L'incendi de 1998 a la Catalunya Central. Anàlisi dels canvis en les cobertes del sòl (1956-2009) a diferents escales, d'incendi i de finca

L'objectiu d'aquest treball és fer una diagnosi de l'incendi ocorregut l'any 1998 a la Catalunya Central, a partir de l'anàlisi dels canvis en les cobertes del sòl a diferents escales i la seva relació amb els Grans Incendis Forestals (GIF). Metodològicament, l'estudi combina l'anàlisi quantitativa (cobertes del sòl) amb l'anàlisi qualitativa (entrevistes a dos propietaris de finques afectades). L'anàlisi dels canvis s'ha realitzat a escala d'incendi i de finca, en els períodes 1956-2009, 1956-1993 i 1993-2009. Els resultats a escala d'incendi mostren una tendència a la transició forestal en tot el període d'anàlisi. A escala de finca, s'observa una afectació de l'incendi diferent a les dues propietats, relacionada amb una diferent gestió dels usos del sòl, i es conclou que després del Gran Incendi Forestal apareix una diversitat de cobertes a la parcel·la més afectada que pot ser una oportunitat pel trencament de l'homogeneïtat forestal i per a repensar la seva gestió.The aim of this study is to diagnose the wildfire occurred in 1998 in Central Catalonia, based on the changes in land cover at different scales analysis and its relation to Great Forest Fires (GIF). Methodologically, the study combines quantitative analysis (land cover) with the analysis of qualitative (two interviews with affected landowners). The analysis of changes has been made at fire and property scales, in the periods 1956- 2009, 1956-1993 and 1993-2009. The results at the fire scale show a trend close to a forest transition throughout the period. At farm scale, there is a different involvement of the fire at two properties, associated to different land use management, concluding that after the Great Forest Fire in the properties that are more affected in which appear a diversity of covers that could offer an opportunity to break the forest homogeneity and rethink its management.El objetivo de este trabajo es hacer un diagnóstico del incendio ocurrido en 1998 en la Catalunya Central, a partir del análisis de los cambios en las cubiertas del suelo a diferentes escalas y su relación con los Grandes Incendios Forestales (GIF). Metodológicamente, el estudio combina el análisis de tipo cuantitativo (cubiertas del suelo) con el análisis de tipo cualitativo (entrevistas a dos propietarios de fincas afectadas). El análisis de los cambiosse ha realizado a escala de incendio y de finca, en los períodos 1956-2009, 1956-1993 y 1993-2009. Los resultados a escala de incendio muestran una tendencia a la transición forestal en todo el período de análisis. A escala de finca, se observa una afectación del incendio diferente a las dos propiedades, relacionada con una diferente gestión de los usos del suelo, concluyéndose que después del Gran Incendio Forestal aparece una diversidad de cubiertas en la parcela más afectada que puede ser una oportunidad para romper la homogeneidad forestal y repensar su gestión

An operational radiometric correction technique for shadow reduction in multispectral uav imagery

This study focuses on the recovery of information from shadowed pixels in RGB or multispectral imagery sensed from unmanned aerial vehicles (UAVs). The proposed technique is based on the concept that a property characterizing a given surface is its spectral reflectance, i.e., the ratio between the flux reflected by the surface and the radiant flux received by the surface, and this ratio is usually similar under direct-plus-diffuse irradiance and under diffuse irradiance when a Lambertian behavior can be assumed. Scene-dependent elements, such as trees, shrubs, man-made constructions, or terrain relief, can block part of the direct irradiance (usually sunbeams), in which part of the surface only receives diffuse irradiance. As a consequence, shadowed surfaces comprising pixels of the image created by the UAV remote sensor appear. Regardless of whether the imagery is analyzed by means of photointerpretation or digital classification methods, when the objective is to create land cover maps, it is hard to treat these areas in a coherent way in terms of the areas receiving direct and diffuse irradiance. The hypothesis of the present work is that the relationship between irradiance conditions in shadowed areas and non-shadowed areas can be determined by following classical empirical line techniques for fulfilling the objective of a coherent treatment in both kinds of areas. The novelty of the presented method relies on the simultaneous recovery of information in non-shadowed and shadowed areas by the in situ spectral reflectance measurements of characterized Lambertian targets followed by smoothing of the penumbra area. Once in the lab, firstly, we accurately detected the shadowed pixels by combining two well-known techniques for the detection of the shadowed areas: (1) using a physical approach based on the sun's position and the digital surface model of the area covered by the imagery; and (2) the image-based approach using the histogram properties of the intensity image. In this paper, we present the benefits of the combined usage of both techniques. Secondly, we applied a fit between non-shadowed and shadowed areas by using a twin set of spectrally characterized target sets. One set was placed under direct and diffuse irradiance (non-shadowed targets), whereas the second set (with the same spectral characteristics) was placed under diffuse irradiance (shadowed targets). Assuming that the reflectance of the homologous targets of each set was the same, we approximated the diffuse incoming irradiance through an empirical line correction. The model was applied to all detected shadowed areas in the whole scene. Finally, a smoothing filter was applied to the penumbra transitions. The presented empirical method allowed the operational and coherent recovery of information from shadowed areas, which is very common in high-resolution UAV imagery

