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To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 1 foot cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary. |
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To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 1 foot cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary. |
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County of Santa Clara; Sanborn Map Company. |
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<DIV STYLE="text-align:Left;font-size:12pt"><P><SPAN>Product: These are one foot contour data as part of the required deliverables for the lidar project. Also delivered were 5, 10, and 25 foot contour subsets. Geographic Extent: Alameda, Merced, Monterey, San Benito, San Joaquin, San Mateo, Santa Clara, Santa Cruz, and Stanislaus counties, California, covering approximately 1769 square miles. Dataset Description: The lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification. The data was developed based on a horizontal projection/datum of NAD83(2011) California Zone 3, Feet and vertical datum of NAVD88 (GEOID18), Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 8185 individual 2500 ft x 2500 ft tiles clipped to the DPA, as tiled intensity images, as tiled DTMs, as tiled DEMs, and as tiled DSMs; all tiled to the same 2500 ft x 2500 ft schema. Ground Conditions: Lidar was collected in late 2022, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Sanborn Map Company, Inc., established a total of 42 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 129 independent accuracy check points, 74 in bare earth and urban landcovers (74 NVA points), 55 in tall grass and brushland/low trees categories (55 VVA points), were used to assess the vertical accuracy of the data. These check points were not used to calibrate or post process the data.</SPAN></P></DIV> |
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<DIV STYLE="text-align:Left;font-size:12pt"><P><SPAN>None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.</SPAN></P></DIV> |
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Contour 5ft - Lidar 2023 |
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["Contours","Lidar","Santa Clara County","sccgov"] |
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en-US |
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0 |
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