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Short Citation:
OCM Partners, 2023: 2015 St. Marys River Topobathymetric Lidar DEM,

Item Identification

Title: 2015 St. Marys River Topobathymetric Lidar DEM
Short Name: st_marys_2015_usace_m6232_metadata
Status: Completed
Publication Date: 2017

In September 2015, Quantum Spatial (QSI) was contracted by the United States Army Corps of Engineers (USACE) to collect topobathymetric Light Detection and Ranging (lidar) data in the fall of 2015 for selected areas of the St. Marys River in Michigan and Ontario, Canada. Traditional near-infrared (NIR) lidar was fully integrated with green wavelength return data (bathymetric) lidar in order to provide seamless and complete project mapping. Data were collected to aid USACE in assessing the topographic and geophysical properties (channel morphology and topobathymetric surface) of the study area.

Data described here are the 1.0 meter DEM rasters for an integrated topobathymetric model. The lidar point cloud is also available through the NOAA Digital Coast. The data received by NOAA from USACE did not include a compliant metadata record. This record was generated from information in the lidar report.


Classified LAS files were collected to aid USACE in assessing the topographic and geophysical properties (channel morphology and topobathymetric surface) of the study area.



Supplemental Information:

CONTRACTOR: Quantum Spatial, Inc

Ground Control Points were acquired and calibrated by Quantum Spatial, Inc.

All Lidar data acquisition, calibration, and follow-on processing were completed by the prime contractor.

A project report with more detail is available at https://


Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
Global Change Master Directory (GCMD) Science Keywords
ISO 19115 Topic Category
None DEM
None Hydrology

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Data Presentation Form: Lidar DEM
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of USACE, Quantum Spatial, the NOAA Office for Coastal Management, or their partners.

Data Set Credit: Quantum Spatial, Inc. flew the lidar and processed the data.

Support Roles

Data Steward

CC ID: 663901
Date Effective From: 2017
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 663903
Date Effective From: 2017
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 663904
Date Effective From: 2017
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 663902
Date Effective From: 2017
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Time Frame 1

CC ID: 1150280
Time Frame Type: Range
Start: 2015-10-09
End: 2015-11-29

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL:

The lidar point cloud source data can be obtained on-line at:


Data Access Constraints:

No restrictions apply to these data.

Data Use Constraints:

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 it's limitations. Acknowledgement of the USACE Detroit District would be appreciated for products derived from these data.

Distribution Information

Distribution 1

CC ID: 721032
Download URL:
File Name: Customized Download

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Distribution 2

CC ID: 721033
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 721035
URL Type:
Online Resource


CC ID: 721036
URL Type:
Online Resource


CC ID: 721037
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the lidar footprint for the 2015 USACE LRE St Marys River topobathy lidar project in Michigan

Activity Log

Activity Log 1

CC ID: 663923
Activity Date/Time: 2017-01-31

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 663922
Activity Date/Time: 2017-11-14

Converted from FGDC Content Standard for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718620
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 721034
Activity Date/Time: 2018-02-13

Partial upload to move data access links to Distribution Info.

Data Quality

Vertical Positional Accuracy:

Topographic and Bathymetric accuracies were assessed separately. The topographic assessment used 164 points and the bathymetric assessment used 334 points. Individually, these had Fundamental Vertical Accuracy (1.96 * RMSE) values of 0.045 and 0.094 meters respectively. The aggregate accuracy is reported as the accuracy here.; Quantitative Value: 0.081 meters, Test that produced the value: Absolute accuracy was assessed using Fundamental Vertical Accuracy (FVA) reporting designed to meet guidelines presented in the FGDC National Standard for Spatial Data Accuracy3. FVA compares known ground check point data collected on open, bare earth surfaces with level slope (less than 20 degrees) to the triangulated surface generated by the lidar points. FVA 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). A combined topographic and bathymetric accuracy is reported here.

Completeness Report:

Datasets contain complete coverage of tiles.

No points have been removed or excluded.

A visual qualitative assessment was performed to ensure data completeness.

There are no void areas or missing data. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Conceptual Consistency:

Classified LAS files were tested by Quantum Spatial for both vertical and horizontal accuracy. All data is seamless from one tile to the next, no gaps or no data areas.



Lidar RAW Data for St. Marys River 2015

CC ID: 1150276
Publish Date: 2015-01-01
Extent Type: Range
Extent Start Date/Time: 2015-10-09
Extent End Date/Time: 2015-11-29
Source Contribution:

This data source was used to populate the lidar point cloud data. | Source Geospatial Form: lidar data | Type of Source Media: online

Process Steps

Process Step 1

CC ID: 1150277

The Riegl VQ-820-G was selected as the hydrographic airborne laser scanner for the St. Marys River project based on fulfillment of several considerations deemed necessary for effective mapping of the project site. A high repetition pulse rate, high scanning speed, small laser footprint, and wide field of view allow for seamless collection of high resolution data of both topographic and bathymetric surfaces. A short laser pulse length allows for discrimination of underwater surface expression in shallow water, critical to shallow and dynamic environments. The Riegl system has demonstrated hydrographic depth ranging capability up to 1 Secchi depth on bright reflective surfaces.

The LiDAR survey was accomplished using a Leica ALS50 system dually mounted with a Riegl VQ-820-G topobathymetric sensor in a Cessna Caravan 208B. The Riegl VQ-820-G uses a green wavelength (lambda=532 nm) laser that is capable of collecting high resolution vegetation and topography data, as well as penetrating the water surface with minimal spectral absorption by water. The recorded waveform enables range measurements for all discernible targets for a given pulse. The typical number of returns digitized from a single pulse range from 1 to 7 for the St. Marys River project area. The Leica ALS50 laser system records up to four range measurements (returns) per pulse. It is not uncommon for some types of surfaces (e.g., dense vegetation or water) to return fewer pulses to the LiDAR sensor than the laser originally emitted. The discrepancy between first return and overall delivered density will vary depending on terrain, land cover, and the prevalence of water bodies. All discernible laser returns were processed for the output dataset.

Processing workflow was as follows:

Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey.

Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las (ASPRS v. 1.2) format. Convert data to orthometric elevations by applying a geoid12b correction.

Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines.

Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration.

Apply refraction correction to all subsurface returns.

Classify resulting data to ground and other client designated ASPRS classifications . Assess statistical absolute accuracy via direct comparisons of ground classified points to ground control survey data.

Generate bare earth models as triangulated surfaces. Generate highest hit models as a surface expression of all classified points. Export all surface models as ESRI GRIDs at a 1 meter pixel resolution.

Process Date/Time: 2016-01-01 00:00:00

Process Step 2

CC ID: 1150278

Data were received by the NOAA Office for Coastal Management from the USACE Detroit District in the form described above. It was ingested into the Digital Coast Data Access Viewer system for distribution by converting the ESRI GRID raster format to GeoTIFF using gdal_translate. This was done to provide an open format.

Process Date/Time: 2017-01-01 00:00:00

Catalog Details

Catalog Item ID: 49464
GUID: gov.noaa.nmfs.inport:49464
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:13+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