Application of remote sensing and GIS to locate priority intervention areas after wildland fires in Mediterranean systems: a case study from south-eastern Spain

2004 ◽  
Vol 13 (3) ◽  
pp. 241 ◽  
Author(s):  
J. Reyes Ruiz-Gallardo ◽  
Santiago Castaño ◽  
Alfonso Calera

Wildland fires are one of the major causes of ecosystem degradation, especially in semiarid climates, where the erosion hazard is high. The identification of potential erosion zones is typically difficult as it requires expensive field and laboratory work. This paper proposes a methodology based on remote sensing and GIS techniques, which permits speedy identification of erosional areas in a semi-automatic way, tested in a large burn scar in south-eastern Spain. Inputs were slope, aspect, and fire severity. In order to obtain the latter a new method has been proposed, based on the difference in NDVI between two images (acquired before and after the fire event). Combining these maps in a GIS, a Forest Intervention Priority map (FIP) is produced, which identifies areas of high erosion potential. Field work was conducted to assess the method. Results indicate that the applied methodology reliably predicted the extent of very severe fire and, further, was generally useful for identifying sites of significant erosion. Additional work is required to refine: (1) remotely sensed fire severity thresholds, particularly for other Mediterranean forest systems and substrate conditions; and (2) associated mapping tools for informing post-fire management applications.

Author(s):  
M. K. Tripathi ◽  
H. Govil ◽  
P. K. Champati ray ◽  
I. C. Das

<p><strong>Abstract.</strong> Landslides are very common problem in hilly terrain. Chamoli region of Himalaya is highest sensitive zone of the landslide hazards. The purpose of Chamoli landslide study, to observe the important terrain factors and parameters responsible for landslide initiation. Lithological, geomorphological, slope, aspect, landslide, drainage density and lineament density map generated in remote sensing and GIS environment. Data information of related geological terrain obtain through topographic maps, remote sensing images, field visits and geological maps. Geodatabases of all thematic layers prepared through digitization of topographic map and satellite imageries (LISS-III, LISS-IV &amp;amp; ASTER DEM). Integrated all thematic layers applying information value method under GIS environment to map the zonation of landslide hazard zonation map validation and verification completed by field visit. The landslide hazard zonation map classified in four classes very high, high, medium and low.</p>


2016 ◽  
Vol 31 (3) ◽  
pp. 282
Author(s):  
Mikael Timóteo Rodrigues ◽  
Lincoln Gehring Cardoso ◽  
Sérgio Campos ◽  
Bruno Timóteo Rodrigues ◽  
Zacarias Xavier de Barros

O objetivo principal desse trabalho é averiguar a atuação do software TerraView 4.2.2 desempenhando a classificação supervisiona por meio do padrão espectral em imagem Landsat 5, associada a comparação do uso da terra das bacias hidrográficas dos rios Lavapés e Capivara, inseridas no município de Botucatu/SP utilizando-se técnicas de sensoriamento remoto e geoprocessamento. As áreas de treinamento supervisionado foram definidas a partir de nove classes para bacia do Lavapés e sete para bacia do Capivara, fundamentais para o estudo e análise do uso e ocupação da terra, como mata, solo, culturas - agricultura, corpos d´água e malha urbana dentre outras classes encontradas. Tais áreas de treinamento supervisionado foram definidas por meio de polígonos que representaram as respectivas classes de uso e ocupação da terra, considerando a cor, brilho, padrão e textura emitida por cada pixel da imagem. A diferença de resultados entre as duas bacias avaliadas foi notória, onde a bacia do Capivara apresentou melhores resultados, seguramente por apresentar um número menor de classes de uso da terra e uma menor área urbana, assim causando menos confusões para o algoritmo. Outro fator evidente foi à clara diferença dos produtos derivados a partir da classificação gerada e posteriormente pós-classificados com o filtro majoritário (majority filter), onde sempre após a reclassificação a acurácia foi elevada, apresentado menos erros de omissão e comissão nas matrizes e suavização dos mapas classificados, com a eliminação de classes de 10 e 75 pixels por região, o que abrandou consideravelmente a estética dos mapas e consequentemente a diminuição de erros. PALAVRAS-CHAVE: Geoprocessamento, Sensoriamento Remoto, Processamento de Imagens, Uso do solo. BEHAVIOR TERRAVIEW SOFTWARE IN SUPERVISED CLASSIFICATION IN DIFFERENT WATERSHEDSABSTRACT: The main objective of this study is to ascertain the performance of the TerraView 4.2.2 software performing the classification oversees through the spectral pattern on Landsat 5, associated with comparing the land use of the Lavapés and Capivara’s watersheds, set in Botucatu/São Paulo using remote sensing and GIS. The areas of supervised training were set from nine classes for Lavapés watershed, and seven for Capivara watershed, fundamental for the study and analysis of the use and occupation of land as forest, soil, crops – Agriculture, Water Bodies and Mesh urban, found among other classes. Such areas of supervised training were defined by polygons representing the respective classes of use and occupation of land, considering the color, brightness, pattern and texture emitted by each pixel of the image. The difference in results between the two watersheds was evaluated notorious, where the Capivara watershed showed better results, surely by having a smaller number of land use classes and a smaller urban area, thus causing less confusion for the algorithm. Another obvious factor was the clear difference of products derived from the classification generated and subsequently post-classed with the majority filter, where ever after reclassification accuracy has always been high, presented less errors of omission and commission in the headquarters and smoothing of classified maps, with the elimination of 10 and 75 pixels per region classes, which greatly slowed the aesthetics of maps and therefore decrease errors.KEYWORDS: Geoprocessing, Remote Sensing, Image Processing, Use of the soil.


2015 ◽  
Vol 31 (2) ◽  
pp. 225-239 ◽  
Author(s):  
Khoboso Elizabeth Seutloali ◽  
Heinz Reinhard Beckedahl ◽  
Timothy Dube ◽  
Mbulisi Sibanda

2021 ◽  
Vol 30 (1) ◽  
pp. 171-181
Author(s):  
Al-Zahraa Mohsen ◽  
Monim Al-Jiboori ◽  
Yaseen Al-Timimi

The objective of this study was to estimate the height of roughness element (ZH) and zero-displacement length (Zd) for Baghdad city using remote sensing and GIS techniques and resources such as DEM, DSM, and shapefile. The difference between DEM and DSM produced digital height model which represents the height of the roughness element for the region, which was used to determine the zero-displacement height. The results showed that the variations in Zd values depend strongly on ZH. Rusafa had the highest Zd (15.8 m) while Dora had the lowest values (4.7 m). Thus, Baghdad city has medium density classification according to the results of Zd and ZH values.


Author(s):  
R. Vasundhara ◽  
◽  
S. Dharumarajan ◽  
Rajendra Hegde ◽  
S. Srinivas ◽  
...  

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