The primary goal is to describe the state-of-the-art for a typical digital terrain modeling workflow that starts with data capture, continues with data preprocessing and DEM generation, and concludes with the calculation of one or more primary and secondary land surface parameters. This book examines how the methods and data sources used to generate DEMs and calculate land surface parameters have changed over the past 25 years. It is usual to use a network that creates sloping triangles or regular quadrants. It would take an endless number of points to describe exactly the random terrain shapes, but these can be described in practice with a network of point. The random (stochastic) elements are the continuous surfaces with continuously varying relief. The terrain surface can be described as compromising of two different elements random and systematic. DEMs are used often in geographic information systems, and are the most common basis for digitally-produced relief maps. DEMs are commonly built using remote sensing techniques, but they may also be built from land surveying. A DEM can be represented as a raster (a grid of squares) or as a vector based triangular irregular network (TIN). It is also widely known as a digital terrain model (DTM). A digital elevation model (DEM) is a digital representation of ground surface topography or terrain.
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