49847
2011 FEMA Risk Mapping, Assessment, and Planning (Risk MAP) Lidar: Nashua River Watershed (Massachusetts, New Hampshire)
nh2011_nashua_river_m2513_metadata
Data Set
Published / External
49401
Lidar - partner (no harvest)
Project
Completed
2013-07-18
These data are the lidar points collected for FEMA Risk Mapping, Assessment, and Planning (Risk MAP) for the Nashua River Watershed.
This area falls in portions of Hillsborough County in New Hampshire and portions of Middlesex and Worcester counties in Massachusetts.
Using a Leica ALS60 LiDAR system, a total of 35 flight lines of high density (Nominal Pulse Spacing of 2.0 m) were collected over the Nashua
area which encompasses 530.3 square miles. A total of 3 missions were flown on May 6, 2011 and May 7, 2011. One airborne global
positioning system (GPS) base station was used to support the LiDAR data acquisition: FIT B.
The data were received by the NOAA Office for Coastal Management from NH GRANIT. For data storage and Digital Coast provisioning purposes
the data were:
1. Converted from UTM Zone 19, meters, NAD83 to geographic coordinates.
2. Converted from NAVD88 (Geoid09), meters to ellipsoid heights, using Geoid09
3. Converted overlap points that were classified as 11 to class 12 (Overlap).
Data available for download from the Digital Coast include the following classifications:
1. 1 (Unclassified)
2. 2 (Ground)
3. 7 (Low Point Noise)
4. 9 (Model Key Points)
5. 12 (Overlap)
Original contact information:
Contact Org: NH GRANIT
Phone: 603-862-1792
Email: granit@unh.edu
Provide high resolution terrain elevation and land cover elevation data. Terrain data is used to represent the topography of a watershed
and/or floodplain environment and to extract useful information for hydraulic and hydrologic models.
10491
The FEMA Nashua River HUC 8 LiDAR FY2010 report may be accessed at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2513/supplemental/Nashua_River_HUC_8_01070004_Terrain_TSDN.pdf
A footprint of this data may be viewed in Google Earth at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2513/supplemental/2011_FEMA_Nashua_River_Watershed_Lidar.kmz
Theme
ISO 19115 Topic Category
elevation
Theme
Bare Earth
Theme
Ground Control
Theme
Land Surface
Theme
Point Cloud
Office for Coastal Management
Charleston
SC
Data Set
Unknown
las
The Terrain data package is made up of several data themes containing primarily spatial information.
These data supplement the Elevation datasets by providing additional information to aid flood risk evaluation and flood hazard area delineations.
Appendix M of FEMA Guidelines and Specifications for FEMA Flood Hazard Mapping Partners contains
a detailed description of the data themes and references to other relevant information.
No warranty expressed or implied is made by FEMA regarding the utility of the data on any other system nor shall the act of distribution
constitute any such warranty. Any conclusions drawn from the analysis of this information are not the responsibility of FEMA, NH GRANIT,
the NOAA Office for Coastal Management or its partners.
Acknowledgement of FEMA would be appreciated in products derived from these data. This digital data is produced for the purposes of
updating/creating a DFIRM database. Ground control and quality control checkpoints were collected by CompassData, Inc. LiDAR was acquired
and processed by Photo Science, Inc. Quality Control testing was performed by CompassData, Inc. Quality Assurance testing was conducted
by Greenhorne & O'Mara, Inc. All firms were under contract to STARR, A Joint Venture which held the FEMA contract and task order for this work.
50234
Terrain\2142865\SupplementalData\GroundControl Nashua
Terrain\2142865\SupplementalData\GroundControl Nashua
Published / External
Completed
Ground Control Survey for LiDAR collection | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50235
Terrain\2142867\Bare_Earth
Terrain\2142867\Bare_Earth
Published / External
Completed
LAS 1.2 files | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50236
Terrain\2142865\SupplementalData\FVA_CVA Nashua
Terrain\2142865\SupplementalData\FVA_CVA Nashua
Published / External
Completed
Survey for Horizontal and Vertical LiDAR QC | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50237
Terrain\2142866\SupplementalData\Nashua_Collection_Area
Terrain\2142866\SupplementalData\Nashua_Collection_Area
Published / External
Completed
Area Spatial File | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50238
Terrain\2142866\All_Returns
Terrain\2142866\All_Returns
Published / External
Completed
LAS 1.2 files | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50239
Terrain\2142866\SupplementalData\Nashua_PreFlight Report
Terrain\2142866\SupplementalData\Nashua_PreFlight Report
Published / External
Completed
Digital Document | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50240
Terrain\2142866\SupplementalData\Nashua_PostFlight Report
Terrain\2142866\SupplementalData\Nashua_PostFlight Report
Published / External
Completed
Digitial Document | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50241
Terrain\2142866\SupplementalData\Nashua_Tile_Index
Terrain\2142866\SupplementalData\Nashua_Tile_Index
Published / External
Completed
Area Spatial File | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50242
Terrain\2142867\SupplementalData\Region 1 Nashua Testing Results FVA CVA
Terrain\2142867\SupplementalData\Region 1 Nashua Testing Results FVA CVA
Published / External
Completed
Digital Document | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
50243
Terrain\2142867\SupplementalData\R1_Nashua_Terrain_TSDN
Terrain\2142867\SupplementalData\R1_Nashua_Terrain_TSDN
Published / External
Completed
Digital Document | Description Source:
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix M: Data Capture Standards
and Data Capture Guidelines
Converted from FGDC using 'fgdc_to_inport_xml_entity.pl' script.
