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Short Citation:
OCM Partners, 2023: Sonoma County Hydro-flattened 2013 Bare Earth Ground Surface Model, https://www.fisheries.noaa.gov/inport/item/56824.

Item Identification

Title: Sonoma County Hydro-flattened 2013 Bare Earth Ground Surface Model
Short Name: SonomaCty_BareEarth_Hydro_m8783.xml
Status: Completed
Publication Date: 2019-07-08
Abstract:

A bare earth digital elevation model (DEM) represents the earth's surface with all vegetation and human-made structures removed. The bare earth DEMs were derived from LiDAR data using triangulated irregular network (TIN) processing of the ground point returns. Hydro-flattened Bare Earth DEMs represent water bodies in a cartographically and aesthetically pleasing manner, and are not intended to accurately map water surface elevations. In a Hydro-flattened DEM, water surfaces are flat and level for lakes with a greater area than two acres, and gradated for rivers or other long impoundments (e.g., reservoirs) that are wider than 100 feet, and tidal areas. Any existing island larger than one acre was be delineated. Water surface edge elevations were at or below the immediately surrounding terrain. Each image corresponds to a 37,800-square-foot tile. Each pixel is 3 feet and represents an average elevation for that area. The specified coordinate system for this dataset is California State Plane Zone II (FIPS 0402), NAD83 (2011), with units in US Survey Feet for horizontal, and vertical units are NAVD88 (12A) US Survey Feet. The dataset encompasses all of Sonoma County and parts of Mendocino County. WSI collected the LiDAR and created this data set for the Sonoma County Vegetation Mapping and LiDAR Program.

Purpose:

The University of Maryland (under grant NNX13AP69G from NASA’s Carbon Monitoring System, Dr. Ralph Dubayah and Dr. George Hurtt, PIs) contracted LiDAR and orthophoto data collection for all of Sonoma County in late 2013 to support countywide forest carbon mapping. The Sonoma County Vegetation Mapping and LiDAR Program (http://sonomavegmap.org) funded a suite of LiDAR derived products and additional LiDAR collection in two areas in Mendocino County - the Soda Spring Creek-Dry Creek Watershed and Lake Mendocino. This fine scale data will help provide an accurate, up-to-date inventory of the county’s landscape features, ecological communities and habitats.

Project funders include: NASA, the University of Maryland, the Sonoma County Agricultural Preservation and Open Space District, the Sonoma County Water Agency, the California Department of Fish and Wildlife, the United States Geological Survey, the Sonoma County Information Systems Department, the Sonoma County Transportation and Public Works Department, the Nature Conservancy, and the City of Petaluma.

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > SEA FLOOR

Instrument Keywords

Thesaurus Keyword
UNCONTROLLED
Global Change Master Directory (GCMD) Instrument Keywords Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Lidar/Laser Sounders > LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
AIRCRAFT
Global Change Master Directory (GCMD) Platform Keywords
DEM > Digital Elevation Model

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: None Planned
Data Presentation Form: raster digital data
Entity Attribute Detail Citation:

Sonoma County Vegetation Mapping and LiDAR Program

Distribution Liability:

Data were provided by the University of Maryland and the Sonoma County Vegetation Mapping and LiDAR Program (http://sonomavegmap.org) under grant NNX13AP69G from NASA’s Carbon Monitoring System (Dr. Ralph Dubayah, PI). This data is available for unrestricted public use. However, users should acknowledge the source of the data in any reports, publications, or presentations where the data is used.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners

Data Set Credit: Sonoma County Vegetation Mapping and LiDAR Consortium, NASA, University of Maryland, Watershed Sciences, Inc., Tukman Geospatial LLC, Sonoma County Vegetation Mapping and LiDAR Program

Support Roles

Data Steward

CC ID: 859774
Date Effective From: 2019
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 859773
Date Effective From: 2019
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Metadata Contact

CC ID: 859775
Date Effective From: 2019
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 859776
Date Effective From: 2019
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1152903
W° Bound: -123.238581
E° Bound: -122.390681
N° Bound: 38.511668
S° Bound: 38.298129

Extent Group 1 / Time Frame 1

CC ID: 1152902
Time Frame Type: Range
Start: 2013-09-28
End: 2013-11-26

Spatial Information

Spatial Resolution

Horizontal Distance: 3.0 Foot

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1152900

Coordinate Reference System

CRS Type: Vertical
EPSG Code: EPSG:6360
EPSG Name: NAVD88 height (ftUS)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for custom downloads

Data Access Constraints:

None

Data Use Constraints:

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

Distribution Information

Distribution 1

CC ID: 859780
Start Date: 2019-07-08
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8783
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

File Type: Zip
Compression: Zip

Distribution 2

CC ID: 859781
Start Date: 2019-07-08
End Date: Present
Download URL: https://coast.noaa.gov/htdata/raster2/elevation/Sonoma_CA_DEM_2013_8783
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type: GeoTIFF

URLs

URL 1

CC ID: 859770
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 2

CC ID: 859771
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12a/4703/supplemental/2013_Sonoma_County_Lidar.kmz
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 3

CC ID: 859772
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12a/4703/supplemental/Final_Data_Report_-_All_LiDAR_Deliveries.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

Data Quality

Horizontal Positional Accuracy:

Relative Accuracy measures the divergence between points from different flightlines. Relative Accuracy median is 0.05 meters (0.17 feet) out of 106,255,665,985 laser points over 4,133 flightlines. For more information regarding the internal consistency between ground-classified points from different overlapping flightlines please see LiDAR data report.

