954 resultados para contour map
Resumo:
Topographic data of this geological map were obtained through stereoscopic aerial photo interpretation. The photogrammetric photo flights were undertaken in 1986 by the Institut für Angewandte Geodäsie, Frankfurt. Horizontal ground control points required for aerial photo interpretation were determined by means of Doppler satellite observation during the 2nd German Neuschwabenland Expedition 1985/86. Vertical ground control points were taken from unpublished map drafts at 1:100 000 scale by Norsk Polarinstitutt, Oslo. The elevation above mean sea level was transferred to Heimefrontfjella barometrically. For this reason assertions concerning the absolute elevation (referred to sea level) are uncertain. Contours and spot heights presented on the map were obtained from the photogrammetric evaluation of the photography taken in 1986; relative elevation data (hight differences) are accurate to approximately ±10 m.
Resumo:
Detailed knowledge of forest cover dynamics is crucial for many applications from resource management to ecosystem service assessments. Landsat data provides the necessary spatial, temporal and spectral detail to map and analyze forest cover and forest change processes. With the opening of the Landsat archive, new opportunities arise to monitor forest dynamics on regional to continental scales. In this study we analyzed changes in forest types, forest disturbances, and forest recovery for the Carpathian ecoregion in Eastern Europe. We generated a series of image composites at five year intervals between 1985 and 2010 and utilized a hybrid analysis strategy consisting of radiometric change classification, post-classification comparison and continuous index- and segment-based post-disturbance recovery assessment. For validation of the disturbance map we used a point-based accuracy assessment, and assessed the accuracy of our forest type maps using forest inventory data and statistically sampled ground truth data for 2010. Our Carpathian-wide disturbance map achieved an overall accuracy of 86% and the forest type maps up to 73% accuracy. While our results suggested a small net forest increase in the Carpathians, almost 20% of the forests experienced stand-replacing disturbances over the past 25 years. Forest recovery seemed to only partly counterbalance the widespread natural disturbances and clear-cutting activities. Disturbances were most widespread during the late 1980s and early 1990s, but some areas also exhibited extensive forest disturbances after 2000, especially in the Polish, Czech and Romanian Carpathians. Considerable shifts in forest composition occurred in the Carpathians, with disturbances increasingly affecting coniferous forests, and a relative decrease in coniferous and mixed forests. Both aspects are likely connected to an increased vulnerability of spruce plantations to pests and pathogens in the Carpathians. Overall, our results exemplify the highly dynamic nature of forest cover during times of socio-economic and institutional change, and highlight the value of the Landsat archive for monitoring these dynamics.
Resumo:
As an example for the representation of glaciers using orthophoto maps the new map "Langtaler Ferner 1971" is presented. The orthophoto map shows the glacier "Langtaler Ferner" in the Oetztal Alps (Austria) on August 18, 1971. Apart from a description of the map production and a discussion of the advantages and disadvantages of such ortho- photo maps for the representation of glacierized areas, the stage of the "Langtaler Ferner" at the time of the ftight is described. A comparison with some data of previollsly published maps is also included.
Resumo:
Spatial Data Infrastructures have become a methodological and technological benchmark enabling distributed access to historical-cartographic archives. However, it is essential to offer enhanced virtual tools that imitate the current processes and methodologies that are carried out by librarians, historians and academics in the existing map libraries around the world. These virtual processes must be supported by a generic framework for managing, querying, and accessing distributed georeferenced resources and other content types such as scientific data or information. The authors have designed and developed support tools to provide enriched browsing, measurement and geometrical analysis capabilities, and dynamical querying methods, based on SDI foundations. The DIGMAP engine and the IBERCARTO collection enable access to georeferenced historical-cartographical archives. Based on lessons learned from the CartoVIRTUAL and DynCoopNet projects, a generic service architecture scheme is proposed. This way, it is possible to achieve the integration of virtual map rooms and SDI technologies bringing support to researchers within the historical and social domains.