Data Steward
2013-07-18
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Distributor
2013-07-18
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Metadata Contact
2013-07-18
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Point of Contact
2013-07-18
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Ground Condition
-71.987399
-71.425869
42.820656
42.315652
Range
2011-05-06
2011-05-07
Yes
Unclassified
This data can be obtained on-line at the following URL:
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2513
This data set is dynamically generated based on user-specified parameters.
;
None
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.
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2513
Customized Download
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2513/index.html
Bulk Download
Simple download of data files.
https://coast.noaa.gov
Online Resource
https://coast.noaa.gov/dataviewer
Online Resource
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2513/supplemental/Nashua_River_HUC_8_01070004_Terrain_TSDN.pdf
Lidar Report
Online Resource
pdf
Link to the lidar report.
2017-03-20
Date that the source FGDC record was last modified.
2017-11-14
Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.
2018-02-08
Partial upload of Positional Accuracy fields only.
2018-03-13
Partial upload to move data access links to Distribution Info.
Deliverables were tested by for both vertical and horizontal accuracy. The vertical unit of the data file is in meters with 2-decimal
point precision.
Consolidated Vertical Accuracy (CVA) tested 18.5 cm at 95th percentile in: open terrain, forest terrain, and urban terrain. The Root Mean
Square Error (RMSE) for the elevation differences between GPS control points and lidar points is 9.4 cm calculated with 20 supplemental
vertical accuracy (SVA) points.
Fundamental Vertical Accuracy (FVA) tested 17.2 cm at 95 percent confidence level in open terrain using RMSEz x 1.9600. The Root Mean Square
Error (RMSE) for the elevation differences between GPS control points and lidar points is 8.8 cm calculated with 20 FVA points.
The Region_1_Nashua_Testing_Results_FVA_CVA.pdf may be accessed at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2513/supplemental/Region_1_Nashua_Testing_Results_FVA_CVA.pdf
; Quantitative Value: 0.088 meters, Test that produced the value:
The Root Mean Square Error (RMSE) for the elevation differences between GPS control points and
lidar points in open terrain is 8.8 cm calculated with 20 Fundamental Vertical Accuracy (FVA) points.
Survey data have been checked for completeness; points have been collected in correct vegetation units, and distributed
throughout the AOI. The terrain data have been checked for completeness against AOI polygons. No gaps as defined by FEMA Procedural Memo
No. 61 are known to exist within the dataset.
Survey data have been confirmed to be in proper units, coordinate systems and format. The terrain data have been
confirmed as complete LAS format data files. Header files are in proper LAS format with content as specified by FEMA Procedural Memo No. 61.
All_Returns
2011-01-01
Discrete
2011-07-15
Point Cloud (All Returns) LAS point files named according to Nashua Tile Index. | Type of Source Media: DIGITAL
Bare_Earth
2011-01-01
Discrete
2011-07-15
Bare Earth LAS point files named according to the Nashua_Tile_Index. | Type of Source Media: DIGITAL
FVA_CVA Nashua
2011-01-01
Discrete
2011-01-28
Quality Assurance points to confirm LiDAR data meets vertical accuracy requirements. | Type of Source Media: DIGITAL
Ground_Control Nashua
2011-01-01
Discrete
2011-01-28
Control points for tying LiDAR data to the ground surface. | Type of Source Media: DIGITAL
Nashua_Collection_Area
2011-01-01
Discrete
2011-07-15
Shapefile of Nashua LiDAR acquisition area. | Type of Source Media: DIGITAL
Nashua_PostFlightReport
2011-01-01
Discrete
2011-07-15
Document contains the acquisition and calibration report for the LiDAR acquisition | Type of Source Media: DIGITAL
Nashua_PreFlightReport
2011-01-01
Discrete
2011-07-15
Document contains the operations plans for the LiDAR acquisition. | Type of Source Media: DIGITAL
Nashua_Tile_Index
2011-01-01
Discrete
2011-07-15
Shapefile of tile index used to populate and reference the LAS tiled data. | Type of Source Media: DIGITAL
R1_Nashua_Terrain_TSDN
2011-01-01
Discrete
2011-07-15
Contains complete narrative on the acquisition and processing of the LiDAR dataset, includes area diagrams,
reports and metadata.
