Detecting Urban Change with Open-Source GIS programs: A Case Study in Guayaquil

Abstract. Urban sprawl constitutes a significant challenge to sustainable development, particularly in rapidly expanding urban environments. In the case of Guayaquil, in Ecuador, the construction of Perimetral Avenue in 1987 facilitated uncontrolled urban transformation. The absence of effective planning and oversight has led to the conversion of mangrove ecosystems into urban areas in specific sectors, with Isla Trinitaria notably experiencing the most substantial transformation, without yet having a clear strategy or methodology for responding to the problem. Within this framework, the objective of the study is to propose a methodology utilizing free software for optimizing resources in territorial planning. This investigation employed data from MapBiomas and the municipal urban cadastre; spatial information was integrated through free software platforms such as QGIS and PostgreSQL/PostGIS. One of the stages of the methodology included the vectorization of raster images, conducting spatial intersections with the cadastral data, and establishing a geographic database to enable SQL queries. The results indicated urban expansion from 2.1% in 1985 to full occupation in 2010, with a peak in construction activity in 1997. Furthermore, limitations such as low image resolution and data absence due to cloud cover were identified. This proposal aims to enhance sustainable urban planning by leveraging accessible tools, thereby contributing to effective territorial planning and informed decision-making in urban contexts.