Search Help Show/Hide Menu
Summary
Item Identification
Keywords
Physical Location
Data Set Info
Support Roles
Extents
Spatial Info
Access Info
Distribution Info
URLs
Data Quality
Data Management
Lineage
Catalog Details

Summary

Browse graphic

Short Citation
OCM Partners, 2024: 2017 NYC Topobathy Lidar Hydroenforced DEM: New York City, https://www.fisheries.noaa.gov/inport/item/64734.
Full Citation Examples

Abstract

Product: The bare earth digital elevation model (DEM) represents the earth's surface with all vegetation and anthropogenic features removed. It is derived from Green and NIR LiDAR data using TIN processing of the ground and bathymetric bottom point returns. Additionally, hydro-enforcement breaklines were created at all artificial obstructions to flow found in the ground model (i.e. culverts) to break the obstruction and allow flow to continue; these features have been 'burned-in' to this version of the DEM. A separate version is available without these hydro-enforcements through the Digital Coast, while a third DEM is available through the New York State GIS repository that is hydroconditioned - having had 'sinks' filled, in addition to culverts 'burned'.

Geographic Extent: New York, Bronx, Kings, Queens, and Richmond Counties in New York plus an additional 100 m buffer.

Dataset Description: In May 2017, Quantum Spatial (QSI) was contracted by Applied Geographics (AppGeo) to collect topographic and topobathymetric Light Detection and Ranging (LiDAR) data for the City of New York (NYC). QSI collected and processed traditional (near infrared wavelength, Leica ALS80 sensor) LiDAR over the topographic AOI, and spliced together NIR and bathymetric LiDAR (green wavelength, Riegl VQ-880-G sensor) for the topobathymetric AOI.

Ground Conditions: Topographic LiDAR was collected in May 2017 with approximately 50% leaf-off conditions. Bathymetric data was collected in July 2017 during low tide time windows. Ground control data were used to geospatially correct the LiDAR point cloud and used to perform quality assurance checks on the final products. In addition, Continuously Operating Reference Stations (CORS) from the New York State Spatial Reference Network (NYSNet) were used to geospatially correct the aircraft positional coordinate data and as base stations for GSP collection. All ground survey work to support the topobathymetric LiDAR acquisition was conducted during the NIR LiDAR collection window. Land cover class check points were also collected throughout the study area to evaluate vertical accuracy.

Distribution Information

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

  • GeoTIFF

    Bulk download of data files in the original coordinate system.

Access Constraints:

None

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.

Controlled Theme Keywords

COASTAL BATHYMETRY, COASTAL ELEVATION, elevation, TERRAIN ELEVATION

Child Items

No Child Items for this record.

Contact Information

Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov

Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov

Extents

Geographic Area 1

-74.257499° W, -73.69803° E, 40.916459° N, 40.491252° S

Time Frame 1
2017-05-03 - 2017-07-26

Item Identification

Title: 2017 NYC Topobathy Lidar Hydroenforced DEM: New York City
Status: Completed
Publication Date: 2018-11-09
Abstract:

Product: The bare earth digital elevation model (DEM) represents the earth's surface with all vegetation and anthropogenic features removed. It is derived from Green and NIR LiDAR data using TIN processing of the ground and bathymetric bottom point returns. Additionally, hydro-enforcement breaklines were created at all artificial obstructions to flow found in the ground model (i.e. culverts) to break the obstruction and allow flow to continue; these features have been 'burned-in' to this version of the DEM. A separate version is available without these hydro-enforcements through the Digital Coast, while a third DEM is available through the New York State GIS repository that is hydroconditioned - having had 'sinks' filled, in addition to culverts 'burned'.

Geographic Extent: New York, Bronx, Kings, Queens, and Richmond Counties in New York plus an additional 100 m buffer.

