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Short Citation:
OCM Partners, 2024: 2015 City of Portland, Maine, Lidar, https://www.fisheries.noaa.gov/inport/item/49410.

Item Identification

Title: 2015 City of Portland, Maine, Lidar
Short Name: City_of_Portland_2015_DEM_m6270_metadata
Status: Completed
Publication Date: 2017-04-13
Abstract:

2015 City of Portland Maine Lidar Data Acquisition and Processing

Woolpert Order No. 75564

Contractor: Woolpert, Inc.

This task is for a high resolution data set of lidar covering approximately 21 square miles of the City of Portland, Maine.

The lidar data was acquired and processed under the requirements identified in this task order. Lidar data is a remotely sensed high resolution elevation data collected by an airborne platform. The lidar sensor uses a combination of laser range finding, GPS positioning, and inertial measurement technologies. The lidar systems collect data point clouds that are used to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 0.5 meters. The final products include classified LAS, four (4) feet pixel raster DEMs of the bare-earth surface in ERDAS IMG Format, and 8-bit intensity images. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Additional deliverables include hydrologic breakline data, control data, tile index and FGDC project level metadata in .xml format. Ground conditions: Water at normal levels; no unusual inundation; no snow; leaf off. This metadata record is for the DEM data served by the NOAA Digital Coast.

Purpose:

The purpose of this project is to provide lidar and lidar derived products for the task order 2015 City of Portland Maine Lidar.

Notes:

12079

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > TOPOGRAPHICAL RELIEF MAPS
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
None Project Level

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > MAINE

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: As Needed
Data Presentation Form: Lidar
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of the NOAA Office for Coastal Management, City of Portland, Woolpert, or their partners. Woolpert prepared the original data as set forth in the Scope of Services, in accordance with reasonable care and due diligence as set forth in this Agreement, however, due to the easily alterable nature of electronic media, files, documents, and other deliverables, Woolpert, Inc. makes no warranties, either expressed or implied, with respect to the accuracy, completeness, merchantability, or fitness for any particular purpose, including, but not limited to, use of any/all data as described within this metadata file, by any user of this data. Any use will be at the end-user's sole risk.

Data Set Credit: Woolpert flew and processed the original lidar data

Support Roles

Data Steward

CC ID: 661066
Date Effective From: 2017-04-13
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: 661068
Date Effective From: 2017-04-13
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: 661069
Date Effective From: 2017-04-13
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: 661067
Date Effective From: 2017-04-13
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: 1289391
W° Bound: -70.347905
E° Bound: -70.237341
N° Bound: 43.727922
S° Bound: 43.635127

Extent Group 1 / Time Frame 1

CC ID: 1289390
Time Frame Type: Discrete
Start: 2015-05-10

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1289387

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: 1289388

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:26856
EPSG Name: NAD83(HARN) / Maine West (ftUS)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6256.

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6270.

;

Data Access Constraints:

No restrictions apply to this 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 its limitations.

Distribution Information

Distribution 1

CC ID: 720732
Start Date: 2023-08-15
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6270
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2017-04-13 - Present)
File Name: Customized Download
Description:

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

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 720733
Start Date: 2023-08-15
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/MEGIS_Portland_ME_DEM_2015_6270/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2017-04-13 - Present)
File Name: Bulk Download
Description:

Simple download of data files.

File Type (Deprecated): GeoTIFF
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 720735
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 720736
URL: https://coast.noaa.gov
URL Type:
Online Resource

URL 3

CC ID: 720737
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/6256/supplemental/2015_portland_lidar_extent.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz
Description:

This graphic shows the lidar footprint for the 2015 City of Portland, Maine, lidar project

Activity Log

Activity Log 1

CC ID: 661083
Activity Date/Time: 2017-04-07
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 661082
Activity Date/Time: 2017-11-14
Description:

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

Activity Log 3

CC ID: 718109
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 720734
Activity Date/Time: 2018-02-13
Description:

Partial upload to move data access links to Distribution Info.

Data Quality

Horizontal Positional Accuracy:

Compiled to meet 1.091 ft horizontal accuracy at 95 percent confidence level.; Quantitative Value: 0.333 meters, Test that produced the value: Lidar system specifications

Vertical Positional Accuracy:

Non-vegetated Vertical Accuracy (NVA) compiled to meet 0.297 ft NVA at a 95 percent confidence level, derived according to NSSDA, using 0.152 ft (RMSEz) x 1.96000 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines against the TIN and ground points.; Quantitative Value: 0.09 meters, Test that produced the value: Compiled to meet NVA at a 95 percent confidence level in meters.

Completeness Report:

The lidar data is visually inspected for completeness to ensure that are no void areas or missing data.

Conceptual Consistency:

All formatted data cover the entire area specified for this project and are validated using a combination of commercial lidar processing software, GIS software, and proprietary programs to ensure proper formatting and loading prior to delivery.

Lineage

Sources

Hydrologic breakline deliverable processing

CC ID: 1289375
Publish Date: 2015-10-13
Extent Type: Discrete
Extent Start Date/Time: 2015-05-11
Source Contribution:

This data set is the project specified hydrologic breakline deliverable. | Type of Source Media: 3-d breakline dataset

Lidar acquisition

CC ID: 1289376
Publish Date: 2015-10-13
Extent Type: Discrete
Extent Start Date/Time: 2015-05-10
Source Contribution:

This data set is the project specified acquired point cloud data. | Type of Source Media: Lidar dataset

Lidar deliverable processing

CC ID: 1289377
Publish Date: 2015-10-13
Extent Type: Discrete
Extent Start Date/Time: 2015-05-11
Source Contribution:

This data set is the project specified lidar deliverables. | Type of Source Media: Lidar dataset

