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Short Citation:
OCM Partners, 2023: 2002 Maryland Department of Natural Resources LiDAR: Worcester County,

Item Identification

Title: 2002 Maryland Department of Natural Resources LiDAR: Worcester County
Short Name: md2002_m15_metadata
Status: Completed
Publication Date: 2006-10-18

Light Detection and Ranging (LiDAR) is a method of locating objects on the ground using aerial-borne equipment.

It is similar to RADAR or SONAR in that the two-way travel time of an energy beam reflected off an object is precisely measured,

but this technology uses laser light instead of radio or sound waves. This technology has proven very useful in remote sensing

of the earth. It can be used for determining elevations of both the earth's surface and items (natural and man-made) on the surface.

Analysis of LiDAR data is used in detailed modeling of the earth's surface for drainage and floodplain studies, determining how a

new structure will affect views from various locations, shoreline erosion studies, and other reasons. This data set contains only

the bare earth mass points. Bare earth points represent ground features. Features that are above ground, such as buildings, bridges,

tree tops, etc, have been eliminated. Mass points may appear to have "holes" with no elevation values in areas where the surface

could not be determined, such as very dense forests or urban areas.

Original contact information:

Contact Org: NOAA Office for Coastal Management

Phone: 843-740-1202



The LiDAR-derived data were collected by the Maryland Department of Natural Resources in support of shore erosion studies

along the shorelines of the Chesapeake Bay. It also supports the Federal Emergency Management Agency's specifications for mapping

floodplains. These efforts required detailed elevation data and models, such as those available from LiDAR sensing. The data have

also been made available to aid in other projects that require detailed surface, vegetation and/or structure elevations.



Other Citation Details:

1. Airborne 1 (flight firm)

2. Computational Consulting Services, LLC (processing firm)

3. Spatial Systems Associates, Inc. (post-processing firm)

4. Dewberry & Davis (QA/QC firm)

5. Maryland Department of Natural Resources

Supplemental Information:

These data are part of a suite of spatial data products generated using the LIDAR technology. First and

Last returns are generated. From these data, Bare-Earth Mass Points that represent the earths surface are produced. A gridded

Digital Elevation Model (DEM) is produced from the Bare Earth Mass Points. Imagery is also created that represents the intensity

of the LIDAR return; it is a 1-meter resolution product that resembles a panchromatic Digital Orthophoto Quad (DOQ).

The Worcester County, Maryland LiDAR Review-2005 Report may be viewed at:


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None Bald earth
None Bare earth
None DNR
None First return
None Mass points

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
Distribution Liability:

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

Data Set Credit: The 2002 Maryland LIDAR data were collected for the Maryland Department of Natural Resources. Spatial Systems Associates, Inc. was the prime contractor for this project. It partnered with Airborne 1 Corporation, Computational Consulting Services, Inc., NXL Construction Services, Inc and Dewberry LLC. The following organizations participated with DNR and its vendor in funding the collecting and processing of the LIDAR data. They are: City of Salisbury, Salisbury University, University of Maryland, Dorchester County, Talbot County and the National Ocean and Atmospheric Administration's (NOAA) Office for Coastal Management (OCM).

Support Roles

Data Steward

CC ID: 676854
Date Effective From: 2006-10-18
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: 676856
Date Effective From: 2006-10-18
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: 676857
Date Effective From: 2006-10-18
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: 676855
Date Effective From: 2006-10-18
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: 1133658
W° Bound: -75.566159
E° Bound: -75.024282
N° Bound: 38.465226
S° Bound: 37.979965

Extent Group 1 / Time Frame 1

CC ID: 1133657
Time Frame Type: Range
Start: 2002-09-01
End: 2003-01-01

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

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

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. The NOAA and Department of Natural Resources makes no warranty, expressed or implied, as to the

use or appropriateness of Spatial Data, and there are no warranties of merchantability or fitness for a particular purpose or use.

The information contained in Spatial Data is from publicly available sources, but no representation is made as to the accuracy or

completeness of Spatial Data. The Department of Natural Resources shall not be subject to liability for human error, error due to

software conversion, defect, or failure of machines, or any material used in the connection with the machines, including tapes, disks,

CD-ROMs or DVD-ROMs and energy. The Department of Natural Resources shall not be liable for any lost profits, consequential damages,

or claims against the Department of Natural Resources by third parties. The liability of the Department of Natural Resources for

damage regardless of the form of the action shall not exceed any distribution fees that may have been paid in obtaining Spatial Data.

Distribution Information

Distribution 1

CC ID: 741306
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: 741307
Download URL:
File Name: Bulk Download

Simple download of data files.

Activity Log

Activity Log 1

CC ID: 676888
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 676887
Activity Date/Time: 2017-11-14

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

Activity Log 3

CC ID: 718349
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 741308
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality


None available

Horizontal Positional Accuracy:

The horizontal coordinate values were designed to meet NSSDA accuracy for data at

1:2400 scale.

Vertical Positional Accuracy:

The RMSE value of 14.3 cm at the 95% confidence level was determined by an independent

accuracy assessment conducted by Dewberry LLC according to the contract specifications. These specifications followed FEMA

Appendix A guidelines regarding assessing vertical accuracy. For data accurate to within 18.5 cm RMSE, the guidelines

recommended a minimum of 20 independent check points be located in each of 5 different land cover categories: Grass/Ground,

High Grass/Crops, Brush/Low Trees, Forest, and Urban/Pavement. A total of 125 points were used for the assessments. These

points were surveyed by a licensed land surveyor and provided a positional location and elevation with an accuracy that

exceeded the predicted accuracy of the LIDAR data. The entire accuracy reports can be found at

; Quantitative Value: 14.3 meters, Test that produced the value:

The RMSE value is 14.3 cm. See the Vertical Positional Accuracy Report section

for more information.

