Photo Science, Inc.
Unpublished Material
State of Conneticut UTM Zone 18 (Classified LAS): LIDAR for the North East – ARRA and LiDAR for the North East Part II. (USGS Contract: G10PC00026, ARRA LIDAR Task Order Numbers) USGS Contract: G10PC00026 Task Order Number: G10PD02143 Task Order Numbers: G10PD01027 (ARRA) and G10PD02143 (non-ARRA)
model
The LiDAR for the North East Project, funded in large part by the American Recovery and Reinvestment Act (ARRA) of 2009, as well as, other funding sources was designed to help stimulate the U.S. economy and provide for more accurate floodplain mapping in the North East representing the start of a regional LiDAR collection program that served as a test case for a national elevation program. Lead by the United States Geological Survey's (USGS) National Geospatial Program Office and the State of Maine's Office of GIS with active collaboration and participation by other federal, state and local agencies resulted in LiDAR acquisition and processing of over 8,000 sq. miles of (LiDAR) data of a coastal zone spanning six North Eastern states, including Maine, New Hampshire, Massachusetts, Connecticut, Rhode Island, and New York. USGS's National Geospatial Technical Operations Center (USGS NGTOC) in Rolla, MO provided project management and quality control oversight for the project which consisted of two Task Orders issued to USGS contractor, GMR Aerial Surveys inc. d/b/a Photo Science (contractor), for task order execution through the use of USGS's Geospatial Products and Services Contract (USGS Contract: G10PC00026). Task Order specifications included state/area specific vertical accuracy, nominal post spacing and tide coordinated acquisition requirements.
Specific to the State of Conneticut UTM Zone 18, LiDAR was collected in the Winter 2010 through Winter 2011
at a 2 meter or better nominal post spacing (2m GSD) for approximately 455
square miles of Conneticut UTM Zone 18, while no snow was on the ground and rivers were at or below normal levels.
In order to post process the LiDAR data to meet task order specifications,
Photo Science subcontractor, The James W. Sewall Company, established a total of 11 control
points that were used to calibrate the LIDAR to known ground locations established throughout
the Conneticut UTM Zone 18 project area. Additionally, Sewall established twenty (20) quality control
"blind" check points using survey grade, dual frequency GPS receivers throughout the
Conneticut UTM Zone 18 project area and the contractor supplied the coordinate and elevation
data values for each point to USGS to independently validate theses required vertical
accuracies. These points were not used by the Contractors production team duing any
phase of the project. Conneticut UTM Zone 18 data was developed based on a horizontal projection/datum
of UTM NAD83 (2007), UTM Zone 18, meters and vertical datum of NAVD1988 (GEOID09), meters.
LiDAR data was delivered in RAW flightline swath format, processed to create Classified
LAS 1.2 Files formatted to 598 individual 1500m x 1500m tiles, Hydro Flattening Breaklines
in Esri shape file format, and corresponding 2.0 meter gridded Raster DEM Files tiled to
the same 1500m x 1500m schema. LiDAR Data was originally delivered to USGS for quality
control validation under USGS Delivery Lot 4. The lineage (metadata), positional, content
(completeness), attribution, logical consistency, and accuracies of all digital elevation
data produced conform to the specifications stipulated in USGS Task Orders G10PD01027 (ARRA)
and G10PD02143 (non-ARRA) and the U.S. Geological Survey National Geospatial Program Base
LiDAR Specification, Version 12.
Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images,
Breaklines and Raster DEM.
20101220
20111202
20111203
20111209
20111211
ground condition
Unknown
-73.7301624
-73.0807282
41.3793774
40.9786945
none
model
LiDAR
LAS Point Cloud
remote sensing
None
CT
US
None
None. However, 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 it's limitations. Acknowledgement of the U.S. Geological Survey would be
appreciated for products derived from these data.
Photo Science, Inc. flew the LiDAR and processed the data. MicroStation Version 8; TerraScan Version 11; ALS Post Processor 2.70 Build#15; TerraModeler Version 11;
GeoCue Version 7.0.34.5; Optech DashMAP 5.1000; Windows XP Operating System
Photo Science, Inc.
Unpublished Material
State of Conneticut UTM Zone 18 (Raster DEM): LIDAR for the North East – ARRA and LiDAR for the North East Part II. (USGS Contract: G10PC00026, ARRA LIDAR Task Order Numbers) USGS Contract: G10PC00026 Task Order Number: G10PD02143 Task Order Numbers: G10PD01027 (ARRA) and G10PD02143 (non-ARRA)
model
Photo Science, Inc.
Unpublished Material
State of Conneticut UTM Zone 18 (Hydro Breaklines): LIDAR for the North East – ARRA and LiDAR for the North East Part II. (USGS Contract: G10PC00026, ARRA LIDAR Task Order Numbers) USGS Contract: G10PC00026 Task Order Number: G10PD02143 Task Order Numbers: G10PD01027 (ARRA) and G10PD02143 (non-ARRA)
model
Photo Science, inc.