Comparison of four UAV georeferencing methods for environmental monitoring purposes focusing on the combined use with airborne and satellite remote sensing platforms

Altres ajuts: C.P. is a recipient of a FI-DGR scholarship grant (2016B_00410). X.P. is a recipient of an ICREA Academia Excellence in Research Grant ().This work is aimed at the environmental remote sensing community that uses UAV optical frame imagery in combination with airborne and satellite data. Taking into account the economic costs involved and the time investment, we evaluated the fit-for-purpose accuracy of four positioning methods of UAV-acquired imagery: 1) direct georeferencing using the onboard raw GNSS (GNSSNAV) data, 2) direct georeferencing using Post-Processed Kinematic single-frequency carrier-phase without in situ ground support (PPK1), 3) direct georeferencing using Post-Processed Kinematic double-frequency carrier-phase GNSS data with in situ ground support (PPK2), and 4) indirect georeferencing using Ground Control Points (GCP). We tested a multispectral sensor and an RGB sensor, onboard multicopter platforms. Orthophotomosaics at <0.05 m spatial resolution were generated with photogrammetric software. The UAV image absolute accuracy was evaluated according to the ASPRS standards, wherein we used a set of GCPs as reference coordinates, which we surveyed with a differential GNSS static receiver. The raw onboard GNSSNAV solution yielded horizontal (radial) accuracies of RMSEr≤1.062 m and vertical accuracies of RMSEz≤4.209 m; PPK1 solution gave decimetric accuracies of RMSEr≤0.256 m and RMSEz≤0.238 m; PPK2 solution, gave centimetric accuracies of RMSEr≤0.036 m and RMSEz≤0.036 m. These results were further improved by using the GCP solution, which yielded accuracies of RMSEr≤0.023 m and RMSEz≤0.030 m. GNSSNAV solution is a fast and low-cost option that is useful for UAV imagery in combination with remote sensing products, such as Sentinel-2 satellite data. PPK1, which can register UAV imagery with remote sensing products up to 0.25 m pixel size, as WorldView-like satellite imagery, airborne lidar or orthoimagery, has a higher economic cost than the GNSSNAV solution. PPK2 is an acceptable option for registering remote sensing products of up to 0.05 m pixel size, as with other UAV images. Moreover, PPK2 can obtain accuracies that are approximate to the usual UAV pixel size (e.g. co-register in multitemporal studies), but it is more expensive than PPK1. Although indirect georeferencing can obtain the highest accuracy, it is nevertheless a time-consuming task, particularly if many GCPs have to be placed. The paper also provides the approximate cost of each solution