Completeness Report:

Spatial Systems Associates performed various inspections of the data to ensure: that each file contained the points

located within that tile; that tiles were completely filled; that the point density per tile was within expected ranges, and that

the tiles were correctly named.

Conceptual Consistency:

Computational Consulting Services, the LIDAR processing vendor used proprietary algorithms to remove

features and artifacts in the First and Last Return data that did not reflect true ground elevation. Subsequent quality assurance

testing by Dewberry determined that the data met FEMA and MD DNR specifications for both vertical accuracy and other consistencies

with accepted standards. The QA report can be accessed at <>.



Elevation Data - LiDAR Bare Earth Mass Points

CC ID: 1133649
Publish Date: 2004-03-20
Extent Type: Range
Extent Start Date/Time: 2003-03-01
Extent End Date/Time: 2003-11-30
Source Contribution:

Bare-earth LIDAR x-y-z-i data files | Type of Source Media: Disc

Process Steps

Process Step 1

CC ID: 1133650

LIDAR Data Acquisition. Airborne 1, using an Optec 25 MHz system, flew the project area with the LIDAR sensor.

A portion of the 2003 project area included data acquisition of portions of the LIDAR 2002 project area that had incomplete

coverage. Where overlaps between the two series of data occurred, the newer data was used. No attempt at blending the two datasets

was made to maintain the highest data integrity. In an effort to permit correlation of the point values with tidal gauge stations,

the Airborne 1 was required to fly tidal shoreline areas during the low tide cycle (slack water - low tide - slack water) as

predicted by local tide stations. The LIDAR sensor collected raw data that was referenced in UTM. The specifications called

for data collection during leaf-off conditions, which generally run through early to mid April. However, due to late winter

snow cover, windy flight conditions and other technical obstacles, data acquisitions continued into early June 2003. In addition,

a small area in the north end of the project area was acquired in July. Anticipating the trouble with leaf density, Airborne 1

modified the flight parameters to increase the laser light penetration to the ground. The flight plan on this project included

the following specifications to meet the project requirements: *Single pass density - 1.696 square meters per sample;

*Average area sampling density -1.272 square meters per sample; *Swath width - 996.76 meters; *Flight altitude -1371 meters

(4500 ft); *Flight line spacing - 498.38 meters w/50% overlap; *Scan frequency - 21 Hz; *Firing rate - 25 kHz; *Scan angle

- 20 degrees; *Ground speed - 140 knots. When complete, the raw data was delivered to Spatial Systems.

Process Date/Time: 2004-01-20 00:00:00

Process Step 2

CC ID: 1133651

LIDAR Data Processing. Computational Consulting Systems. The First and Last Return data was delivered to

CCS in large blocks of data. CCS processed the data using both the First and Last Returns, removed artifacts using automated

and manual techniques, reprojected the data into the client-specified X, Y, Z text files using the 1200 meter x 1800 meter

tiles, NAD 83 meters, NAVD 88 meters. CCS also generated the Intensity Imagery using the client-specified USGS 3.75' tiling

scheme. The data products were delivered to SSA for quality assurance testing, formatting and final delivery.

Process Date/Time: 2004-01-20 00:00:00

Process Step 3

CC ID: 1133652

LIDAR Data Post Processing. Spatial Systems Associates. SSA digitized the shoreline from the Intensity

Imagery for the purposes of delineating a shoreline. Any LIDAR points that fell seaward of this shoreline were assigned the

value of zero (0). In addition to the shoreline, SSA delineated upland ponds using the same technique and assigned all LIDAR

points that fell within the water area the value of the lowest observed point close to the shore. The observed elevation

values were not lost - a fourth field in the data file was added for the assigned value. SSA also performed a variety of QA

procedures to determine if the point density was within expected ranges; that each tile was completely filled; that all tiles

were accounted for, and that the tiles were named in accordance with client specifications.

Process Date/Time: 2004-01-20 00:00:00

Process Step 4

CC ID: 1133653

LIDAR Data Check Point Surveys. NXL Construction Services. NXL was contracted to acquire the check-points in

the 5 different land cover classes. SSA provided NXL with maps of each area where a check-point was to be located. The points

were scattered throughout the project area. NXL was permitted the latitude to select the exact location based on field

conditions, provided the points were generally within a 1 mile radius of the chosen location and that the land cover class

was the same as the one specified. The land cover classes were: Grass/Ground, High Grass/Crops, Brush/Low Trees, Forest,

and Urban/Pavement.

Process Date/Time: 2004-01-20 00:00:00

Process Step 5

CC ID: 1133654

LIDAR Data Quality Assurance. Dewberry LLC was provided with the check-point and LIDAR Bare Earth Mass Points

data to perform their independent quality assurance work. They performed detailed analyses to determine if the vertical accuracy

with within specifications and examined the data for flight, data collection and processing inconsistencies. Neither the flight

vendor (Airborne 1) nor the processing vendor (CCS) was given access to the check-point data. The entire accuracy report can be

found at

Process Date/Time: 2004-01-20 00:00:00

Process Step 6

CC ID: 1133655

The NOAA Office for Coastal Management (OCM) received ASCII files containing the bare-earth elevation and intensity

data from Maryland Department of Natural Resources. OCM performed the following processing on the data to make it available

within the Lidar Data Retrieval Tool (LDART):

1. The data were projected from Maryland State Plane coordinates to geographic decimal degrees using the General Cartographic

Transformation Package.

2. The lat, long, MODZVAL and intensity values where extracted from the ASCII files and converted to the LDART binary format.

3. The data were converted to xyz text files

Process Date/Time: 2004-05-28 00:00:00

Catalog Details

Catalog Item ID: 49780
GUID: gov.noaa.nmfs.inport:49780
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:22+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