Revista de Teledetección - Núm. 43 (2015)
Tabla de contenidos
- Editorial
Research articles
- Mapping of fuels and fire potentials in the African Continent using FCCS
- Implications of quality filtering of Enhanced Vegetation Index (EVI) for ecosystem functioning monitoring
- Study of the NDVI with multi-scale and time-series analysis using SPOT imagery during the period 1998-2012 in Uruguay
- Monitoring the latent and sensible heat fluxes in vineyard by applying the energy balance model METRIC
- Towards a long-term dataset of ELBARA-II measurements assisting SMOS level-3 land product and algorithm validation at the Valencia Anchor Station
- Change detection in land use from unsupervised classifications for updating SIOSE. Implementation in Galicia
Practical cases
- Description and extraction of urban fragmentation indices: The Indifrag tool
- Application of the Mean-shift Segmentation Parameters Estimator (MSPE) to VHSR satellite images: Tetuan-Morocco
Doctoral theses
- Extraction of shorelines with sub-pixel precision from Landsat images (TM, ETM+, OLI)
URI permanente para esta colecciónhttps://riunet.upv.es/handle/10251/80561
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Item type: Reseña , Access status: Abierto , Obtención de línea de costa con precisión sub-píxel a partir de imágenes Landsat (TM, ETM+ y OLI)(Universitat Politècnica de València, 2015-06-26) Almonacid-Caballer, J.[EN] This thesis presents and evaluate a methodology for automatic extraction of shorelines with sub-pixel precision from Landsat 5, 7 and 8 images acquired by sensors TM, ETM+ and OLI, respectivelyItem type: Artículo , Access status: Abierto , Application of the Mean-shift Segmentation Parameters Estimator (MSPE) to VHSR satellite images: Tetuan-Morocco(Universitat Politècnica de València, 2015-06-26) Benarchid, O.; Raissouni, N.; Sobrino, J.A.; El Ayyan, A.; Ministère de l'Education Nationale, de la Formation professionnelle, de l'Enseignement Supérieur et de la Recherche Scientifique, Marruecos; European Commission[EN] Image segmentation is considered as crucial step dealing with Object-Based Image Analysis (OBIA) and different segmentation results could be achieved by combining possible parameters values. Optimal parameters selection is usually carried out on the basis of visual interpretation; therefore, defining optimal combinations is a challenging task. In the present research, Mean-shift Segmentation Parameters estimator (MSPE) proposed tool is applied to automate the selection of segmentation parameters values to Very High Spatial Resolution (VHSR) satellite images in the region of Tetuan city (Northern Morocco). MSPE estimates the parameters values for the Mean-shift Segmentation (MS) algorithm. However, this algorithm needs as inputs: i) existing vector database and, ii) spectral data to define automatically the segmentation parameter values. Finally, application of the MSPE method on different landscape’ types show accurate results with Under-Segmentation (US) values ≤0.20 for industrial, residential and rural zones, while for dense residential area values of 0.35.Item type: Artículo , Access status: Abierto , Description and extraction of urban fragmentation indices: The Indifrag tool(Universitat Politècnica de València, 2015-06-26) Sapena, M.; Ruiz, L.A.[EN] The concept of land fragmentation is studied and analysed in this paper by means of remote sensing and GIS techniques. A new tool is presented, IndiFrag, which calculates a variety of metrics to characterise landscape fragmentation using as input data LULC classification data in vector format. The tool includes an exhaustive set of fragmentation indices, and allows its application to cartographic objects at several hierarchical levels. These indices are divided into five groups according to the measured properties: area and perimeter, shape, aggregation, diversity, and contrast. The tool and methods are applied to data derived from an object-based classification and neighbourhood boundaries from the city of Valencia, in order to assess the urban use fragmentation. Urban fragmentation indices and maps of the Valencian administrative neighbourhoods are generated and interpreted. The development of IndiFrag constitutes a preliminary step to create a methodology that quantifies urban evolution through the time in terms of fragmentation, as well as to explore the relations from a geographical perspective. Guardar / Salir Siguiente >Item type: Artículo , Access status: Abierto , Change detection in land use from unsupervised classifications for updating SIOSE. Implementation in Galicia(Universitat Politècnica de València, 2015-06-26) Vila-García, D.; Gil-Docampo, M.L.; Iniesto-Alba, M.J.