Monitoring opencast mine restorations using Unmanned Aerial System (UAS) imagery

Altres ajuts: Joan-Cristian Padró is a recipient of the FI-DGR scholarship grant (2016B_00410). Xavier Pons is a recipient of the ICREA Academia Excellence in Research Grant (2016-2020).Open-pit mine is still an unavoidable activity but can become unsustainable without the restoration of degraded sites. Monitoring the restoration after extractive activities is a legal requirement for mine companies and public administrations in many countries, involving financial provisions for environmental liabilities. The objective of this contribution is to present a rigorous, low-cost and easy-to-use application of Unmanned Aerial Systems (UAS) for supporting opencast mining and restoration monitoring, complementing the inspections with very high (<10 cm) spatial resolution multispectral imagery, and improving any restoration documentation with detailed land cover maps. The potential of UAS as a tool to control restoration works is presented in a calcareous quarry that has undergone different post-mining restoration actions in the last 20 years, representing 4 reclaimed stages. We used a small (<2 kg) drone equipped with a multispectral sensor, along with field spectroradiometer measurements that were used to radiometrically correct the UAS sensor data. Imagery was processed with photogrammetric and Remote Sensing and Geographical Information Systems software, resulting in spectral information, vegetation and soil indices, structural information and land cover maps. Spectral data and land cover classification, which were validated through ground-truth plots, aided in the detection and quantification of mine waste dumping, bare soil and other land cover extension. Moreover, plant formations and vegetation development were evaluated, allowing a quantitative, but at the same time visual and intuitive comparison with the surrounding reference systems. The protocol resulting from this research constitutes a pipeline solution intended for the implementation by public administrations and privates companies for precisely evaluating restoration dynamics in an expedient manner at a very affordable budget. Furthermore, the proposed solution prevents subjective interpretations by providing objective data, which integrate new technologies at the service of scientists, environmental managers and decision makers

StratoTrans : Unmanned Aerial System (UAS) 4G communication framework applied on the monitoring of road traffic and linear infrastructure

This study provides an operational solution to directly connect drones to internet by means of 4G telecommunications and exploit drone acquired data, including telemetry and imagery but focusing on video transmission. The novelty of this work is the application of 4G connection to link the drone directly to a data server where video (in this case to monitor road traffic) and imagery (in the case of linear infrastructures) are processed. However, this framework is appliable to any other monitoring purpose where the goal is to send real-time video or imagery to the headquarters where the drone data is processed, analyzed, and exploited. We describe a general framework and analyze some key points, such as the hardware to use, the data stream, and the network coverage, but also the complete resulting implementation of the applied unmanned aerial system (UAS) communication system through a Virtual Private Network (VPN) featuring a long-range telemetry high-capacity video link (up to 15 Mbps, 720 p video at 30 fps with 250 ms of latency). The application results in the real-time exploitation of the video, obtaining key information for traffic managers such as vehicle tracking, vehicle classification, speed estimation, and roundabout in-out matrices. The imagery downloads and storage is also performed thorough internet, although the Structure from Motion postprocessing is not real-time due to photogrammetric workflows. In conclusion, we describe a real-case application of drone connection to internet thorough 4G network, but it can be adapted to other applications. Although 5G will -in time- surpass 4G capacities, the described framework can enhance drone performance and facilitate paths for upgrading the connection of on-board devices to the 5G network

Drone-Based Identification of Erosive Processes in Open-Pit Mining Restored Areas

Altres ajuts: European Union LIFE20 PRE/IT/000007Unmanned Aerial Systems, or drones, are very helpful tools for managing open-pit mining operations and developing ecological restoration activities. This article presents a method for identifying water erosion processes in active quarries by means of drone imagery remote sensing, in the absence of pre-existing imagery or mapping for comparison. A Digital Elevation Model (DEM) with a spatial resolution (SR) >10 cm and an orthophoto with an SR >2.5 cm were generated from images captured with a drone and their subsequent photogrammetric processing. By using Geographical Information Systems tools to process the DEM, a detailed drainage network was obtained, the areas of detected water erosion were separated, and the watersheds in the gullies identified. Subsequently, an estimated DEM before the erosive processes was reconstructed by interpolating the gully ridges; this DEM serves as a reference for the relief before the erosion. To calculate the volume of eroded material, the DEM of Differences was calculated, which estimates the volume difference between the previously estimated DEM and the current DEM. Additionally, we calculated the material necessary for the geomorphological adaptation of the quarry and the slope map, which are two valuable factors closely related to the monitoring of erosive processes. The results obtained allowed us to identify the erosion factors quickly and accurately in this type of mining. In the case of water-filled quarries, it would be important to characterize the subsurface relief. Essentially, the presented method can be applied with affordable and non-invasive materials to create digital grid maps at 10 cm resolution, obtaining data ready for 3D metrics, being a very practical landscape modelling tool for characterizing the restoration evolution of open-pit mining spaces

Anàlisi dels canvis de les cobertes del sòl durant el període 1956-2009 en dues finques afectades per l'incendi de 1998 a la Catalunya Central

