrastructural problems was a priority for the communities, since they felt these solutions would improve the quality of their public spaces. They considered this more important than demanding improvements to their homes, which they felt they could deal with in the near future. The search for open space was directed toward the recovery of vacant or abandoned land in dispersed settlements or land that was left out as the result of interventions made to improve the street system.
The proposal created from the analyzed data proved that the communities could look at developing these urban areas while respecting the neighborhood's characteristics by not modifying the "spirit of the neighborhood" or "social relationships." These urban aspects were approached by creating the Implementation Model and Building Guidelines. This was based on the restrictions and opportunities for development, as identified by the communities and their technicians and approved by the communities in an open assembly. The social aspects of the model were supported in an urban proposal, which reaffirmed the community system of relationships and the social cohesion of the different neighborhood groups.
The collective identity was built using an urban design project that articulated the urban requirements and community activities. This project generated a future urban scene that integrated new elements and collective memories of the neighborhood residents. These urban interventions pursue a better quality of life for the neighborhood dwellers, based on a sustainable urban approach that incorporates the physical, social, and economic opportunities of the site.
In Petare the lack of urban land for locating new facilities was overcome by proposing horizontal extensions of very small dimensions and vertical growth of existing educational and health facilities. Open space for public use was a product of interventions related to urban improvements. When this recovered space (from interventions) had suitable dimensions (more than approximately 50 square meters), housing or community facilities were proposed. The pedestrian system of stairs and sidewalks was improved and extended including new elevated sidewalks that allow pedestrians to move along next to the adjacent highwaya main access to the neighborhood.
This analysis required acquiring a lot of data about the dwellings; the people, their needs and capabilities, and their built environment; and the area's physical conditions and residents' behavior. Using GIS was the best way to work with this geospatial data. ArcView Spatial Analyst was used throughout the entire urban analysis and design process.
For more information, contact Ramon A. Perez, president, Grupo Esri de Venezuela, C.A. (tel.: 58-261-793-2312, e-mail: email@example.com).