| Type of Source Media: DIGITAL
Region 1 Nashua Testing Results FVA CVA
2011-01-01
Discrete
2011-07-15
Document contains QC test results for both FVA and CVA blind check point tests against open area and bare earth
surfaces generated from All Returns and Bare Earth (respectively) LAS points.
| Type of Source Media: DIGITAL
1
GPS based surveys were utilized to support both processing and testing of LiDAR data within FEMA designated Areas of Interest (AOIs).
Geographically distinct ground points were surveyed using GPS technology throughout the AOIs to provide support for three distinct tasks.
Task 1 was to provide Vertical Ground Control to support the aerial acquisition and subsequent bare earth model processing. To accomplish
this, survey-grade Trimble R-8 GPS receivers were used to collect a series of control points located on open areas, free of excessive or
significant slope, and at least 5 meters away from any significant terrain break. Most if not all control points were collected at street/road
intersections on bare level pavement.
Task 2 was to collect Fundamental Vertical Accuracy (FVA) checkpoints to evaluate the initial quality of the collected point cloud and to
ensure that the collected data was satisfactory for further processing to meet FEMA specifications. The FVA points were collected in
identical fashion to the Vertical Ground Control Points, but segregated from the point pool to ensure independent quality testing without
prior knowledge of FVA locations by the aerial vendor.
Task 3 was to collect Consolidated Vertical Accuracy (CVA) checkpoints to allow vertical testing of the bare-earth processed LiDAR data in
different classes of land cover, including: Open (pavement, open dirt, short grass), High Grass and Crops, Brush and Low Trees, Forest,
Urban. CVA points were collected in similar fashion as Control and FVA points with emphasis on establishing point locations within the
predominant land cover classes within each AOI or Functional AOI Group. In order to successfully collect the Forest land cover class,
it was necessary to establish a backsight and Initial Point with the R8 receiver, and then employ a Nikon Total Station to observe a
retro reflective prism stationed under tree canopy. This was necessary due to the reduced GPS performance and degradation of signal under
tree canopy. The R-8 receivers were equipped with cellular modems to receive real-time correction signals from the Keystone Precision
Virtual Reference Station (VRS) network encompassing the Region 1 AOIs. Use of the VRS network allowed rapid collection times
(~3 minutes/point) at 2.54 cm (1 inch) initial accuracy. All points collected were below the 16.5cm specification for testing 49cm,
High category LiDAR data. To ensure valid in-field collections, an NGS monument with suitable vertical reporting was measured using
the same equipment and procedures used for Control, FVA and CVA points on a daily basis. The measurement was compared to the NGS
published values to ensure that the GPS collection schema was producing valid data and as a physical proof point of quality of
collection. Those monument measurements are summarized in the Accuracy report included in the data delivered to FEMA.
2011-01-01T00:00:00
2
In order to meet FEMA budgetary requirements, AOIs were consolidated into Functional Groups: if AOIs were contiguous, they were treated
as one large AOI to allow collection of 20 FVA points and 15 additional CVA points across the group of AOIs. 20 FVA points are necessary
to allow testing to CE95 - 1 point out of 20 may fail vertical testing and still allow the entire dataset to meet 95% accuracy requirements.
In similar fashion, 20 CVA points are necessary to test to CE95 as discussed above. 15 CVA points were collected per AOI or per
Functional Group with the intention at the outset that 5 of the collected FVAs would perform double -duty as Open-class CVA points,
to total 20 CVAs per AOI or Functional Group.
The Functional Groups are as follows: Narragansett/Charles/Blackstone (northeast), Nashua, Blackstone (north and west), Quinnipiac,
Quincy/Suffolk (while included as part of the FEMA Charles AOI, was physically separated from the Charles AOI polygon and treated as an
independent functional area).
The following software packages and utilities were used to control the GPS receiver in the field during data collection, and then
ingest and export the collected GPS data for all points: Trimble Survey Controller, Trimble Pathfinder Office.
The following software utilities were used to translate the collected Latitude/Longitude Decimal Degree HAE GPS data for all
points into Latitude/Longitude Degrees/Minutes/Seconds for checking the collected monument data against the published NGS Datasheet
Lat/Long DMS values and into UTM NAD83 Northings/Eastings: U.S. Army Corps of Engineers CorpsCon, National Geodetic Survey Geoid09NAVD88.