S'analitza la relació entre els incendis forestals i els canvis en les cobertes del sòl. En concret s'estudien els canvis que s'han donat entre el 1956 i el 2009 en dues finques afectades pel Gran Incendi Forestal (GIF) de la Catalunya Central l'any 1998, en les quals s'observa empíricament una diferent afectació del foc. Una de les finques s'ajusta a la Teoria de la Transició Forestal, mentre que l'altre finca ha mantingut la diversitat de tipologies de cobertes durant aquest temps. Utilitzant metodologia quantitativa (SIG) es comparen els Mapes de Cobertes del Sòl de Catalunya (MCSC) dels anys 1956, 1993 i 2009 tant de l'àrea afectada per l'incendi en el seu conjunt com de les dues finques en particular, amb la finalitat de descriure i quantificar els canvis en les cobertes del sòl. Utilitzant metodologia qualitativa, a partir d' entrevistes als propietaris de les finques, es busquen explicacions sobre com s'han gestionat les finques amb anterioritat a l'incendi i com s'estan gestionant un cop cremades. En conclusió, s'observa que després d'un GIF apareix una diversitat de cobertes semblant a la que hi havia abans de la Transició Forestal, una diversitat que si es manté pot ser una eina per reduir la intensitat d'incendis futurs en la mateix àrea.Se analiza la relación entre los incendios forestales y los cambios en las cubiertas del suelo. En concreto se estudian los cambios dados entre 1956 y 2009 en dos fincas afectadas por el Gran Incendio Forestal (GIF) de la Cataluña Central en el año 1998, en las cuales se observa empíricamente una diferente afectación del fuego. Una de las fincas se ajusta a la Teoría de la Transición Forestal, mientras que la otra finca ha mantenido la diversidad de tipologías de cubiertas durante este tiempo. Utilizando metodología cuantitativa (SIG) se comparan los Mapas de Cubiertas del Suelo de Cataluña (MCSC) de los años 1956, 1993 y 2009 tanto para la área del incendio en su conjunto como para las dos fincas en particular, con la finalidad de describir y cuantificar los cambios en las cubiertas del suelo. Utilizando metodología cualitativa, a partir de entrevistas a los propietarios de las fincas, se buscan explicaciones sobre la gestión de las fincas con anterioridad al incendio y sobre la gestión una vez quemadas. En conclusión, se observa que después de un GIF aparece una diversidad de cubiertas parecida a la que había antes de la Transición Forestal, una diversidad que si se mantiene puede ser una herramienta para reducir la intensidad de incendios futuros en la misma área.The relationship between forest fires and changes in land cover are analyzed. In particular given the changes between 1956 and 2009 on two properties affected by the Great Fire Forest (GFF) of Central Catalonia in 1998, in which a different fire affectation is empirically observed. One property is set to Forest Transition Theory, while the other property has maintained the diversity of cover distribution during this time. Using quantitative methodology (GIS ) and the Land Cover Map of Catalonia (LCMC) for the years 1956, 1993 and 2009 are compared for both the fire area as a whole and for the two properties in particular, in order to describe and quantify changes in land cover. Using qualitative methodology, based on interviews with landlords, are expected explanations on the management of the lands before the fire, and the management once burned. In conclusion, it appears that after a GIF covers distribution is quite similar to what it was before the Forest Transition, which if is maintained it may be a tool to reduce the intensity of future fires in the same are

UAS remote sensing products for supporting extraction management and restoration monitoring in open-pit mines

Accurate mapping of open-pit mine areas is a prerequisite for the efficient resource management of extractive companies, but also detailed mapping is a requirement for public administrations, especially regarding the monitoring of restored areas. In previous works, our team has contributed to a better knowledge of the use of Unmanned Aerial Systems (UAS) technologies for soil/vegetation restoration monitoring purposes, and in this work, we present a novel protocol to support combined interests of both private companies and governmental agencies. We introduce a case study in which we show the capability of multispectral sensors onboard of a low-weight multicopter to describe land cover typologies in restored areas (such as grass, scrubs, trees, topsoil and mine spoils) by applying remote sensing and GIS techniques. Moreover, we assess the capability of digital terrain models (Digital Elevation Model, Digital Surface Model, Digital Slope Model) derived from photogrammetric techniques, to provide useful and fast topographic information for the proper management of open-pit mine exploitation and restoration. By applying these techniques, we present a cost-effective workflow adequate to monitor land cover dynamics in restored areas, but also volumetric changes in stockpiles, waste dumps and extraction faces. This combined approach, supporting both environmental and industrial needs, aims to enhance the collaboration between sectors, establishing synergies, reducing costs by sharing knowledge, and adding transparency to their relation

