971 resultados para Land cover classification


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This layer is a georeferenced raster image of the historic paper map entitled: Mapa de la isla de Lanzarote, por Don Tomás Lopez, geografo de los dominios de S. M., de las Reales academias de la historia, de San Fernando, de la de buenas letras de Sevilla y de la Sociedad Bascongada de los amigos del pais. It was published by se hallará este con todas las obras del autor en la Calle de las Carretas entrando por la Plazuela del Angel in 1779. Scale [ca. 1:280,000]. Covers Isla de Lanzarote, Canary Islands, Spain. Map in Spanish.The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Mercator projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, land cover, villages and other human settlements, roads, shoreline features, ports and anchorage points, and more. Relief shown by hachures. Includes note on the mapping of Lanzarote and inset map: Mapa de la isla de del Hierro.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: Mapa de la isla de Tenerife, por Don Tomás Lopez, geografo de los dominios de S. M., de las Reales academias de la historia, de San Fernando, de la de buenas letras de Sevilla y de la Sociedad Bascongada de los amigos del pais. It was published by se hallará este con todas las obras del autor en la Calle de las Carretas entrando por la Plazuela del Angel in 1779. Scale [ca. 1:280,000]. Covers Isla de Tenerife, Canary Islands, Spain. Map in Spanish.The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Mercator projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, land cover, cities and towns, villages and other human settlements, fortification and watch towers, roads, shoreline features, ports and anchorage points, and more. Relief shown by hachures. Includes note on the mapping of Tenerife.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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This layer is a georeferenced raster image of the historic paper map entitled: Juta's map of South Africa from the Cape to the Zambesi, compiled from the best available Colonial and Imperial information including the official Cape Colony map by the Surveyor General, Cape Town, Dr. T. Hahn's Damaraland, and F.C. Selous' journals and sketches ; published by J.C. Juta & Co. It was published by J.C. Juta : Edward Stanford. in 1897. Scale [ca. 1:2,534,400]. Covers Southern Africa. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Africa Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial and administrative boundaries, shoreline features, roads, railroads, mines, and more. Relief shown by hachures. Includes also notes about land cover.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

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Identifying cloud interference in satellite-derived data is a critical step toward developing useful remotely sensed products. Most MODIS land products use a combination of the MODIS (MOD35) cloud mask and the 'internal' cloud mask of the surface reflectance product (MOD09) to mask clouds, but there has been little discussion of how these masks differ globally. We calculated global mean cloud frequency for both products, for 2009, and found that inflated proportions of observations were flagged as cloudy in the Collection 5 MOD35 product. These erroneously categorized areas were spatially and environmentally non-random and usually occurred over high-albedo land-cover types (such as grassland and savanna) in several regions around the world. Additionally, we found that spatial variability in the processing path applied in the Collection 5 MOD35 algorithm affects the likelihood of a cloudy observation by up to 20% in some areas. These factors result in abrupt transitions in recorded cloud frequency across landcover and processing-path boundaries impeding their use for fine-scale spatially contiguous modeling applications. We show that together, these artifacts have resulted in significantly decreased and spatially biased data availability for Collection 5 MOD35-derived composite MODIS land products such as land surface temperature (MOD11) and net primary productivity (MOD17). Finally, we compare our results to mean cloud frequency in the new Collection 6 MOD35 product, and find that landcover artifacts have been reduced but not eliminated. Collection 6 thus increases data availability for some regions and land cover types in MOD35-derived products but practitioners need to consider how the remaining artifacts might affect their analysis.

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"Other copies of this report may bear the number NRL-O-2982"--Page 2 of cover.

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"The Y-12 Plant of the Clinton Engineer Works was operated by the Tennessee Eastman Corporation under Contract No. W-7401-eng-23 from Januaury 1943 until May 4, 1947, at which time operations were taken over by Carbide and Carbon Chemicals Corporation for the U.S. Atomic Energy Commission under Contract No. W-7405-eng-26"--Page 2 of cover.

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"The Mackinaw River Area Assessment examines an area situated along the Mackinaw River in the central part of Illinois. Because significant natural community and species diversity is found in the area, it has been designated a state Resource Rich Area. This report is part of a series of reports on Illinois Resource Rich Areas where a public-private partnership has been formed. These assessments provide information on the natural and human resources of the areas as a basis for managing and improving their ecosystems. The determination of resource rich areas and development of ecosystem-based information and management programs in Illinois are the result of three processes -- the Critical Trends Assessment Program, the Conservation Congress, and the Water Resources and Land Use Priorities Task Force."--P. iii, v.1.