Unpublished Material
State of Conneticut UTM Zone 18: LIDAR for the North East – ARRA and LiDAR for the North East Part II. (USGS Contract: G10PC00026, ARRA LIDAR Task Order Numbers) USGS Contract: G10PC00026 Task Order Number: G10PD02143 Task Order Numbers: G10PD01027 (ARRA) and G10PD02143 (non-ARRA)
model
The project area required LiDAR to be collected on 2.0 meter GSD
or better and processed to meet a bare earth vertical accuracy of 15.0 centimeters
RMSEz or better.
Classified LAS files were tested by Photo Science for both vertical and horizontal accuracy.
All data is seamless from one tile to the next, no gaps or no data areas.
Datasets contain complete coverage of tiles.
Classified LAS files were tested by Photo Science for both vertical and horizontal
accuracy. All data is seamless from one tile to the next, no gaps or no data areas.
The vertical unit of the data file is in decimal meters with 2-decimal point precision.
The reported RMSEz value was determined using the calibration control points, and not the Blind Control. The calibration control
points are the same points that were used to remove any bias in the dataset before bare earth editing.
The listed RMSEz value shown below was calculated from the ground (ASPRS Class 2) data in the final Classified LAS file.
0.100
RMSE in meters
James W. Sewall
2012
Control
digital data
hard drive
2011
2012
ground condition
CTRL
Control points are uses as a known elevation to adjust the LiDAR data to the surface.
Photo Science, Inc.
2012
LiDAR
digital data
hard drive
20101220
20111202
20111203
20111209
20111211
ground condition
LiDAR
LiDAR points were used to produce the deliverables.
Control Process: James W. Sewall Company was contracted by Photo Science, Inc. to
locate a total of 11calibration control used in the post processing of the LiDAR data as well as 20 quality assurance check points for the state of Conneticut UTM Zone 18. The points
were located on relatively flat terrain on surfaces that generally consisted of grass,
gravel or bare earth. See Final Survey Reports for additional collection parameters and methodologies.
Applanix 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. POSPac MMS provides
the smoothed best estimate of trajectory (SBET) that is necessary
for Optech's post processor to develop the point cloud from the
LiDAR missions. The point cloud is the mathematical three dimensional
collection 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 manipulated within the Optech software; GeoCue,
TerraScan, and TerraModeler software was 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 was manually reviewed and any remaining artifacts removed
using functionality provided by TerraScan and TerraModeler.
All ground (ASPRS Class 2) LiDAR data inside of the Lake Pond and Double Line Drain hydro flattening
breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality.
A buffer of 1 meter was also used around each hydro flattened feature to classify these ground (ASPRS Class 2)
points to ignored ground (ASPRS Class 10). All Lake Pond Island and Double Line Drain Island features were
checked to ensure that the ground (ASPRS Class 2) were reclassified to the correct classification after the
automated classification was completed.
A new class has been added to the dataset to represent the bare water of the ocean
areas collected throughout the project area. ASPRS Class 14 is being used to represent the bare water
ocean surface. While attempts were made to remove all extraneous features above the surface
of the water, there may be above surface features classified to this class. Some islands below the required
collection specifications have been classified to this class as well. This class was also used
during the creation of the ERDAS Imagine Raster DEM files. The Ocean Shoreline and Ocean Island
breaklines were used to complete the automated classification of these classes within the final LAS files.
All overlap data was processed through automated functionality provided by
TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was
classified to Class 17 (USGS Overlap Default), Class 18 (USGS Overlap Ground), Class 25 (USGS Overlap Water),
and Class 30 (USGS Overlap Bare Water). These classes were created through automated processes only
and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to
trip the Withheld bit within various software packages. These processes were reviewed and accepted by USGS through
multiple conference calls and pilot study areas.
Data was then run through additional macros to ensure deliverable classification
levels matching the ASPRS LAS Version 1.2 Classification structure. GeoCue functionality was then
used to ensure correct LAS Versioning. In-house software was used as a final
QA/QC check to provide LAS Analysis of the delivered tiles. QA/QC checks were performed on a per tile
level to verify final classification metrics and full LAS header information.
LiDAR
2012
LiDAR post-processed data
Universal Transverse Mercator
18
0.99960000
-75.00000000
0.00000000
500000.00000000
0.0
coordinate pair
2.0
2.0
meters
North American Datum of 1983
World Geodetic System 1984
6378137.000000000000000000
298.257223563000030000
LAS 1.2 files (ASPRS Classes (1,2,7,9,10,14,17,18,25,30)
All deliverables meet specifications in contract. LAS Files meet ASPRS and USGS Classification Standards.
20120329
Photo Science, Inc.
Michael Shillenn
mailing and physical address
523 Wellington Way, Suite 375
Lexington
KY
40503
USA
859-277-8700
mshillenn@photoscience.com
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998