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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. |
| summary:
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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. |
| accessInformation:
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County of Santa Clara; Sanborn Map Company. |
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16812.1197753004 |
| typeKeywords:
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["Data","Service","Image Service","ArcGIS Server"] |
| description:
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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN STYLE="font-size:14pt">Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the lidar project. Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 1 foot hydro-flattened Raster DEM. </SPAN></P><P><SPAN STYLE="font-size:14pt">Geographic Extent: Santa Clara county, California, covering approximately 1771 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, Version 2.1. </SPAN></P><P><SPAN STYLE="font-size:14pt">The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, 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, as tiled intensity rasters, and as tiled bare-earth DEMs; all tiled to the same 2500 ft x 2500 ft schema. </SPAN></P><P><SPAN STYLE="font-size:14pt">Ground Conditions: Lidar was collected in early 2020, 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., utilized a total of 25 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. </SPAN></P><P><SPAN STYLE="font-size:14pt">An additional 125 independent accuracy checkpoints, 70 in Bare Earth and Urban landcovers (70 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><P><SPAN /></P></DIV></DIV></DIV> |
| licenseInfo:
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<DIV STYLE="text-align:Left;"><P STYLE="font-size:16ptmargin:7 0 7 0;"><SPAN STYLE="font-size:14pt">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><P STYLE="font-size:16ptmargin:7 0 7 0;"><SPAN STYLE="font-size:14pt">THE GIS DATA IS PROVIDED "AS IS". THE COUNTY MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OR MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE ACCURACY, COMPLETENESS, VALUE, QUALITY, VALIDITY, MERCHANTABILITY, SUITABILITY, AND CONDITION, OF THE GIS DATA. USER'S OF COUNTY'S GIS DATA ARE HEREBY NOTIFIED THAT CURRENT PUBLIC PRIMARY INFORMATION SOURCES SHOULD BE CONSULTED FOR VERIFICATION OF THE DATA AND INFORMATION CONTAINED HEREIN. SINCE THE GIS DATA IS DYNAMIC, IT WILL BY ITS NATURE BE INCONSISTENT WITH THE OFFICIAL COUNTY DATA. ANY USE OF COUNTY'S GIS DATA WITHOUT CONSULTING OFFICIAL PUBLIC RECORDS FOR VERIFICATION IS DONE EXCLUSIVELY AT THE RISK OF THE PARTY MAKING SUCH USE.</SPAN></P><P STYLE="font-size:16ptmargin:7 0 7 0;"><SPAN /></P><DIV><P><SPAN /></P></DIV></DIV> |
| catalogPath:
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| title:
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BareEarth_DEM_HydroFlattened_2020 |
| type:
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Image Service |
| url:
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https://mapservices.sccgov.org/arcgis |
| tags:
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["sccgov","Model","Raster","DEM","Remote Sensing","Elevation Data","Lidar"] |
| culture:
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en-US |
| name:
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BareEarth_DEM_HydroFlattened_2020 |
| guid:
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| minScale:
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537987.832809612 |
| spatialReference:
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NAD_1983_2011_StatePlane_California_III_FIPS_0403_Ft_US |