7.3 Suitability Analysis Because most red fields were capable for several green field types, suitability mapping was conducted to refine the previous analysis. Suitability mapping built upon capability mapping by using the results of capability mapping as a base and adding additional criteria. It also offered a more detailed picture of the suitability of red field sites by using an additive process that revealed different levels of suitability. The results of this are suitability maps that are more selective than those that were obtained with capability mapping alone.
Criteria Additional red field characteristics were identified to serve as suitability criteria for each green field type (Table 7–2). The red field characteristics included in the list of criteria are size, vacancy, proximity to bike lanes, and proximity to nodes. While the set of criteria differed depending upon the type of green field solution, one criterion that was common to all green field types was proximity to bike lanes. Red fields close to bike lanes were considered to be well connected, more visible, and easier to access, which would allow more people to be served by green fields located there. Community green fields are meant to create and enhance social infrastructure. Because their functionality hinges on social systems, location and social relevance are highly important. Being located on a commercial corridor was a criterion for community green fields during capability mapping, because it is an indicator of location for social function. In addition, proximity to nodes and proximity to bike lanes are both measures of location. More specifically, they indicate locations that are likely to benefit from high volumes of people. Therefore, red fields that were close to bike lanes and nodes were determined to be more suitable for community green fields. For the other green field types — ecology, urban agriculture, and recreation — suitability depended on size, vacancy and proximity to bike lanes. Bike lanes are also significant for these green field types because all green field types would benefit from increased accessibility and
98
Red Fields to Green Fields Los Angeles
Size
Vacancy
Bike Lanes
Nodes
Recreation
1
1
1
0
Urban Agriculture
1
1
1
0
Ecology
1
1
1
0
Community
0
0
1
1
Table 7–2. Additive criteria for suitability
they contribute to the creation of a green network that would connect neighborhoods throughout Los Angeles with green infrastructure and alternative transportation. Vacancy is an important criterion for suitability because building demolition has associated costs, and most green field types do not require a building. There are two reasons why size is also an important criterion for suitability. One is that larger green fields can have a greater positive impact and serve more people than small green fields. The other is that size may limit the programming that is possible on a site, especially for certain green field types such as engineered wetlands, urban agriculture, and active recreation.
Mapping Following the identification of suitability criteria, a GIS model was developed to map suitability. In this model, only sites that were previously found to be capable were included in suitability mapping. Furthermore, suitability criteria were determined to be cumulative, so that sites that met multiple criteria would have a higher level of suitability than sites that only met one criterion. This was accomplished by assigning red field sites binary values for each suitability criterion. Sites that met a given criterion would be assigned a value of “1” for that criterion, while sites that did not would be assigned a value of “0.” The level of suitability of a red field for a