[EN] One of the basic elements when designing policy analysis, management and land use planning is a good land use mapping. For this purpose, there is the Corine Land Cover (CLC) at European level and SIOSE (Occupation Information System Soil Spain) nationwide. Processes updating of this cartography are often costly, and this is where the techniques of remote sensing of the Earth can be of great help. This work is to obtain, through a multi-temporal analysis between SPOT 5 images of 2009 and 2011, an effective method of detecting changes in a heterogeneous level of coverage as the Galician field. To achieve the identification of areas where there has been modification of land uses, new channels that collect differences (radiometric and structural) from SPOT images for both years are generated. Then, several classifications are made in these channels obtaining a layer changes. This layer changes supported with images PNOA (National Aviation Plan Orthophotography) is a reliable and useful information for a directed photointerpretation in SIOSE update, thereby reducing the execution time and maintaining the quality of the final database.Item type: Artículo , Access status: Abierto , Towards a long-term dataset of ELBARA-II measurements assisting SMOS level-3 land product and algorithm validation at the Valencia Anchor Station(Universitat Politècnica de València, 2015-06-26) Fernandez-Moran, R.; Wigneron, J. P.; López-Baeza, E.; Miernecki, M.; Salgado-Hernanz, P.; Coll, M.A.; Kerr, Y. H.; Schwank, M.; Ministerio de Economía y Competitividad[EN] The Soil Moisture and Ocean Salinity (SMOS) mission was launched on 2nd November 2009 with the objective of providing global estimations of soil moisture and sea salinity. The main activity of the Valencia Anchor Station (VAS) is currently to assist in a long-term validation of SMOS land products. This study focus on a level 3 SMOS data validation with in situ measurements carried out in the period 2010-2012 over the VAS. ELBARA-II radiometer is placed in the VAS area, observing a vineyard field considered as representative of a major proportion of an area of 50×50 km, enough to cover a SMOS footprint. Brightness temperatures (TB) acquired by ELBARA-II have been compared to those observed by SMOS at the same dates and time. They were also used for the L-MEB model inversion to retrieve soil moisture (SM), which later on have been compared to those provided by SMOS as level 3 data. A good correlation between both TB datasets was found, improving year by year, mainly due to the decrease of precipitations in the analyzed period and the mitigation of radio frequency interferences at L-band. The larger homogeneity of the radiometer footprint as compared to SMOS explains the higher variability of its TB. Periods of more intense precipitation (spring and autumn) also presented higher SM, which corroborates the consistency of SM retrieved from ELBARA-II’s observations. However, the results show that SMOS level 3 data underestimate SM as compared to ELBARA-II’s, probably due to the influence of the small soil fraction which is not cultivated in vineyards. SMOS estimations in descending orbit (6 pm) had better quality (higher correlation, lower RMSE and bias) than the ones in ascending orbit (6 am, when there is a higher soil moisture). Guardar / Salir Siguiente >Item type: Artículo , Access status: Abierto , Monitoring the latent and sensible heat fluxes in vineyard by applying the energy balance model METRIC(Universitat Politècnica de València, 2015-06-26) González-Piqueras, J.; Villodre, J.; Campos, I.; Calera, A.; Balbontín, C.; Ministerio de Ciencia e Innovación; Fondo Nacional de Desarrollo Científico y Tecnológico, Chile[EN] The monitoring of the energy fluxes over vineyard applying the one source energy balance model METRIC (Allen et al., 2007b) are shown in this work. This model is considered operaive because it uses an internalized calibration method derived from the selection of two extreme pixels in the scene, from the minimum ET values such as the bare soil to a maximum that corresponds to full cover active vegetation. The model provides the maps of net radiation (Rn), soil heat flux (G), sensible heat (H), latent heat (LE), evapotranspiration (ET) and crop coefficient (Kc). The flux values have been validated with a flux tower installed in the plot, providing a RMSE for instantaneous fluxes of 43 W m2, 33 W m2, 55 W m2 y 40 W m2 on Rn, G, H and LE. In relative terms are 8%, 29%, 21% and 20% respectively. The RMSE at daily scale for the ET is 0.58 mm day-1, with a value in the crop coefficient for the mid stage of 0.42±0.08. These results allow