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Short Citation:
OCM Partners, 2023: 2017 MDWS Lidar: Calvert County, MD,

Item Identification

Title: 2017 MDWS Lidar: Calvert County, MD
Short Name: MD_Calvert 2017 m9237
Status: Completed
Publication Date: 2018-02-01

Product: Calibrated LiDAR version 1.4 .las tiles, classified to bare earth for subsequent derivatives.

Geographic Extent: Calvert County, Maryland, covering approximately 221 square miles.

Dataset Description: Calvert County, Maryland 2017 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35m. 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), MD NAD83 G12B, feet and vertical datum of Geoid12B, US Feet. Lidar data was delivered as flightline-extent unclassified LAS swaths, as processed Classified LAS 1.4 files, formatted to 1139 individual 4000ft x 6000ft tiles, as tiled bare earth DEMs; all tiled to the same 4000ft x 6000ft MAryland Ortho Tile schema.

Ground Conditions: Lidar was collected in early 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, State of Maryland, Axis GeoSpatial LLC established a total of 16 ground control points that were used to calibrate the lidar to known ground locations established throughout the Calvert County, Maryland project area. An Additional 40 QA Checkpoints, 25 NVA and 15 VVA were used to calculate absolute vertical accuracies to verfiy data met USGS specifications.


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 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 Feet cell size. These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs as necessary.

Supplemental Information:


The following are the USGS lidar fields in JSON:


"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Lidar Specification v1.2",

"ldrsens" : "Riegl Q1560 LiDAR System (Axis GeoSpatial LLC)",

"ldrmaxnr" : "7",

"ldrnps" : ".33",

"ldrdens" : "9",

"ldranps" : ".35",

"ldradens" : "8.0",

"ldrfltht" : "719",

"ldrfltsp" : "133",

"ldrscana" : "58.52",

"ldrscanr" : "84.3",

"ldrpulsr" : "766",

"ldrpulsd" : "5",

"ldrpulsw" : ".60",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "2644",

"ldrswato" : "20",

"ldrcrs" : "North American Datum of 1983 (2011) Maryland State Plane Coordinate System US Feet",

"ldrgeoid" : "Geodetic Reference System 80"


"ldraccur" : {

"ldrchacc" : "0.12288m",

"rawnva" : "0.03m",

"rawnvan" : "25"


"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.",

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit.",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"


"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare Earth Ground"


"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"


"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"


"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground"


"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"


"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"




Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
Global Change Master Directory (GCMD) Science Keywords
Global Change Master Directory (GCMD) Science Keywords
ISO 19115 Topic Category

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
Global Change Master Directory (GCMD) Location Keywords

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: None Planned
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: Axis Geospatial, LLC; State of Maryland

Support Roles

Data Steward

CC ID: 1038966
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:
Phone: (843) 740-1202


CC ID: 1038965
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:
Phone: (843) 740-1202

Metadata Contact

CC ID: 1038967
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:
Phone: (843) 740-1202

Point of Contact

CC ID: 1038968
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:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1145569
W° Bound: -76.711902
E° Bound: -76.359246
N° Bound: 38.778376
S° Bound: 38.31019

Extent Group 1 / Time Frame 1

CC ID: 1145568
Time Frame Type: Range
Start: 2017-01-25
End: 2017-02-01

Spatial Information

Spatial Representation

Representations Used

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

Vector Representation 1

CC ID: 1038961
Point Object Present?: Yes
Point Object Count: 16779766211

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk or custom downloads

Data Access Constraints:


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: 1038972
Start Date: 2021-02-10
End Date: Present
Download URL:
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present)
File Name: Customized Download

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. Change to an orthometric vertical datum is one of the many options.

File Type: Zip
Compression: Zip

Distribution 2

CC ID: 1038973
Start Date: 2021-02-10
End Date: Present
Download URL:
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - Present)
File Name: Bulk Download

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

File Type: LAZ
Compression: Zip



CC ID: 1038963
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML

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.


CC ID: 1038964
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML

This graphic displays the footprint for this lidar data set.

Data Quality

Vertical Positional Accuracy:

After contacting Axis Geospatial in May 2021, determined that the vertical accuracy is 3.7 cm RMSE based on 44 checkpoints.

Completeness Report:

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. Points with extreme elevations (negative values, or positive values well above the expected maximum) are present in this dataset. These points are classified as low or high noise in classified point cloud tiles.

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.



Classified point cloud

CC ID: 1145564
Contact Role Type: Publisher
Contact Type: Organization
Contact Name: Maryland iMAP
Citation URL:
Citation URL Name: Maryland iMAP lidar download page
Source Contribution:

Source of original point cloud

Process Steps

Process Step 1

CC ID: 1145565

LAS Point Classification: The point classification is performed as described below. The bare earth surface is manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through digitization. All ground (ASPRS Class 2) lidar data inside of Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 1 Foot was also used around each hydro-flattened feature to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 10). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by LasTools to appropriately bit flag overlapping flight line data per USGS specifications. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. LP360 was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Axis GeoSpatial LLC proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.

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

Process Step 2

CC ID: 1145566

Data were downloaded from the Maryland iMAP and converted to ingest into the Digital Coast Data Access Viewer. Changes made were:

1) Convert from NAD83(2011) Maryland state plane feet to NAD83(2011) geographic coordinates.

2) Convert from NAVD88(Geoid12b) in feet to NAD83(2011) ellipsoid heights in meters.

3) Names were changed to include the YYYYMMDD of the first point in a file as the beginning of the file name.

Process Date/Time: 2021-02-10 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address:
Source: Classified point cloud

Catalog Details

Catalog Item ID: 64283
GUID: gov.noaa.nmfs.inport:64283
Metadata Record Created By: Kirk Waters
Metadata Record Created: 2021-02-10 15:22+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-08-15 17:09+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