2009 USGS New Jersey Lidar: Mercer County

High accuracy LiDAR data covering Mercer County New Jersey (228 sq miles). These datasets will be the initial acquisition to support

general geospatial needs of the USGS and the New Jersey Department of Environmental Protection (NJ-DEP).

The purpose of the Mercer County Lidar project is to provide LiDAR data for New Jersey Department of Environmental Protection (NJ-DEP).

This project acquired and produced high accuracy bare-earth processed LiDAR data in LAS format and 1.0-meter Digital Elevation Models

(DEMs) in ArcGrid format for approximately 228 square miles of Mercer County.

10502

- Technical Acquisition Parameters:

Utilizing Leica ALS50 II laser systems which can collect data at laser pulse rates up to 150 KHz, Photo Science flew the project

area at 7,000 feet AGL and utilized a 19 degree full-angle field of view. Flights were accomplished nominally at 98 knots

(ground speed) with a pulse rate of 113,600Hz, collecting four returns per pulse. The scan rate was be set at 50.4Hz. These

settings resulted in a swath of 2,343 feet with maximum along track and cross track spacing of 3.28 feet (1.0 meters).

- Environmental Acquisition Conditions: Leaf-Off, snow free, non-flood conditions.

- Nominal Pulse density:

Average point density is 3.15 points per sq. Meter

Average point spacing is 0.56 meters.

- Calibration procedures:

Photo Science has created a significant boresight facility at the Frankfort, KY airport where the Lidar platforms are stationed

when not in service. Boresighting at this facility takes place with our Lidar sensors at numerous times throughout the year.

Additionally, a mini-calibration site was established at the Robbinsville Airport at the project site. Additional calibration

flights were conducted over this site to ensure accurate determination of the calibration parameters throughout the times of

acquisition.

- GPS:

Acquisition for this project was completed using the base station from the NGS database selected near the center of the

acquisition area to serve as control for all lifts. A ground based GPS receiver was occupied at the station during all aerial

collection. The published NGS positions of the base station and raw GPS observation data were used in the kinematic GPS

post-processing of all lifts to provide positioning for the point clouds produced for this project.

- Maximum and mean differential baseline lengths:

Nominal Maximum base line distance was approximately 20 Miles

Mean base line distance was approximately 11 Miles

- Geoid Model Used:

Geoid 03 was used for all height conversion from ellipsoidal to orthometric heights.

- Reference System:

Horizontal: New Jersey State Plane Coordinate System, 1983 North American Datum, feet

Vertical: North American Vertical Datum of 1988 (NAVD88), feet

The Lidar QA/QC Quantitative and Qualitative Assessment Report for this data set may be viewed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/546/supplemental/lidarqaqcreport_mercer_final.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/546/supplemental/2009_USGS_NJ_Lidar_Mercer_County.kmz

Attributes included: x,y,z to two significant digits; intensity and class as integers.

Also includes echo return, time stamp, etc.

LiDAR point data in LAS 1.1; ASPRS classfication scheme: Class 1 - Unclassified/Extracted Features; Class 2 - Bare Earth Ground;

Class 9 - water; Class 12 - overlap.

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

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;

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.

The following aspects of the LiDAR data was verified during the course of the project processing:

-Data accuracy and errors

-Anomaly checks through full-feature hillshades and 3-D modeling

-Post automated classification Bare-earth verification

-Final quality control of deliverable products ensuring integrity, graphical quality

Compiled to meet 1m horizontal accuracy

Using NSSDA standards, this LiDAR dataset will have a fundamental vertical accuracy of 35.32 cm at 95% confidence level, based on RMSE

of 18 cm in the open terrain land cover category.

Data completeness and integrity was verified.

All LAS formatted LiDAR data are validated to ensure that data on delivery media is in correct physical format and

is readable and correctly georeferenced and projected. Note that LiDAR intensity is not calibrated or normalized.