Vertical Positional Accuracy:

The Fundamental Vertical Accuracy (FVA) of the data set was compiled to meet 0.03 meters (0.09 feet). Accuracy was assessed using 9,685 survey ground check points. These ground check points are distributed through out the project study area. See LiDAR data report.

Qualitative value:0.05 meters RMSEz at 95 percent Confidence Interval., Test that produced the value: The FVA was tested using 851 independent ground control points (GCPs) located in open terrain. The GCPs were distributed throughout the project area. Elevations from the unclassified LiDAR surface were measured for the x,y location of each check point. Elevations interpolated from the LiDAR surface were then compared to the elevation values of the surveyed control. The Root-Mean-Square (RMSE) was computed to be 0.03 m (0.09 ft.). Using withheld ground checkpoints, vertical accuracy has been tested to meet 0.05 m (0.17 ft.) FVA at 95 Percent confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Completeness Report:

LiDAR has been collected and processed for all areas within the project study Area. In some areas of heavy vegetation and forest cover, there may be relatively few ground points in the LiDAR data. Some elevation units have been interpolated across areas in the ground model where there are no elevation data (e.g., over water, over dense vegetation). TINing the points produces large triangles and hence the elevations may be less accurate within such areas. Some elevation units have been interpolated across areas in the ground model where there are no elevation data (e.g., over water, over dense vegetation).

Conceptual Consistency:

LiDAR flight lines have been examined to ensure that there was at least 60% sidelap, there are no gaps between flightlines, and overlapping flightlines have consistent elevation values. Shaded relief images have been visually inspected for data errors such as pits, border artifacts, gaps, and shifting. The data were examined at a 1:3000 scale.

Lineage

Sources

Hydro Breaklines

CC ID: 1152894
Publish Date: 2014-02-19
Extent Type: Range
Extent Start Date/Time: 2013-09-28
Extent End Date/Time: 2013-11-26
Source Contribution:

Breaklines were created by WSI for the Hydro-flattened Bare Earth raster dataset.

Hydro-flattened DEMs

CC ID: 1152895
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Watershed Sciences Inc

Process Steps

Process Step 1

CC ID: 1152896
Description:

Acquisition.

LiDAR data acquisition was started September 28, 2013 and was completed on November 26, 2013. The survey is utilizing a Leica ALS50 or ALS70 laser system mounted in a Piper Navajo PA-31-325 or Cessna Caravan 208B. Near nadir scan angles were used to increase penetration of vegetation to ground surfaces. Ground level GPS and aircraft IMU were collected during the flight.

Process Date/Time: 2014-02-19 00:00:00

Process Step 2

CC ID: 1152897
Description:

Hydro-Flattening.

The bare-earth DEMs were created by triangulating all ground classified points and inserting 3-D breaklines by utilizing Terra-Solid’s TerraScan and TerraModeler software. Any ground points within one meter of the breaklines were reclassified to “ignored-ground” (ASPRS code: 10) before triangulation. The highest-hit DEMs were generated from “ground” and “default” classified points. In instances where “water” classified points had the highest elevation value, the water surface elevation from the bare-earth raster were used.

Process Date/Time: 2014-02-19 00:00:00

Process Step 3

CC ID: 1152898
Description:

LiDAR Data Processing.

Flight lines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. Laser point return coordinates were computed using ALS Post Processor software and IPAS Pro GPS/INS software, based on independent data from the LiDAR system, IMU, and aircraft. The raw LiDAR file was assembled into flight lines per return with each point having an associated x, y, and z coordinate. Visual inspection of swath to swath laser point consistencies within the study area were used to perform manual refinements of system alignment. Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based upon randomly selected swath to swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll and yaw offset parameters optimize internal consistency. Noise (e.g., pits and birds) was filtered using ALS post-processing software, based on known elevation ranges and included the removal of any cycle slips. Using TerraScan and MicroStation, ground classifications utilized custom settings appropriate to the study area. The corrected and filtered return points were compared to the RTK ground survey points collected to verify the vertical and horizontal accuracies. Points were output as laser points, TINed and GRIDed surfaces.

Process Date/Time: 2014-02-19 00:00:00

Process Step 4

CC ID: 1152899
Description:

NOAA Office for Coastal Management received the DEMs in imagine format with img and ige files. Data were converted to GeoTiff format with deflate compression using gdal_translate. Vertical georeferencing was also added.

Process Date/Time: 2019-07-08 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address: coastal.info@noaa.gov
Source: Hydro-flattened DEMs

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference Sonoma County, CA, 2013 Lidar

Lidar point cloud used for this data set.

Catalog Details

Catalog Item ID: 56824
GUID: gov.noaa.nmfs.inport:56824
Metadata Record Created By: Kirk Waters
Metadata Record Created: 2019-07-08 13:04+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16