Spatial Data
Spatial data files and information about the applications of GIS research within the SALURBAL project.
Geographic Units
The SALURBAL team has developed a rigorous protocol for defining cities, sub-cities, and neighborhoods. This process allows us to study and compare urban environments and their health impacts across cities in 11 countries in Latin America: Argentina, Brazil, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Mexico, Nicaragua, Panama, and Peru.
We undertook a systematic approach to identify and define SALURBAL cities. The approach has guided the definition of geographic areas to which all SALURBAL data is linked. You can read more about this process in “Building a Data Platform for Cross-Country Urban Health Studies” or scroll through a summary of this process in our interactive “What is a SALURBAL city”.
| Country | City | Sub-city | Neighborhood |
|---|---|---|---|
| AR | 33 | 110 | 2409 |
| BR | 152 | 422 | 4023 |
| CL | 21 | 81 | 3913 |
| CO | 35 | 84 | 3781 |
| CR | 1 | 29 | 173 |
| GT | 3 | 20 | 4024 |
| MX | 92 | 406 | 32927 |
| NI | 5 | 11 | — |
| PA | 3 | 82 | 1791 |
| PE | 23 | 169 | 3775 |
| SV | 3 | 22 | — |
Spatial Boundaries
To facilitate some types of mapping and analysis, versions available above include or exclude small islands that are part of our definition of the city.
SALURBAL Spatial Data
In order to study urban environments and their health impacts it is necessary to identify the locations where exposures and outcomes occur, which requires spatial data. The use of a Geographic Information Systems (GIS) is an integral part of SALURBAL's approach to spatial data management. GIS is a framework for gathering, managing and analyzing spatial data. The spatial datasets that can be analyzed with GIS software include information about the locations and shapes of geographic features and the relationships between them, usually stored as coordinates and topology, as well as related attribute data organized for efficient storage and retrieval. Public health researchers often use the term “variables” to describe the columns in a data table that in GIS are called “Attributes” (See ESRI's GIS Dictionary for additional information about GIS terminology).
The SALURBAL Data and Methods Core (DMC) has focused on compiling spatial datasets representing administrative boundaries for different geographic levels and different time periods. The DMC has worked on linking health outcomes to these boundaries. Other members of the SALURBAL team use spatial data to develop measures that can be used for public health research. In particular, the Climate and Environment Core (CEC) has worked extensively with many spatial sets to derive measures of climate variables, and the built and natural environment for the different geographic levels used for SALURBAL.
The spatial datasets compiled by the DMC can be used for many different purposes including:
- Delineating the spatial extent of study areas (cities, L1AD) and sub areas (L2, L3)
- Documenting changes in spatial boundaries over time
- Organizing and managing place based data
- Linking together multiple place based datasets from multiple sources (e.g. census data with measures derived from satellite imagery)
- Spatial analyses: calculating distances, spatial overlaps, identifying contiguous areas, etc.
- Exploring spatial relationships and patterns
- Mapping demographics, exposures, outcomes, results, etc. in online interactive maps, static maps for presentations or publications
- Providing context to discussions of results
Spatial datasets at the DMC include data obtained from authoritative sources, data extracted for SALURBAL cities, and data modified or created by SALURBAL, as well as contextual data useful for preparing maps. A subset of these datasets are available through the SALURBAL Portal.
Software
DMC members affiliated with Drexel University have access to ESRI software through an Educational Site License and use ArcGISPro 3.1.2 to process spatial data. ESRI is the global market leader in GIS software and is a member of the Open Geospatial Consortium. Spatial data formats (including file geodatabases currently in use, and shapefiles from the 1990s) developed by ESRI are used widely and are accessible with non-ESRI software.