MSL values were determined using the most recent NGS-approved geoid model to generate geoid separation values for each Lat/Long coordinate
pair. In this fashion, Orthometric heights were determined for each Control, FVA and CVA point by subtracting the generated Geoid Separation
value from the Ellipsoidal Height (HAE) for publication and use as MSL NAVD88(09).
2011-01-01T00:00:00
3
Using a Leica ALS60 LiDAR system, 35 flight lines of high density (Nominal Pulse Spacing of 2.0 m) were collected over the Nashua area
which encompasses 530.3 square miles. A total of 3 missions were flown on May 6, 2011 and May 7, 2011. One airborne global positioning
system (GPS) base station was used to support the LiDAR data acquisition: FIT B. Additional information can be found in the Post-Flight
Aerial Acquisition Report.
2011-01-01T00:00:00
4
Leica proprietary software was used in the post-processing of the airborne GPS and inertial data that is critical to the positioning
and orientation of the sensor during all flights. Pairing the aircraft raw trajectory data with the stationary GPS base station
data, this software yields the Leica IPAS TC (Inertial Positioning & Attitude Sensor - Tightly Coupled) smoothed best estimate of
trajectory (an SBET, in the Leica .sol file format) that is necessary for the Leica ALSPP post processing software to develop the
resulting geo-referenced point cloud from the LiDAR missions. The point cloud is the mathematical three dimensional composite of all
returns from all laser pulses as determined from the aerial mission. At this point this data is ready for analysis, classification,
and filtering to generate a bare earth surface model in which the above-ground features are removed from the data set.
The point cloud was created using Leica Post Processor software. GeoCue was used in the creation of some of the files needed in
downstream processing, as well as in the tiling of the dataset into more manageable file sizes. The TerraScan and TerraModeler
software packages are then used for the automated data classification, manual cleanup, and bare earth generation from this data.
Project specific macros were used to classify the ground and to remove the side overlap between parallel flight lines. All data
were manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. QT Modeler
was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for
both the All Point Cloud Data and the Bare Earth. In-house software was then used to perform final statistical analysis of the classes
in the LAS files.
2011-01-01T00:00:00
5
Point Cloud data is manually reviewed and any remaining artifacts are removed using functionality provided within the TerraScan
and TerraModeler software packages. Additional project specific macros are created and run within GeoCue/TerraScan to ensure correct LAS
classification prior to project delivery. Final Classified LAS tiles are created within GeoCue to confirm correct LAS versioning and
header information. In-house software is then used to check LAS header information and final LAS classification prior to delivery.
LAS Class 2 is used to check the independent QC points against the Triangulated LiDAR surface.
2011-01-01T00:00:00
6
The NOAA Office for Coastal Management received elevation and intensity data las files in LAS v1.2 format. The data were in UTM Zone 19, meters,
NAD83 coordinates and were vertically referenced to NAVD88 (Geoid09). The vertical units of the data were meters. OCM performed the following
processing for data storage and Digital Coast provisioning purposes:
1. Data were filtered for outliers using the lastools tool, las2las
2. Data points that were overlap points, but were classified as 11, were converted to class 12 (overlap), using the lastools tool, las2las
3. Data were converted from UTM Zone 19, meters, NAD83 to geographic coordinates.
4. Data were converted from NAVD88 (Geoid09) elevations, to ellipsoid elevations using Geoid09
5. Data were zipped to laz format
2013-07-01T00:00:00
50236
Entity
Terrain\2142865\SupplementalData\FVA_CVA Nashua
50234
Entity
Terrain\2142865\SupplementalData\GroundControl Nashua
50238
Entity
Terrain\2142866\All_Returns
50237
Entity
Terrain\2142866\SupplementalData\Nashua_Collection_Area
50240
Entity
Terrain\2142866\SupplementalData\Nashua_PostFlight Report
50239
Entity
Terrain\2142866\SupplementalData\Nashua_PreFlight Report
50241
Entity
Terrain\2142866\SupplementalData\Nashua_Tile_Index
50235
Entity
Terrain\2142867\Bare_Earth
50243
Entity
Terrain\2142867\SupplementalData\R1_Nashua_Terrain_TSDN
50242
Entity
Terrain\2142867\SupplementalData\Region 1 Nashua Testing Results FVA CVA
gov.noaa.nmfs.inport:49847
Anne Ball
2017-11-15T15:22:43
Rebecca Mataosky
2022-08-12T14:07:37
2022-03-16
OCM Partners
OCMP
1002
Public
No
2022-03-16
1 Year
2023-03-16