2001 NCFMP Lidar: Phase 1A (Neuse, Pasquotank, Tar-Pamlico, White Oak River Basins)

This airborne LiDAR terrain mapping data was acquired January through March 2001. The data were collected for the floodplain

mapping program for the state of North Carolina. The data were collected for the state in three phases: 1, 2, and 3.

This metadata record describes that data that were in phase 1 of collection and fall within the Neuse, Pasquotank, Tar-Pamlico,

and White Oak River Basins in central and eastern North Carolina. This area consists of 33 counties which are listed below in

the Place Keywords field.

The data were received by the NOAA Office for Coastal Management from the U.S. Geological Survey (USGS) Center for Lidar

Coordination and Knowledge (CLICK). For data storage and Digital Coast provisioning purposes, the OCM converted the data

to geographic coordinates and ellipsoid (Geoid99) elevations. The data are unclassified.

Original contact information:

Contact Org: NC Floodplain Mapping Program

Phone: 919-715-0408

Email: hmorgan@ncem.org

These data were collected and derived by the North Carolina Floodplain Mapping Program (www.ncfloodmaps.com) as part of its

effort to modernize FEMA Flood Insurance Rate Maps (FIRM) statewide. Although created for specific use in the engineering

aspects of floodplain delineation, the data were also developed to address the elevation data requirements of the broader

geospatial data user community. The North Carolina Floodplain Mapping Program was established in response to the extensive

damage caused by Hurricane Floyd in 1999.

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A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1397/supplemental/nc2001_ncfmp_phase1b_m1397.kmz

The Lidar Accuracy Assessment Reports for these data are available by county and may be viewed at:

http://portal.ncdenr.org

Files in LAZ format (classified as 1, unclassified)

none

Any conclusions drawn from the analysis of this information are not the responsibility of NC Floodplain Mapping Program,

EarthData International, the NOAA Office for Coastal Management, or its partners.

None

N/A

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1397

;

None

Users should be aware that temporal changes may have occurred since this data set was collected and that 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.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722

LIDAR full returns were compared with NCGS QA/QC checkpoints using only single and final returns per pulse. A vertical bias was

acquired after airport calibration based on this comparison. For the NC Floodplain Mapping Program, the vertical accuracy for

coastal counties is less than or equal to 20 cm RMSE. For mainland counties, the vertical accuracy of the elevation data is less

than or equal to 25 cm RMSE. More information about the Quality Control reports and a summary of the quality control checks for

each county can be found at http://portal.ncdenr.org/web/lr/geodetic/floodplaininfo.

| Quantitative Value: 20 | Quantitative Test Explanation: Less than or equal to 20 cm RMSE of bare earth LIDAR points compared with independent checkpoints.

LIDAR full return mass points were compared with surveyed elevations provided by independent contractors to the NCGS.

More information about the Quality Control reports is available at http://portal.ncdenr.org/web/lr/geodetic/floodplaininfo.

Numerous internal quality assurance/quality control steps taken to ensure the quality of the LIDAR terrain data to

meet the bare earth requirements and RMSE accuracy standards in the NC Floodplain Mapping Program.

Step 1. Preprocessing

Step 2. Post-Automated Editing QC (Data Evaluation)

Step 3. QC Check of Tiles

Step 4. Manual Editing (Hillshade Checks / Peer Review)

Step 5. QC and Tile Edge Matching

Step 6. Final EarthData QC

Step 7. Comparisons of Independent Field Survey Data with LIDAR Data

; Quantitative Value: 2 meters, Test that produced the value: RMSE (m) of bare earth LIDAR points compared with independent checkpoints.

LIDAR full return mass points were compared with surveyed elevations provided by independent contractors to the

NCGS. A vertical bias was acquired after airport calibration based on this comparison. For the NC Floodplain Mapping Program,

the vertical accuracy for coastal counties is less than or equal to 20 cm RMSE. For mainland counties, the vertical accuracy

of the elevation data is less than or equal to 25 cm RMSE.

The RMSE value for each county is available in the Lidar Accuracy Assessment Report. These reports are available by county and may be viewed at:

http://portal.ncdenr.org/web/lr/geodetic/floodplaininfo

Numerous internal quality assurance/quality control steps were taken to ensure the quality of the LIDAR terrain data

to meet the bare earth requirements and RMSE accuracy standards in the NC Floodplain Mapping Program.

Step 1. Preprocessing

Step 2. Post-Automated Editing QC (Data Evaluation)

Step 3. QC Check of Tiles

Step 4. Manual Editing (Hillshade Checks / Peer Review)

Step 5. QC and Tile Edge Matching

Step 6. Final EarthData QC

Step 7. Comparisons of Independent Field Survey Data with LIDAR Data

; Quantitative Value: 0.20 meters, Test that produced the value: RMSE (m) of bare earth LIDAR points compared with independent checkpoints.

The full return mass points contain voids where insufficient energy was reflected from the surface to generate a valid return from

the terrain. Voids in the full return mass points tend to occur in water bodies. Wet sand and certain types of vegetation can also

cause voids or anomalous elevations.

Data was vertically adjusted based on RMSE and mean difference from control report.