## 1 Introduction
Remote sensing is increasingly leveraged to identify attributes such as the construction age, the roof materials through both manual classification and multi/hyperspectral image analysis [11; 13; 14], and urban compactness [15]. While most existing exposure studies focus on urban areas in high-income countries like those in Western Europe [16; 17], the United States [18; 19], Japan [20], and China [10; 21; 22], there is a growing need for similar assessments in data-scarce but seismically active regions such as Central America [23; 24], the Caribbean [11], Pacific South America [25; 26], and the Pacific Ring of Fire [8; 9]. In such contexts, the availability and strategic use of open-access geospatial data become particularly critical for improving seismic risk mitigation efforts. Costa Rica, located within the seismically active zone, exemplifies the need for robust seismic exposure assessments. The Gran Area Metropolitan (GAM), which includes the capital city San Jose and constitutes the most densely populated region of the country, has approximately 0% of the country's population. Historically, the GAM has experienced numerous destructive earthquakes due to its location within the tectonically active Central Valley, which is intersected by a complex system of active faults. In particular, several active fault systems are located in close proximity to the Central Canton of San Jose, which could generate critical hazard scenarios [27]. Since the publication of its first seismic code in 1974 [28] by the CFIA (Colegio Federado de Ingenieros y Arquitectos de Costa Rica), Costa Rica has progressively incorporated advanced seismic design principles into its building regulations. The 1986 code [29] introduced seismic risk studies and standards for prefabricated systems, while the 2002 code [30] expanded structural classifications and adopted nonlinear analysis methods. The most recent code in 2010 [31] further updated design requirements, particularly for timber and steel constructions. These evolving regulations offer a robust framework for distinguishing between pre- and post-code structures based on their Lateral load-resisting system. Several exposure studies have been conducted in Costa Rica, predominantly focusing on the capital city. These studies have employed diverse methodologies, ranging from basic census-based estimates to the use of tools such as Hazus [32] and GEM [33]. A detailed summary of these efforts, including their spatial scales, data sources, and attributes assessed, is provided in Table 1. Recent projects have increasingly adopted geometric technologies to enhance the accuracy, efficiency, and granularity of exposure datasets, positioning Costa Rica as a relevant case study in the broader context of seismic risk assessment in data-limited settings. Recent technological advancements have improved the precision and depth of building characterization for seismic assessment. In Costa Rica, there has been a growing adoption of the Global Earthquake Model (GEM) methodology, representing a milestone toward the use of standardized, internationally recognized frameworks for evaluating seismic exposure in a region historically limited by data constraints. The objective of this research is to improve the technical and economic efficiency of seismic exposure studies in areas with high risk and data scarcity by reducing time and costs. To this end, a methodology for the obtention of GEDs and the classification of buildings is developed, ensuring the achievement of building-scale results and the optimum transfer of knowledge to competent institutions. The main contribution of this methodology is the efficient characterization of all buildings in a city with relevant exposure attributes obtained from open geospatial sources. The use of geomatic techniques to determine building attributes at the individual scale marks a new milestone in seismic exposure studies in Costa Rica in comparison to previous studies (Table 1).