Drone-Based Identification of Erosive Processes in Open-Pit Mining Restored Areas

Unmanned Aerial Systems, or drones, are very helpful tools for managing open-pit mining operations and developing ecological restoration activities. This article presents a method for identifying water erosion processes in active quarries by means of drone imagery remote sensing, in the absence of pre-existing imagery or mapping for comparison. A Digital Elevation Model (DEM) with a spatial resolution (SR) &gt;10 cm and an orthophoto with an SR &gt;2.5 cm were generated from images captured with a drone and their subsequent photogrammetric processing. By using Geographical Information Systems tools to process the DEM, a detailed drainage network was obtained, the areas of detected water erosion were separated, and the watersheds in the gullies identified. Subsequently, an estimated DEM before the erosive processes was reconstructed by interpolating the gully ridges; this DEM serves as a reference for the relief before the erosion. To calculate the volume of eroded material, the DEM of Differences was calculated, which estimates the volume difference between the previously estimated DEM and the current DEM. Additionally, we calculated the material necessary for the geomorphological adaptation of the quarry and the slope map, which are two valuable factors closely related to the monitoring of erosive processes. The results obtained allowed us to identify the erosion factors quickly and accurately in this type of mining. In the case of water-filled quarries, it would be important to characterize the subsurface relief. Essentially, the presented method can be applied with affordable and non-invasive materials to create digital grid maps at 10 cm resolution, obtaining data ready for 3D metrics, being a very practical landscape modelling tool for characterizing the restoration evolution of open-pit mining spaces

Millora del tractament de les imatges captades pels satèl·lits Landsat-8 i Sentinel-2 mitjançant espectroradiometria de camp i sensors embarcats en Vehicles Aeris no Tripulats (UAV)

