Information about forest structures is becoming crucial to Earth's global carbon cycle, forest habitats and biodiversity. The Global Ecosystem Dynamics Investigation (GEDI) provides 25-m diameter footprints of the surface for 3D structure measurements. The main goal of this study is to compare 12 031 footprints of GEDI data with other airborne and spaceborne Digital Elevation Models (DEMs) for Southwest Spain. Ground elevation differences (ELM) are analyzed by comparing GEDI measurements with ALS LiDAR-and TanDEM-X-derived DEMs. The vertical structure (RH100) is compared to the ALS LiDAR measurement. Ten zones are analyzed, considering different degrees of coverage and slopes. We achieved an RMSE of 6.13 m for the ELM when comparing GEDI and LiDAR data and an RMSE of 7.14 m when comparing GEDI and TanDEM-X data. For some of the studied areas, these values were considerably smaller, with RMSE values even lower than 1 m. For the RH100 metric, an RMSE of 3.56 m was achieved when comparing GEDI and LiDAR data, but again with a minimum value of 2.09 m for one zone. The results show a clear relation to coverage and slope, especially for the latter. This work also evaluates the positional uncertainty of GEDI footprints, shifting them ±10 and ±5 m along and across the track of the satellite orbit and their intermediate angular positions. The outcomes reveal a strong tendency to obtain better results in the ELM when setting the footprint to 270° and displacing it within 10 m of its positional uncertainty in comparison with the LiDAR and TanDEM-X data.

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Improving the supply and accessibility of public services and facilities in order to satisfy the basic daily needs of the population is one of the premises to be taken into account in the spatial planning of a city. These aspects directly affect the decision-making process in terms of governance and management at the municipal level. In this sense, this research aims to quantify the degree of territorial accessibility available to residents of the city of Cáceres to basic health facilities using public transport, focusing on the recent opening of the new University Hospital on the outskirts of the city and the consequent creation of specific bus lines that provide the transfer service.For the development of this work, the following elements have been analysed: a) the different routes available by public transport, b) the set of bus stops present in the city and their distribution within the urban area, c) the characteristics of the potential users of the hospital by establishing age groups and d) the relationship between its initial location (the doorways of the different homes) and the point of access to the public transport service. From the methodological point of view, geographic information systems have been selected as a computer tool for the development of the scientific process (due to their analytical potential), given that they allow the measurement of geographic accessibility by means of applications based on network analysis. The visualization of the information on the accessibility results obtained is carried out by means of raster cartographic representation. Considering the minimum access time to the hospital as a factor of analysis, there are notable differences between different neighborhoods in the city. However, when subdivided into time slots, no substantial differences can be observed. On the other hand, a higher population density is clearly observed in the inner-city districts.