Survey Control Acquisition

CC ID: 1289378
Publish Date: 2015-10-13
Extent Type: Discrete
Extent Start Date/Time: 2015
Source Contribution:

This data set is the project specified acquired ground control and QAQC control data. | Type of Source Media: Control dataset

Tile index and data extent

CC ID: 1289379
Publish Date: 2015-10-13
Extent Type: Discrete
Extent Start Date/Time: 2015-05-11
Source Contribution:

This data set is the project specified tile index and data extent. | Type of Source Media: vector dataset

Process Steps

Process Step 1

CC ID: 1289380
Description:

Using two Leica ALS70 (lidar) systems on board a Cessna 310 aircraft, high density data, at a nominal pulse spacing (NPS) of 0.5 meters, were collected for this task order (approximately 21 square miles). Leica Specs- AGL = 1,829 meters - Aircraft Speed = 140 Knots, Field of View (Full) = 28 degrees, Pulse Rate = 293 kHz, Scan Rate = 52.5 Hz, with an average side lap of 27.7%. Multiple returns were recorded for each laser pulse along with an intensity value for each return. One (1) mission was flown on May 10, 2015. One (1) Global Navigation Satellite System (GNSS) Base Station was used in support of the lidar data acquisition. Specific information regarding latitude, longitude, and ellipsoid height to the L1 phase center is included in the lidar processing report. Data for the task order is referenced to the NAD1983 (HARN) StatePlane Maine West FIPS 1802 in U.S. Survey Feet. The Vertical Datum is in NGVD29 with units in U.S. Survey Feet. Once the data acquisition and GPS processing phases are complete, the lidar data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the project. The SBET was used to reduce the lidar slant range measurements to a raw reflective surface for each flight line. The coverage was classified to extract a bare earth digital elevation model (DEM) and separate last returns. The ALS70 calibration and system performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway. The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of lidar data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw lidar data is reduced using the refined misalignment angles.

Process Date/Time: 2015-05-10 00:00:00
Source: Lidar acquisition

Process Step 2

CC ID: 1289381
Description:

Control used in calibration/accuracy reporting was provided by the City of Portland and delivered as ESRI shapefile

Process Date/Time: 2015-01-01 00:00:00
Source: Survey Control Acquisition

Process Step 3

CC ID: 1289382
Description:

The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogeneous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" lidar returns. This process determined Default (Class 1), Ground (Class 2), Noise (Class 7), Water (Class 9), Ignored Ground (Class 10), Overlap Default (Class 17) and Overlap Ground (Class 18). The bare-earth (Class 2 - Ground) lidar points underwent a manual QA/QC step to verify the quality of the DEM as well as a peer-based QC review. This included a review of the DEM surface to remove artifacts and ensure topographic quality. Classification of water (class 9) and ignored ground (class 10) was completed via the use of the hydrologic breaklines collected for the hydro-flattening phase. The overlap classes were determined by first identifying the overlapping areas and reclassifying the LAS data by offset from a corridor. This allows the returns located on the edge of the swath to be removed from the bare earth coverage in an effort to produce a more uniform data density. The returns determined to be overlap including overlap default, ground, water, and ignored ground are then applied an overlap flag and reclassified to their respective standard classification value. The surveyed ground control points are used to make vertical adjustments to the data set and to perform the accuracy checks and statistical analysis of the lidar dataset. Supervisory QC monitoring of work in progress and completed editing ensured consistency of classification character and adherence to project requirements across the entire project area. The resulting deliverables for this task order consist of classified LAS file in LAS 1.4 format, 4 feet pixel size DEM files in ERDAS IMG format, 4 feet pixel size 8-bit Intensity files in GeoTIFF format, and Hydrologic Breakline data in ESRI shape file format.

Process Date/Time: 2015-05-11 00:00:00
Source: Lidar deliverable processing

Process Step 4

CC ID: 1289383
Description:

The compilation procedure included use of lidar intensity, bare earth surface model, point cloud data, and open source imagery in an effort to manually compile hydrologic features in a 2-d environment. Following the compilation phase, a separate process was used to adjust the breakline data to best match the water level at the time of the lidar collection. Any ponds and/or lakes were adjusted to be at or just below the bank and to be at a constant elevation. Any streams were adjusted to be at or just below the bank and to be monotonic. Manual QAQC and peer-based QC review was performed on all delineated data to ensure horizontal placement quality and on all adjusted data to ensure vertical placement quality. The final hydrologic breakline product was delivered in ESRI shape file format and was also used in the processing of the DEM deliverable.

Process Date/Time: 2015-05-11 00:00:00
Source: Lidar deliverable processing

Process Step 5

CC ID: 1289384
Description:

Tile Size: 5,000 ft x 5,000 ft. The tile file name was derived from the southwest corner of each tile.s

Process Date/Time: 2015-05-11 00:00:00
Source: Tile index and data extent

Process Step 6

CC ID: 1289385
Description:

DEM data was received by NOAA/OCM from the City of Portland in Imagine format, State Plane NAD83(HARN) Maine West (zone 1802) with vertical feet referenced to NGVD29. NOAA converted the data vertical meters referenced to NAVD88. Conversion from NGVD29 to NAVD88 was done with gdal_translate and VDatum.

Process Date/Time: 2017-03-16 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address: coastal.info@noaa.gov

Process Step 7

CC ID: 1289386
Description:

Data were converted to vertical feet using gdal_translate to be consistent with the horizontal units. Data were also converted to cloud optimized geotiff format and given vertical georeferencing in the same step.

Process Date/Time: 2023-08-15 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address: coastal.info@noaa.gov

Catalog Details

Catalog Item ID: 49410
GUID: gov.noaa.nmfs.inport:49410
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:13+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-10 18:55+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