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U.S. Geological Survey, Department of Interior Cooperative Agreement No. 14-48-0003-95-1090

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4 leaves in pocket on p. [3] of cover.

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Increasingly, large areas of native tropical forests are being transformed into a mosaic of human dominated land uses with scattered mature remnants and secondary forests. In general, at the end of the land clearing process, the landscape will have two forest components: a stable component of surviving mature forests, and a dynamic component of secondary forests of different ages. As the proportion of mature forests continues to decline, secondary forests play an increasing role in the conservation and restoration of biodiversity. This paper aims to predict and explain spatial and temporal patterns in the age of remnant mature and secondary forests in lowland Colombian landscapes. We analyse the age distributions of forest fragments, using detailed temporal land cover data derived from aerial photographs. Ordinal logistic regression analysis was applied to model the spatial dynamics of mature and secondary forest patches. In particular, the effect of soil fertility, accessibility and auto-correlated neighbourhood terms on forest age and time of isolation of remnant patches was assessed. In heavily transformed landscapes, forests account for approximately 8% of the total landscape area, of which three quarters are comprised of secondary forests. Secondary forest growth adjacent to mature forest patches increases mean patch size and core area, and therefore plays an important ecological role in maintaining landscape structure. The regression models show that forest age is positively associated with the amount of neighbouring forest, and negatively associated with the amount of neighbouring secondary vegetation, so the older the forest is the less secondary vegetation there is adjacent to it. Accessibility and soil fertility also have a negative but variable influence on the age of forest remnants. The probability of future clearing if current conditions hold is higher for regenerated than mature forests. The challenge of biodiversity conservation and restoration in dynamic and spatially heterogeneous landscape mosaics composed of mature and secondary forests is discussed. (c) 2004 Elsevier B.V. All rights reserved.

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Tropical deforestation is the major contemporary threat to global biodiversity, because a diminishing extent of tropical forests supports the majority of the Earth's biodiversity. Forest clearing is often spatially concentrated in regions where human land use pressures, either planned or unplanned, increase the likelihood of deforestation. However, it is not a random process, but often moves in waves originating from settled areas. We investigate the spatial dynamics of land cover change in a tropical deforestation hotspot in the Colombian Amazon. We apply a forest cover zoning approach which permitted: calculation of colonization speed; comparative spatial analysis of patterns of deforestation and regeneration; analysis of spatial patterns of mature and recently regenerated forests; and the identification of local-level hotspots experiencing the fastest deforestation or regeneration. The colonization frontline moved at an average of 0.84 km yr(-1) from 1989 to 2002, resulting in the clearing of 3400 ha yr(-1) of forests beyond the 90% forest cover line. The dynamics of forest clearing varied across the colonization front according to the amount of forest in the landscape, but was spatially concentrated in well-defined 'local hotspots' of deforestation and forest regeneration. Behind the deforestation front, the transformed landscape mosaic is composed of cropping and grazing lands interspersed with mature forest fragments and patches of recently regenerated forests. We discuss the implications of the patterns of forest loss and fragmentation for biodiversity conservation within a framework of dynamic conservation planning.

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Landscape change occurs through the interaction of a multitude of natural and human driving forces at a range of organisational levels, with humans playing an increasingly dominant role in many regions of the world. Building on the current knowledge of the underlying drivers of landscape change, a conceptual framework of regional landscape change was developed which integrated population, economic and cultural values, policy and science/technology. Using the Southern Brigalow Belt biogeographic region of Queensland as a case study, the role of natural and human drivers in landscape change was investigated in four phases of settlement since 1840. The Brigalow Belt has experienced comparable rates of vegetation clearance over the past 50 years to areas of tropical deforestation. Economic factors were important during all phases of development, but the five regional drivers often acted in synergy. Environmental constraints played a significant role in slowing rates of change. Temporal trends of deforestation followed a sigmoidal curve, with initial slow change accelerating though the middle phases then slowing in recent times. Future landscape management needs to take account of the influence of all the components of the conceptual framework, at a range of organisational levels, if more ecologically sustainable outcomes are to be achieved. (c) 2006 Elsevier B.V. All rights reserved.