Typically, removal of the existing settlement is the first idea considered when planning improvements for squatter developments. In practice, however, available funds will probably not be sufficient to implement major changes. With those restrictions in mind, the questions then become: Which areas to improve, and to what extent? Which changes are feasible, and which are impossible?

The answers to these questions were obtained as a result of projects developed for the barrio of Petare, where the use of GIS tools was key for supporting sustainable answers. Our case study was part of a five-year World Bank program for upgrading squatter developments in Caracas. The plan covered different scales, from the whole urban design unit to the small neighborhoods (or condominiums, as residents call them). In Petare, a combined evaluation of the site's environment, urban built conditions, and social networks provided the framework for spatial change that guided the improvement plans.

Understanding complex, high-density squatter developments can be a difficult task. Social values hidden behind complex built environments can easily be neglected in a traditional site analysis. In poor areas, where social ties support daily survival, the urban built environment should be evaluated as a container of social values. A sustainable scenario for development must fit buildings and social needs within the conditions dictated by the geography of the site; therefore, we also need a full understanding of the site's environmental conditions.

Environmental Limitations

Site analysis is usually the first step when developing plans for improvement, and planning for squatter developments is no different. We need a full understanding of the site's environmental conditions to establish occupation rules and to determine whether or not the built environment is adapted to these conditions.

Environmental limitations are the main constraint for urban development, yet we don't manage these constraints in squatter developments as we do in the formal areas of the city. In formal areas, established development rules guide occupation. In squatter developments, the inhabitants' imperative need for land guides occupation, regardless of environmental restrictions.

Typical squatter development, demonstrating high population density and use of all available space.

Urban planning agencies do not usually have alternative policies for squatter developments, other than declaring the areas unsuitable for urban development. Establishing general development guidelines can help us improve living conditions whenever relocation is not a policy.

Analyzing the Site

In squatter developments, GIS can help overcome the absence of the basic terrain data that's usually available in developed countries. Using simple overlays and relationships between different themes, GIS helps to locate and describe the behavior of the site. Usually, basic maps in developing countries come from multiple sources and have diverse scales, resolutions, and precisions. Layering them requires that these maps first be standardized, rescaled, and adjusted to fit and recognize common borders and limits.

Environmental Evaluation. In squatter developments, environmental analysis must identify relevant issues that affect community health, terrain stability, flooding risks, and other subjects. The lack of open space, excessive population density, a high criminal index, and other social and environmental limitations require a special review. A combined evaluation of all issues is easier if the proper data is correlated through GIS.

Physical and Social Components. To identify the internal physical and social networks contained within the built environment, site analysis must emphasize studies of urban form. We need to establish the capacity of the urban form to support changes without affecting the social network and the inhabitants' systems of orientation. The basic information needed to establish these limits include spatial (physical) and non-spatial (social) variables.

Patterns of connection between individual buildings are usually analyzed through typological studies. In massive built forms, where buildings are difficult to individualize, studies should focus on group typologies.

Ties between groups constitute the social network, highly appreciated by barrio residents. In complex squatter developments, the only way to define community boundaries is through residents' participation. Because boundaries are the main social constraints for change, improvement plans must identify and reinforce community boundaries.

Physical elements that perform a social role, such as pedestrian intersections where groups interact or signs that identify places linked to community history, can be difficult to perceive. Identifying these elements is basic to understanding the relationships of social groups to the built environment.