USGS
20071210
Classified LAS
Lidar data
Unknown
Unknown
Reston,VA
USGS
LIDAR-derived binary (.las) files containing classified points of all returns. We have 4 classifications Unclassified, Ground, Low Points and Water. The total area covers approximately 1,035 square miles. Thes tiles are delivered in Digital Ortho Quarter-Quarter Quad format.
Unknown
1) Geoid 2003
2) All of the GPS coordinates were referenced to the following NGS (Natioal Geodetic Survey) points designated as:
V 1439 (PID #AP0159)
F 1436 ((PID #AO0496)
G 1432 (PID #AZ0495)
ROW (PID #AO0338)
3) 6 GPS Base Stations were used for this project. Maximum baseline length to the end of the project boundary limits was approximately 24 miles and the mean baseline length was approximately 14 miles.
4) Nominal pulse density:
Area 1 = 41,000 Hz
Area 2 = 40,000 Hz
5) A LiDAR calibration or 'boresight' is performed on every mission to determine and eliminate systemic biases that occur within the hardware of the Leica ALS50 laser scanning system, the inertial measurement unit (IMU), and because of environmental conditions which affect the refraction of light. The systemic biases that are corrected for include roll, pitch, and heading.
In order to correct the error in the data, misalignments of features in the overlap areas of the lidar flightlines must be detected and measured. At some point within the mission, a specfic flight pattern must be flown which shows all the misalignments that can be present. Typically, Merrick flies a pattern of at least three opposing direction and overlapping lines, three of which provide all the information required to calibrate the system.
20071003
unknown
20080131
unknown
ground condition
As needed
-100.180551
-100.155940
28.125294
28.106593
None
LAS
LIDAR
Elevation
None
Mexican-Texas Border
Mexico
Texas
USA
None
2007
2008
none
none
USGS National Center for Earth Resources Observation & Science (EROS)
mailing and physical address
Customer Services, USGS National Center for Earth Resources Observation & Science (EROS)
Sioux Falls
South Dakota
57198-0001
USA
+001 605-594-6151
1-800-252-4547
+001 605-594-6933
+001 605-594-6589
custserv@usgs.gov
0800 - 1600 CT, M-F, -6 h GMT
none
Merrick & Company
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.5.1450
Verification of attribute accuracy of LIDAR data involves the use of filtering techniques. Auto-filtering uses algorithms to reclassify data in the point cloud. Hand-filtering involves the use of a technician working in a graphic environment to reclassify the erroneous points that may remain in the LIDAR point cloud after auto filter.
n/a
n/a
Calibrations of the LIDAR flightline data are performed; this process is known as boresighting. The flightlines are compared to evaluate both their relative and absolute accuracies.
This dataset contains unclassified returns of the LIDAR sensor. The sensor data was verified in MARS software to ensure complete coverage.
Horizontal accuracy is verified in three tests. During boresighting, adjoining flightlines are view in profile and hard edged features are observed and if necessary the flightlines are adjusted for good relative horizontal and vertical fit. The second test for horizontal accuracy is by comparing raw contours from each flightline against adjoining flightlines at specific points. The final test is the vertical LIDAR control report.
.7 meter
This value is an estimation
Survey control points were used to validate the accuracy of the LIDAR surface model after automatic and hand filtering. This surface exceeds the NSSDA vertical accuracy specifications of .15 meters..
0.07 meters preliminary
This value is measured as RMSEz.
Merrick & Company
20071201
Ground Control
spreadsheet
Aurora, CO
Merrick & Company
disc
20071003
unknown
20080131
unknown
ground condition
GROUND_CONTROL
GPS control network for LIDAR acquisition and processing.
Merrick & Company
20071201
LIDAR
point digital data
Aurora, CO
Merrick & Company
disc
20071003
unknown
20080131
unknown
ground condition
LIDAR
LIDAR points form the basis of the DTM surface.
LIDAR data was collected using Merrick's ALS50 Phase 2 sensor. The raw data was verified in MARS software for complete coverage of the project area, and boresighted to align the flightlines. Raw data files were parsed into manageable client-specific tiles. These tiles were then processed through automated filtering that separates the data into different classification groups: unclassified points, ground points, low points and water. The data was next taken into MARS to reclassify the erroneous points that may remain in the LIDAR point cloud after auto filter.
LIDAR
GROUND_CONTROL
20071210
Doug Jacoby
Merrick & Company
Director of Projects / Project Manager
mailing and physical address
2450 South Peoria Street
Aurora
CO
80014
U.S.A.
303-353-3903
303-745-0964
doug.jacoby@merrick.com
8 am - 5 pm, Mountain Time Zone, Monday thru Friday
Call or email during business hours
0%
Point
Universal Transverse Mercator
14
0.999600
-99.000000
0.000000
500000.000000
0.000000
row and column
.001
.001
meters
D_WGS_1984
WGS_1984
6378137.000000
298.257224
North American Vertical Datum of 1988
0.001
meters
Implicit coordinate
LAS
Las Data
Merrick
Attributes inclued in the LAS file include:
x-coord in meters (double) precision .001
y-coord in meters (double) precision .001
elevation in meters (double) precision .001
classification (interger) 1 = Unclassified, 2 = Ground, 7 = Low Points, 9 = Water
Intensity (interger) range 0 -255
Valid
USGS National Center for Earth Resources Observation & Science (EROS)
mailing and physical address
Customer Services, USGS National Center for Earth Resources Observation & Science (EROS)
Sioux Falls
South Dakota
57198-0001
+001 605-594-6151
1-800-252-4547
+001 605-594-6933
+001 605-594-6589
custserv@usgs.gov
0800 - 1600 CT, M-F, -6 h GMT
none
Downloadable Data
Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made by the USGS regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. The USGS will warrant the delivery of this product in computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer input peripherals or when the physical medium is delivered in damaged condition. Requests for adjustment of credit must be made within 90 days from the date of this shipment from the ordering site.
20080417
Roger Hanson
Merrick & Company
Director of Operations
mailing and physical address
2450 South Peoria Street
Aurora
CO
80014
U.S.A.
303-353-3878
303-751-0741
303-745-0964
roger.hanson@merrick.com
8 am - 5 pm, Mountain Time Zone, Monday thru Friday
Call or email during business hours
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
Unknown
Unknown
Unknown
Unknown
Unknown
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile