2005 US Army Corps of Engineers (USACE) National Coastal Mapping Program Topo/Bathy Lidar: Delaware, Maryland, New Jersey, New York, North Carolina and Virginia

Simple download of data files.

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

3D viewer for the dataset using the Potree javascript app in a browser.

Date that the source FGDC record was last modified.

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.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

This is an xyz dataset collected and provided by CESAM-OP-J, JALBTCX.

| Source Geospatial Form: globe | Type of Source Media: disc

FOR DE,MD,NJ,VA DATA:

These data were collected using a SHOALS-1000T system. It is owned and operated by Fugro Pelagos performing contract survey services for the US Army Corps of Engineers. The system collects topographic lidar data at 10kHz and hydrographic data at 1kHz. The system also collects RGB imagery at 1Hz. Aircraft position, velocity and acceleration information are collected through a combination of Novatel and POS A/V equipment. Raw data are collected and transferred to the office for downloading and processing in SHOALS GCS software. The data were collected and processed in geographic coordinates and ellipsoid heights. The positions are provided relative to NAD83 in decimal degrees of longitude and latitude. The heights were converted from ellipsoid to geoid heights (NAVD88) using NGS' Geoid03 model file "g2003u08.bin" with the results in meters. GPS data are processed using POSPac software and the results are combined with the lidar data to produce 3-D positions for each lidar shot. These data are edited using Fledermaus software where anomalous data are removed from the dataset. The edited data are unloaded from SHOALS GCS, converted from ellipsoid to orthometric heights, based on the GEOID03 model, and split into geographic tiles covering approximately 5km each. The process date for this data set is 20060406, which is listed below as the process date for this process step.

FOR NY,NC DATA:

Acquisition

Data were acquired using a SHOALS-1000T. Sensor orientation was measured using a POS AV 410, while images were acquired at 1Hz using a Duncantech DT4000 digital camera. Prior to survey, PDOP was checked and missions planned to avoid PDOP greater than 3.5. During survey, the plane was always within 30km of a GPS ground control point, to provide a good quality position solution. Final positions were determined using a post-processed inertially aided Kinematic GPS (KGPS) solution. GPS ground control data were acquired at 1Hz.

Data received by the airborne system were continually monitored for data quality during acquisition operations. Display windows showed coverage and information about the system status. In addition, center waveforms at 5Hz were shown. All of this information allowed the airborne operator to assess the quality of data being collected.

Data were processed in the field to verify coverage and data quality. Data were processed using the SHOALS Ground Control System (GCS). The GCS includes links to Applanix POSPac software for GPS and inertial processing, and IVS Fledermaus software for data visualization, 3D editing and tie-line analysis. Data were processed in NAD83 horizontal and vertical datum. Data were later converted to the NAVD88 vertical datum using the GEOID03 model. Fugro in-house utilities were used to extract XYZ data from the native LIDAR files and split the data in to pre-defined boxes, each covering approximately 5km of shoreline. ASCII files include Longitude Latitude Elevation Date Time Intensity (Topo) or Depth Confidence (Hydro).

The NOAA Office for Coastal Management (OCM) received files in ascii format. The files contained lidar intensity and elevation measurements. OCM performed the following processing on the data to make it available within the Lidar Data Retrieval Tool (LDART):

1. Each hydro/topo last return ascii file was converted to las files. Default values for which there is no corresponding input were assigned as follows for each las elevation data record: intensity = 0, retn = 1, nret = 1, class = 0

2. The las files were sorted by latitude and the las header fields were updated.

3. The data were converted to ellipsoid.

Times had originally been stored as POSIX seconds when converted to LAS. This was switched to adjusted GPS time (GPS seconds - 1e9) to conform to the LAS 1.2 standard.

The data were classified using programs in the LAStools package. Steps included:

1) conversion to UTM zone 18

1b) reclassification of green laser points above ground (33 meters above the ellipsoid) to unclassified

2) noise classification with a step of 8

3) ground classification with lasground_new

4) height determination with lasheight

5) building and vegetation classification with lasclassify using a step of 4

6) conversion from UTM zone 18 to geographic

This was an automated process and manual editing of anomalies was not done. We do know that large buildings are sometimes missed in the building classification and end up as vegetation class.