considering the model adequate for crop monitoring and irrigation purposes in vineyard. The values obtained have been compared to other studies over vineyard and with alternative energy balance models showing similar results. Guardar / Salir Siguiente >Item type: Artículo , Access status: Abierto , Study of the NDVI with multi-scale and time-series analysis using SPOT imagery during the period 1998-2012 in Uruguay(Universitat Politècnica de València, 2015-06-26) Ceroni, M.; Achkar, M.; Gazzano, I.; Burgeño, J.; Comisión Sectorial de Investigación Científica, Uruguay[EN] Vegetation indices are a relevant source of information for spatial monitoring of vegetation at multiple scales. Among them, the Normalized Difference Vegetation Index (NDVI) is one of the most commonly used. This study aims to describe and analyze the spatial patterns of the NDVI in terrestrial systems in Uruguay at the onset of the 21st Century. A multiscalar approach (country, basin and sites) was applied using time series analysis of NDVI values obtained from SPOT 4 and 5 images through the program Instrument Vegetation (VGT). The analyzed time series showed a significant fit of the Autocorrelated Integrated Moving Averages (ARIMA) model, with an autocorrelation of order 2 and a level of integration of order 1, ARIMA (211). A significant decline of the NDVI over all spatial units was found, with agricultural units (site scale) showing the most negative slope. This study provides baseline data on changes in vegetation productivity for Uruguay, and develops an accurate and robust methodology for spatio-temporal analysis of NDVI series. Remote sensing techniques are shown to be relevant to improve the management of environmental systems.Item type: Artículo , Access status: Abierto , Implications of quality filtering of Enhanced Vegetation Index (EVI) for ecosystem functioning monitoring(Universitat Politècnica de València, 2015-06-26) Reyes-Díez, A.; Alcaraz-Segura, D.; Cabello-Piñar, J.; Ministerio de Ciencia e Innovación; Junta de Andalucía; Centro Andaluz para la Evaluación y Seguimiento del Cambio Global[EN] The use of MODIS (Moderate Resolution Imaging Spectroradiometer) images for ecosystem monitoring is currently widespread both in research and management. Vegetation indexes (VIs), such as NDVI (Normalized Difference Vegetation Index) and EVI (Enhanced Vegetation Index), are broadly extended for monitoring ecosystem functioning. These indexes are linear estimators of the fraction of photosynthetically active radiation intercepted by vegetation (fAPAR), the main control of net primary production. However, VIs are subject to errors. To handle such errors, the MOD13Q1 VI product includes a Quality Assessment (QA) layer with information about pixel quality. This QA layer represents a great advantage for final users, allowing filtering of pixels with VI values influenced by aerosols, clouds, snow, or shadows. However, the use of homogeneous filtering criteria throughout a heterogeneous region may cause the systematic loss of information in particular areas or times of the year. In this paper, we assessed the effect of different filtering criteria on spatiotemporal data of EVI for the period 2001-2010 in the Iberian Southeast. Our results showed no effect of filtering on EVI availability and magnitude values in low altitudes, but strong and significant differences in the mountains depending on the filter applied: aerosol, shadows or snow filters. Such effects of filtering on the EVI revealed that monitoring programs in these regions should include a filtering step before exploring for abrupt changes or longterm trends in the EVI time series.Item type: Artículo , Access status: Abierto , Mapping of fuels and fire potentials in the African Continent using FCCS(Universitat Politècnica de València, 2015-06-26) Pettinari, M.L.; Chuvieco, E.; Ministerio de Ciencia e Innovación; Ministerio de Educación, Chile; Fondo Nacional de Desarrollo Científico y Tecnológico, Chile[EN] This paper presents the methodology used for the development of a fuel map for the African Continent, using FCCS (Fuel Characteristic Classification System). The cartography of the fuelbeds was based on global cartographic information obtained from remote sensing imaging, and the variables associated to each fuelbed were extracted from existing vegetation databases. A total of 75 fuelbeds were developed, and from the variables assigned to each of them, different Fire Potentials were calculated using default environmental variables. These potentials allow the estimation of surface fire behavior, crown fire and available fuel, depending on the characteristics of the existing vegetation.