La irrupció tecnològica dels Vehicles Aeris no Tripulats (UAV o drons) com a noves plataformes de teledetecció, està fent evolucionar la Geografia cap a una nova escala d’observació de la Terra. Mitjançant diferents instruments de captació de dades (e.g. satèl·lits, aeronaus), actualment es poden monitoritzar i analitzar quantitativament diversos fenòmens que afecten la superfície terrestre a diferents escales, així com els seus canvis. Convencionalment, la validesa de les mesures de teledetecció satel·litària es comprova mitjançant el seu ajust respecte de mesures in-situ captades amb espectroradiòmetres de camp o mitjançant la inter-comparació entre sensors satel·litaris. De fet, és necessari corregir radiomètricament les imatges de satèl·lit per obtenir dades el més similars possible a les que s’obtindrien a nivell de superfície terrestre i que siguin coherents entre diferents sensors. No obstant, encara hi ha un salt d’escala molt gran entre l’adquisició de dades de camp i les dades satel·litàries o aèries convencionals, fet que en complica la validació in-situ. La principal hipòtesi d’aquesta recerca és que els UAV poden omplir el buit d'escala entre imatges de satèl·lit i mesures in-situ convencionals, millorant així la correcció radiomètrica d’imatges satel·litàries. L’objectiu d’aquesta recerca és introduir l’ús de dades captades amb UAV, en sinergia amb dades espectroradiomètriques de camp, per complementar i millorar el tractament radiomètric de les imatges captades pels satèl·lits Landsat-8 i Sentinel-2, vinculant així observacions sobre el terreny (espectroradiometria de camp), observacions a escala local (UAV) i observacions a escala global (satèl·lits), obtenint més solidesa, continuïtat i coherència en les dades d’observació de la Terra a totes les escales. A diferència dels satèl·lits, els drons tenen la característica de volar a molt baixa altura (e.g. menys de 120 m, segons la llei espanyola actual), de manera que les imatges captades pels seus sensors tenen molt més detall espacial (e.g. 10 cm per píxel) i pràcticament no estan influenciades per l’atmosfera. D’altra banda, les tècniques convencionals d’espectroradiometria de camp presenten dificultats operatives vinculades a la georeferenciació i remostreig espacial de les dades, la lentitud en la captura de mesures o la dificultat d’accedir a determinades cobertes del sòl. Així, la hipòtesi d’aquesta recerca contempla que l’ús de drons permet mostrejar una àrea molt més gran, de manera molt més ràpida, més sistemàtica, amb més detall i amb una més acurada georeferenciació que l’espectroradiometria de camp convencional, però amb una exactitud radiomètrica útil per als nostres propòsits de fer de pont entre les dades dels espectroradiòmetres de mà i les dades de satèl·lit. Per aconseguir-ho, a partir d’imatges captades amb sensors a bord d’UAV i calibrades al seu torn mitjançant dades de reflectància mesurades in-situ, s’obtenen referències radiomètriques per validar i/o corregir imatges de satèl·lit, contribuint així a introduir una nova capa de dades entre l’escala in-situ i l’escala satel·litària. En conclusió, en aquesta Tesi es fa una anàlisi de diversos mètodes de correcció radiomètrica d’imatges de satèl·lit i es validen mitjançant dades espectroradiomètriques de camp, però, addicionalment, es millora el tractament radiomètric de les dades satel·litàries mitjançant la introducció de dades captades amb drons. El mètode innova amb l’establiment de sinergies entre dades de radiometria de camp, dades de dron i dades satel·litàries, vinculant diferents escales de treball d’una manera eficient i millorada respecte els antecedents. En futures recerques, es preveu aplicar el mètode desenvolupat però utilitzant sensors per drons amb una configuració espectral més ajustada a la configuració dels sensors satel·litaris, i també fent vols coordinats de diversos drons al moment de pas dels satèl·lits. S’albira que aquesta recerca contribuirà a obtenir sèries temporals d’imatges molt més coherents que les obtingudes fins ara, assolint una informació més acurada de l’estat i l’evolució d’àrees protegides d’alt interès ecosistèmic local i global en tot el planeta.La irrupción tecnológica de los Vehículos Aéreos no Tripulados (UAV o drones) como nuevas plataformas de teledetección, está haciendo evolucionar la Geografía hacia una nueva escala de observación de la Tierra. Mediante diferentes instrumentos de captación de datos (p. ej. satélites, aeronaves), actualmente se pueden monitorizar y analizar cuantitativamente varios fenómenos que afectan la superficie terrestre a diferentes escalas, así como sus cambios. Convencionalmente, la validez de las medidas de teledetección satelital se comprueba mediante su ajuste respecto de medidas in-situ captadas con radiómetros de campo o mediante la inter-comparación entre sensores satelitales. De hecho, es necesario corregir radiométricamente las imágenes de satélite para obtener datos lo más similares posible a los que se obtendrían a nivel de superficie terrestre y que sean coherentes entre diferentes sensores. Sin embargo, todavía hay un salto de escala muy grande entre la adquisición de datos de campo y los datos satelitales o los datos aéreos convencionales, lo que complica la validación in-situ. La principal hipótesis de esta investigación es que los UAV pueden llenar el hueco de escala existente entre las imágenes de satélite y las medidas in-situ convencionales, mejorando así la corrección radiométrica de imágenes satelitales. El objetivo de esta investigación es introducir el uso de datos captados con UAV, en sinergia con datos radiométricos de campo, para complementar y mejorar el tratamiento radiométrico de las imágenes captadas por los satélites Landsat-8 y Sentinel-2, vinculando así observaciones sobre el terreno, observaciones a escala local (UAV) y observaciones a escala global (satélites), obteniendo más solidez, continuidad y coherencia en los datos de observación de la Tierra en todas las escalas. A diferencia de los satélites, los drones tienen la característica de volar a muy baja altura (p. ej. menos de 120 m), de modo