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This feature class represents 1-foot elevation contours. These data were generated as part of a broader vegetation and land cover mapping project for the... |
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This feature class represents 1-foot elevation contours. These data were generated as part of a broader vegetation and land cover mapping project for the... |
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Golden Gate National Parks Conservancy, Tukman Geospatial, Quantum Geospatial, Marin County Parks and Open Space District, National Park Service, California State Parks, Marin Water. |
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5000 |
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[] |
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<DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 0 0;"><SPAN>Contour generation from LiDAR point data required a thinning operation in order to reduce contour sinuosity. The thinning operation reduced point density where topographic change is minimal (i.e., flat surfaces) while preserving resolution where topographic change was present. Model key points were selected from the ground model every 20 feet with the spacing decreased in regions with high surface curvature. Generation of model key points eliminated redundant detail in terrain representation, particularly in areas of low relief, and provided for a more manageable dataset. Contours were produced through TerraModeler by interpolating between the model key points at even elevation increments. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>Elevation contour lines were then intersected with ground point density rasters and a confidence field was added to each contour line. Contours which crossed areas of high point density have high confidence levels, while contours which crossed areas of low point density have low confidence levels. Areas with low ground point density are commonly beneath buildings and bridges, in locations with dense vegetation, over water, and in other areas where laser penetration to the ground surface was impeded. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /></P><P><SPAN /></P></DIV></DIV></DIV> |
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| title:
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Marin County 2019 1-Foot Contour Lines |
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["lidar","contour","1 foot","topography"] |
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en-US |
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150000000 |
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