Dataset Description: In May 2017, Quantum Spatial (QSI) was contracted by Applied Geographics (AppGeo) to collect topographic and topobathymetric Light Detection and Ranging (LiDAR) data for the City of New York (NYC). QSI collected and processed traditional (near infrared wavelength, Leica ALS80 sensor) LiDAR over the topographic AOI, and spliced together NIR and bathymetric LiDAR (green wavelength, Riegl VQ-880-G sensor) for the topobathymetric AOI.

Ground Conditions: Topographic LiDAR was collected in May 2017 with approximately 50% leaf-off conditions. Bathymetric data was collected in July 2017 during low tide time windows. Ground control data were used to geospatially correct the LiDAR point cloud and used to perform quality assurance checks on the final products. In addition, Continuously Operating Reference Stations (CORS) from the New York State Spatial Reference Network (NYSNet) were used to geospatially correct the aircraft positional coordinate data and as base stations for GSP collection. All ground survey work to support the topobathymetric LiDAR acquisition was conducted during the NIR LiDAR collection window. Land cover class check points were also collected throughout the study area to evaluate vertical accuracy.

Purpose:

Data were collected to help support the City’s many agencies in planning and analysis related to their key initiatives. LiDAR derived DEMs will be crucial for long-term land use planning and assessing the impacts of sea level rise.

Supplemental Information:

As part of a federal Disaster Recovery Community Development Block Grant ("CDBG-DR"), the New York City (NYC) Mayor’s Office of Recovery and Resiliency (ORR), Department of Information Technology and Telecommunications (DoITT) and Department of Parks and Recreation (Parks) contracted with AppGeo for the acquisition of Light Detection and Ranging (LiDAR) data, developing LiDAR-derived products, and generating high-resolution land cover. Quantum Spatial Inc. was subcontracted for acquisition and processing of the LiDAR data.

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 > BATHYMETRY > COASTAL BATHYMETRY
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
Global Change Master Directory (GCMD) Location Keywords Continent > North America > United States Of America > New York State >

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
UNCONTROLLED
Global Change Master Directory (GCMD) Location Keywords Continent > North America > United States Of America > U.S. Coastline

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane

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: As Needed
Data Presentation Form: Model (digital)
Distribution Liability:

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: New York City Department of Information Technology and Telecommunications

Support Roles

Data Steward

CC ID: 1068016
Date Effective From: 2021
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: 1068015
Date Effective From: 2021
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: 1068017
Date Effective From: 2021
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: 1068018
Date Effective From: 2021
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: 1295032
W° Bound: -74.257499
E° Bound: -73.69803
N° Bound: 40.916459
S° Bound: 40.491252

Extent Group 1 / Time Frame 1

CC ID: 1295031
Time Frame Type: Range
Start: 2017-05-03
End: 2017-07-26

Spatial Information

Spatial Representation

Representations Used

Grid: No
Vector: No
Text / Table: No
TIN: Yes
Stereo Model: No
Video: No

Reference Systems

Reference System 1

CC ID: 1295028

Coordinate Reference System

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

Reference System 2

CC ID: 1295029

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6539
EPSG Name: NAD83(2011) / New York Long Island (ftUS)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk or 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: 1068019
Start Date: 2021-06-02
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9310/details/9310
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present)
File Name: Customized Download
Description:

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

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 1068020
Start Date: 2021-06-02
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/NYC_topobathy_hydroEnforced_DEM_2017_9310/
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type (Deprecated): GeoTIFF (.tif)
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 1068021
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: 1068022
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9306/supplemental/extent_nyc_topobathy_2017_m9306.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: 1068023
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9306/supplemental/New_York_City_2017_Topobathymetric_LiDAR_Report_FINAL.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

Data Quality

Vertical Positional Accuracy:

Absolute accuracy was assessed using Non-vegetated Vertical Accuracy (NVA) reporting designed to meet guidelines presented in the FGDC National Standard for Spatial Data Accuracy. NVA compares known ground quality assurance point data collected on open, bare earth surfaces with level slope (<20 degrees) to the triangulated surface generated by the LiDAR points. NVA is a measure of the accuracy of LiDAR point data in open areas where the LiDAR system has a high probability of measuring the ground surface and is evaluated at the 95% confidence interval (1.96 * RMSE).