que las imágenes captadas por sus sensores tienen mucho más detalle espacial (p. ej. 10 cm por píxel) y prácticamente no están influenciadas por la atmósfera. Por otra parte, las técnicas convencionales de radiometría de campo presentan dificultades operativas vinculadas a la georreferenciación y remuestreo espacial de los datos, la lentitud en la toma de medidas o la dificultad de acceder a determinadas cubiertas del suelo. Así, la hipótesis de esta investigación contempla que el uso de drones permite muestrear un área mucho mayor, de manera mucho más rápida, más sistemática, con más detalle y con una más cuidadosa georreferenciación que la radiometría de campo convencional, pero con una exactitud radiométrica útil para nuestros propósitos de hacer de puente entre los datos de los radiómetros de mano y lo datos satelitales. Para ello, a partir de imágenes captadas con sensores a bordo de UAV y calibradas a su vez mediante datos de reflectancia medidos in-situ, se obtienen referencias radiométricas para validar y/o corregir imágenes de satélite, contribuyendo así a introducir una nueva capa de datos entre la escala in-situ y la escala satelital. En conclusión, en esta Tesis se hace un análisis de diversos métodos de corrección radiométrica de imágenes de satélite y se validan mediante datos radiométricos de campo, pero, adicionalmente, se mejora el tratamiento radiométrico de los datos satelitales mediante la introducción de datos captados con drones. El método innova con el establecimiento de sinergias entre datos de radiometría de campo, datos de dron y datos satelitales, vinculando diferentes escalas de trabajo de una manera eficiente y mejorada respecto a los antecedentes. En futuras investigaciones, se prevé aplicar el método desarrollado pero utilizando sensores para drones con una configuración espectral más ajustada a la configuración de los sensores satelitales. Se vislumbra que esta investigación contribuirá a obtener series temporales de imágenes mucho más coherentes que las obtenidas hasta ahora, logrando una información más detallada del estado y la evolución de áreas protegidas de alto interés ecosistémico local y global en todo el planeta.The technological breakthrough of Unmanned Aerial Vehicles (UAV or drones) as new remote sensing platforms is making Geography evolve towards a new scale of Earth observation. By using different data capture instruments (e.g. satellites, aircrafts), several phenomena that affect the Earth's surface as well as its changes, can currently be monitored and analyzed quantitatively at different scales. Conventionally, the validity of the satellite remote sensing measures is checked by the fitting to in-situ measurements captured with field spectrometers or by inter-comparison between satellite sensors. In fact, it is necessary to radiometrically correct the satellite images to obtain the most similar data to those that would be obtained at ground level and, moreover, to obtain coherent data between different satellite sensors. However, there is still a very large-scale gap between the acquisition of field data and satellite data or manned airborne data, which complicates the in-situ validation. The main hypothesis of this research is that the UAV can fill the gap between satellite images and conventional in-situ measurements, thus improving the radiometric correction of satellite imagery. The aim of this research is to introduce the use of data captured with UAV, in synergy with field spectroradiometric data, to complement and improve the radiometric treatment of the images captured by the Landsat-8 and Sentinel-2 satellites, linking field observations (field spectroradiometry), observations at the local scale (UAV) and observations at the global scale (satellites), obtaining more solidity, continuity and coherence in the Earth observation data at all scales. Unlike satellites, drones have the characteristic of flying at a very low altitude (e.g. less than 120 m, in compliance with current drone regulations in Spain), so that the images captured by their sensors have much more spatial detail (e.g. 10 cm per pixel) and are practically not influenced by the atmosphere. On the other hand, the conventional techniques of field spectroradiometry present operational difficulties linked to data georeferencing and spatial resampling, the slowness on the capture of measures or the difficulty of accessing certain land covers. Thus, the hypothesis of this research considers that the use of drones allows sampling a much larger area, much faster, more systematically, in more detail and with a more accurate georeferencing than conventional field spectroradiometry, but with a radiometric accuracy useful for our purposes of filling the gap between the field spectroradiometric data and the satellite data. To achieve this goal, from images captured with sensors on board of UAV and calibrated in turn by means of in-situ measured reflectance data, radiometric references are obtained to validate and/or correct satellite images, contributing towards introducing a new data layer between the in-situ scale and the satellite scale. In conclusion, this PhD thesis not only analyzes several radiometric correction methods of satellite images that are validated using field spectroradiometric data but also it supports measures for improving radiometric treatment of satellite data by introducing data captured with drones. The method innovates by establishing synergies between field spectroradiometric data, drone data and satellite data, linking different geographical scales in an efficient and improved way with respect to the antecedents. Future research will focus on applying the developed method by using drone-embedded sensors with spectral settings that better fits the satellite sensors features, and planning coordinated flights of several drones at the satellite overpass. This research will contribute towards obtaining more coherent image time series than in previous works, by achieving more accurate information on the state and the evolution of protected areas of high local and global ecosystem interest throughout the planet