8 datasets found
  1. a

    Contours 2017 1ft Area 21

    • hub.arcgis.com
    • hub-cookcountyil.opendata.arcgis.com
    Updated Dec 5, 2019
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 21 [Dataset]. https://hub.arcgis.com/maps/cookcountyil::contours-2017-1ft-area-21
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 21. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  2. a

    Contours 2017 1ft Area 13

    • hub.arcgis.com
    • hub-cookcountyil.opendata.arcgis.com
    Updated Dec 5, 2019
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 13 [Dataset]. https://hub.arcgis.com/datasets/2108ac1b8a744146a46c6e5d70fa4d2b
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 13. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  3. d

    2017 Countywide LiDAR Point Cloud

    • catalog.data.gov
    • datasets.ai
    • +1more
    Updated Sep 1, 2022
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Lake County Illinois GIS (2022). 2017 Countywide LiDAR Point Cloud [Dataset]. https://catalog.data.gov/dataset/2017-countywide-lidar-point-cloud-638f8
    Explore at:
    Dataset updated
    Sep 1, 2022
    Dataset provided by
    Lake County Illinois GIS
    Description

    Click here to access the data directly from the Illinois State Geospatial Data Clearinghouse. These lidar data are processed Classified LAS 1.4 files, formatted to 2,117 individual 2500 ft x 2500 ft tiles; used to create Reflectance Images, 3D breaklines and hydro-flattened DEMs as necessary. Geographic Extent: Lake county, Illinois covering approximately 466 square miles. Dataset Description: WI Kenosha-Racine Counties and IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 2,117 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema. Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. 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. These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.Link Source: Illinois Geospatial Data Clearinghouse

  4. a

    Contours 2017 1ft Area 04

    • hub-cookcountyil.opendata.arcgis.com
    Updated Dec 5, 2019
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 04 [Dataset]. https://hub-cookcountyil.opendata.arcgis.com/datasets/contours-2017-1ft-area-04
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 04. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  5. a

    Contours 2017 1ft Area 19

    • hub-cookcountyil.opendata.arcgis.com
    • arc-gis-hub-home-arcgishub.hub.arcgis.com
    Updated Dec 5, 2019
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 19 [Dataset]. https://hub-cookcountyil.opendata.arcgis.com/datasets/contours-2017-1ft-area-19
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 19. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  6. a

    Contours 2017 1ft Area 31

    • hub-cookcountyil.opendata.arcgis.com
    Updated Dec 5, 2019
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 31 [Dataset]. https://hub-cookcountyil.opendata.arcgis.com/datasets/contours-2017-1ft-area-31
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 31. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  7. a

    Contours 2017 1ft Area 07

    • hub-cookcountyil.opendata.arcgis.com
    Updated Dec 5, 2019
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2019). Contours 2017 1ft Area 07 [Dataset]. https://hub-cookcountyil.opendata.arcgis.com/datasets/contours-2017-1ft-area-07
    Explore at:
    Dataset updated
    Dec 5, 2019
    Dataset authored and provided by
    Cook County Government
    License

    MIT Licensehttps://opensource.org/licenses/MIT
    License information was derived automatically

    Area covered
    Description

    2017 Cook County 1 ft. elevation contours for PLSS Township Area 07. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  8. a

    Contours 2017 1ft

    • hub.arcgis.com
    Updated Jun 22, 2021
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Cook County Government (2021). Contours 2017 1ft [Dataset]. https://hub.arcgis.com/documents/9b57cb59ea414eb2b01040d033365dfb
    Explore at:
    Dataset updated
    Jun 22, 2021
    Dataset authored and provided by
    Cook County Government
    Description

    2017 Cook County 1 ft. elevation contours in a Zipped File Geodatabase. (Clicking on link will download .zip file.) The Cook County, Illinois one foot contours were derived from a 2017 LiDAR acquisition. Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

  9. Not seeing a result you expected?
    Learn how you can add new datasets to our index.

Share
FacebookFacebook
TwitterTwitter
Email
Click to copy link
Link copied
Close
Cite
Cook County Government (2019). Contours 2017 1ft Area 21 [Dataset]. https://hub.arcgis.com/maps/cookcountyil::contours-2017-1ft-area-21

Contours 2017 1ft Area 21

Explore at:
Dataset updated
Dec 5, 2019
Dataset authored and provided by
Cook County Government
License

MIT Licensehttps://opensource.org/licenses/MIT
License information was derived automatically

Area covered
Description

2017 Cook County 1 ft. elevation contours for PLSS Township Area 21. Data is derived from 2017 lidar. If you plan on downloading this dataset it is recommended to use the File Geodatabase option. The shapefile format may not work for larger datasets.Details about creating the one foot contours:The contours were processed by the Cook County GIS Department in order to add contour classifications as Index Contours (every 5 feet), Intermediate Contours (every 1 foot), Index Depression Contours, and Intermediate Depression Contours. To create the classification Cook County GIS used the Identify Contour tool in ArcPro. The input was the contour feature and the 2017 DEM that was delivered along with the LiDAR data. Details about the LiDAR Acquisition:IL 4 County QL1 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a derived nominal pulse spacing (NPS) of 1 point every 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), State Plane, U.S Survey Feet and vertical datum of NAVD88 (GEOID12B), U.S. Survey Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 15,414 individual 2500 ft x 2500 ft tiles, as tiled Reflectance Imagery, and as tiled bare earth DEMs; all tiled to the same 2500 ft x 2500 ft schema.Ground Conditions: Lidar was collected April-May 2017, 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, Ayers established a total of 66 ground control points that were used to calibrate the lidar to known ground locations established throughout the WI Kenosha-Racine Counties and IL 4 County QL1 project area. An additional 195 independent accuracy checkpoints, 116 in Bare Earth and Urban landcovers (116 NVA points), 79 in Tall Grass and Brushland/Low Trees categories (79 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the dataDetails about the DEM: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 Reflectance 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 2 foot cell size. These raw lidar point cloud data were used to create classified lidar LAS files, Reflectance Images, 3D breaklines, 1 foot contours, and hydro-flattened DEMs as necessary.

Search
Clear search
Close search
Google apps
Main menu