The mean and standard deviation (sigma) of divergence of the ground surface model from ground check point coordinates are also considered during accuracy assessment. These statistics assume the error for x, y and z is normally distributed, and therefore the skew and kurtosis of distributions are also considered when evaluating error statistics. For the New York City Topographic and Topobathymetric LiDAR survey, 151 ground check points were withheld from the calibration and post-processing of the LiDAR point cloud, resulting in a non-vegetated vertical accuracy of 0.242 feet (0.074 meters), with 95% confidence. RMSE = 0.038 meters.

Bathymetric (submerged or along the water’s edge) check points were also collected in order to assess the submerged surface vertical accuracy. Assessment of 115 bathymetric check points resulted in a vertical accuracy of 0.208 feet (0.064 meters), evaluated at the 95th percentile.

QSI also assessed absolute accuracy using 2,416 ground control points. Although these points were used in the calibration and post-processing of the LiDAR point cloud, they still provide a good indication of the overall accuracy of the LiDAR dataset, and therefore have been provided in the Project Report, linked elsewhere in the metadata record.

Completeness Report:

The classified point cloud was inspected and passed accuracy specifications.

Conceptual Consistency:

Data covers the entire area specified for this project.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Actual or Planned Long-Term Data Archive Location: NCEI-CO
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

Data is backed up to tape and to cloud storage.

Lineage

Lineage Statement:

Data were collected and processed by Quantum Spatial, Inc. for the New York City Department of Information Technology and Telecommunications. The data were retrieved from the New York State GIS FTP website [ address: ftp://ftp.gis.ny.gov/elevation/LIDAR/NYC_TopoBathymetric2017/ ] by the NOAA Office for Coastal Management (OCM), where the data were processed to make it available for custom download from the Data Access Viewer (DAV) and bulk download from https

Sources

Lidar Data

CC ID: 1295025
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Quantum Spatial, Inc.
Citation URL: http://quantumspatial.com/
Citation URL Name: Quantum Spatial

Process Steps

Process Step 1

CC ID: 1295026
Description:

The following outlines the processing of the point cloud data:

1. Flightlines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points.

2. Laser point return coordinates were computed using Waypoint Inertial Explorer and Leica Cloudpro software based on independent data from the LiDAR system, IMU, and aircraft.

3. The raw LiDAR file was assembled into flight lines per return with each point having an associated x, y, and z coordinate.

4. Visual inspection of swath to swath laser point consistencies within the study area were used to perform manual refinements of system alignment.

5. 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.

6. Noise (e.g., pits and birds) was filtered using post-processing software, based on known elevation ranges and included the removal of any cycle slips.

7. Using TerraScan and Microstation, ground classifications utilized custom settings appropriate to the study area.

8. The corrected and filtered return points were compared to the ground survey points collected to verify the vertical accuracy.

9. TIN processing of the ground point returns with water's edge breaklines enforced was used to create this hydro-flattened bare earth DEM.

Process Date/Time: 2018-01-01 00:00:00
Source: Lidar Data

Process Step 2

CC ID: 1295027
Description:

The NOAA Office for Coastal Management (OCM) retrieved 31 DEM files in geoTIFF format from the New York State GIS website. The data were in NAD83 (2011) State Plane New York Long Island (FIPS 3104) in US Feet, and NAVD88 (Geoid12B) elevations in feet. The bare earth raster files were at a 1 foot grid spacing.

OCM assigned the appropriate EPSG codes (Horiz - 6539, Vert - 6360) and copied the raster files to https for Digital Coast storage and provisioning purposes.

Process Date/Time: 2021-06-02 00:00:00
Process Contact: Office for Coastal Management (OCM)

Catalog Details

Catalog Item ID: 64734
GUID: gov.noaa.nmfs.inport:64734
Metadata Record Created By: Blake Waring
Metadata Record Created: 2021-06-04 17:04+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-10 19:16+0000
Metadata Record Published: 2024-01-10
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