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Item Green area and vegetation cover indexes for Parral city (Chile) using Photointerpretation and GISAutores: Mena, C.; Ormazabal, Y.; Morales, Y.; Santelices, R.; Gajardo, J.he importance of the green areas is increasing since they are an important factor in the health and welfare of urban population. Therefore, in Parral city, in Central Chile, it was quantified and analyzed the availability of green areas and vegetation cover, using aerial photographs scale 1: 10000 and Geographic Information Systems (GIS). In a first stage, urban street trees were quantified through a simple random sample of twenty-four units with field measurements combined with measurements on aerial photographs, from which it was obtained the surface provided. Subsequently, through the creation of GIS layers, the surface of existing green areas and available open spaces were obtained. In addition, through supervised digital classification, the surface covered by urban forestry in private spaces was calculated. Quantity indexes show that Parral city currently has 12.72 ha of green areas, equivalent to 4.82 m(2)/hab, which implies a green area frequency of 0.022 m(2)/m(2). These values could be improved, if the available open space are incorporated and thereby reach 12.06 m(2) per inhabitant. In relation with availability indexes it was established that the average of accessibility to a green area is 327.2 m. Moreover, assuming a buffer of 200 m around the green areas, it was determined that there are 5160 houses with the basic service (56.4%). By incorporating the available open spaces, these values decrease significantly obtaining an average of accessibility to a green area of 213.7 m and coverage of basic service of 79.2%. Finally, it was estimated that the existing vegetation within the urban blocks (urban forest in private spaces) represents an important resource 17.8 times larger than urban street trees, so it should be considered within the municipal plans and policies.Item Cartografía local de áreas quemadas empleando teledetecciónAutores: Gajardo, J.; Mena, C.; Ormazabal, Y.; Morales, Y.Se realizó la cartografía de un incendio forestal, ocurrido en la localidad de San José de Mingre, comuna de San Javier, Región del Maule, durante la temporada 2003 - 2004. El estudio empleó una serie de índices, transformaciones y métodos multipaso, efectuados sobre datos de una imagen del sensor TM a bordo de la plataforma Landsat. En una primera fase, la metodología empleada incluyó las correcciones geométricas, radiométricas y atmosféricas de la imagen satelital para obtener medidas de reflectancia. Posteriormente, se calcularon índices (NDVI, BAI), y la transformación (ALME). Se discriminaron de forma muy clara las zonas que se encontraban quemadas para la extracción de pixels semillas, posteriormente se analizó la separabilidad espectral de cada banda. En una segunda fase, se emplearon los pixels semillas para introducirlos en el algoritmo de crecimiento que permitió cartografiar el incendio. La información (combustible quemado, fecha del siniestro, recursos empleados), así como las mediciones reales de la superficie y perímetro del incendio fueron proporcionadas por CONAF Región del Maule. Sobre estas mediciones se contrastaron los resultados obtenidos en el procesamiento de la imagen Landsat. Los resultados indican una fiabilidad global que oscila entre 70 y 95% para las diversas técnicas empleadas, con una amplia variedad entre los índices espectrales y el crecimiento de regiones. Las conclusiones muestran que es factible emplear métodos de cuantificación de área quemada basados en datos remotos, demostrando su utilidad en casos de incendios de gran magnitud y de difícil acceso en donde es inviableItem Characterization n the technoloy level of grapevine blocks in the sagrada familia county, ChileAutores: Mena, C.; Moreno, Y.; Ormazabal, Y.; Morales, Y.; Avila, C.; Bustos, O.The technology level (NT) related to the management of grapevine blocks in the Sagrada Familia county, Chile, was estimated from technical-productive variables and using geomatic techniques. A SPOTMaps color mosaic was used for the identification and delimitation of grapevines blocks and GPS (global positioning system) equipment was used to support field work. The administrative and technical information associated with each vineyard and its grapevines blocks was collected by means of field surveys, whose variables and alternatives were later evaluated by experts related to the vine-growing sector. The spatial distribution pattern of NT was represented by maps. Most of the grapevines blocks (59%) have a medium level (NT2) of technological implementation, while the remaining area is divided equally between high and low levels (NT1 and NT3), with 20 and 21% respectively, which denotes a process of technological transition leading to improvement of vineyard productivity.
