Corner regards the agency of mapping as speculation, critique and invention. By introducing terms and techniques about his understanding of maps, Corner develops the idea that formal expression does not evolve quick enough to be relevant as long as the informal settlement starts getting more demand and rights.

Conventionally, neutrality is one of the conventional characteristics of “mapping”. However, the position, orientation, and differences of focus in maps all indicate certain socio-political statement. In Corner’s opinion, the abstractness of the map already brings in a subjective position of the mapmaker. “The application of judgment, subjectively constituted, is precisely what makes a map more a project than a ‘mere’ empirical description.”(Corner, 223)

The subjectivity of mapping leads to the re-thinking of the perspective in mapping. Banham, mentioned by Corner, suggests more attention on the problem that some mappings “adopt a somewhat naïve and insular, even elitist, position.”(Corner, 226)
“ The implications of a world derived more from cultural invention than from a pre-formed ‘nature’ have barely begun to be explored.” (Corner, 223) The mapping for the Watery Void project discovers the potential and pushes the design into a level with reconciled metropolitan and local scale. (Franco, 85)

As Corner mentions in the essay, he discusses “mapping as an active agent of cultural intervention.” Mapping is more like a creative activity that is not only a simple mirror of the existing reality, but also the design process for disclosing new reality. Comparing to “tracing”, mapping is a process of discovering and adding new elements in design.

Another comparison of concepts in Corner’s article is “mapping” and “planning”. He uses Harvey’s idea of “utopia of form” vs. “utopia of process” explaining the difference between “mapping” and “planning”. According to Corner’s description, mapping is definitely more useful and suitable for informal settlement, as mapping entails searching in the existing milieu instead of top-down imposed idealized formal project. Corner believes that various hidden forces underlie the workings of a place, which makes the reality more complex. Mapping of Sao Paulo’s infrastructure should not only be considered as a “technical and functional artifact”; but instead, the interrelationships and interactions between the rising middle class, the new demands coming together, as well as the interest of both central and peripheral residence cannot be ignored any more. One main concept of the Watery Void project is to use and serve for these interrelationships that form the complexity of mapping. Water, more than a nature resource in planning, becomes one main element bridging favelas with formal sector of the city.

James Corner: Agency of Mapping
Franco de Mello: Filling Voids