The Iowa LiDAR Project - LAS and ASCII Files

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Iowa LiDAR Consortium
Title: The Iowa LiDAR Project - LAS and ASCII Files
Publication_Information:
Publisher: Iowa Lidar Consortium
Description:
Abstract:
This is collection level metadata for LAS and ASCII data files from the statewide Iowa Lidar Project. The Iowa Light Detection and Ranging (LiDAR) Project collects location and elevation (X, Y, Z) data to a set standard for the entire state of Iowa.
LIDAR is defined as an airborne laser system, flown aboard rotary or fixed-wing aircraft, that is used to acquire x, y, and z coordinates of terrain and terrain features that are both manmade and naturally occurring. LIDAR systems consist of a light-emitting scanning laser, an airborne Global Positioning System (GPS) with attendant GPS base station(s), and an Inertial Measuring Unit (IMU).
The laser scanning system measures ranges from the scanning laser to terrain surfaces by measuring the time it takes for the emitted light (LIDAR return) to reach the earth's surface and reflect back to the onboard LIDAR detector.
The airborne GPS system ascertains the in-flight three-dimensional position of the sensor, and the IMU delivers precise information about the attitude of the sensor. The LIDAR system incorporates data from these three subsystems to produce a large cloud of points on the land surface whose X, Y, and Z coordinates are known within the specified accuracy.
This collection consists of ASCII files of bare earth elevations and intensity (x,y,z,i) and, LAS (version 1.0 lidar data interchange standard) binary files that include all 1st and last returns, intensity and bare earth classification.
Purpose:
This digital, geographically referenced data set was developed by the Iowa Department of Natural Resources to carry out agency responsibilities related to management, protection, and development of Iowa's natural resources.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 2007
Ending_Date: ongoing
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -96.684901
East_Bounding_Coordinate: -90.069432
North_Bounding_Coordinate: 43.557019
South_Bounding_Coordinate: 40.332776
Keywords:
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: elevation
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: LiDAR
Theme_Keyword: Light Detection and Ranging
Theme_Keyword: elevation
Theme_Keyword: LAS file
Theme_Keyword: ASCII file
Place:
Place_Keyword_Thesaurus: GNIS
Place_Keyword: Iowa
Access_Constraints: None
Use_Constraints:
The development of the coverages in the NRGIS Library represents a major investment of staff time and effort. As a professional responsibility, the Iowa DNR expects to receive proper credit when these GIS coverages are utilized. he Department also expects that the original documentation will remain with any redistribution of these coverages.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Chris Ensminger
Contact_Organization: Iowa Department of Natural Resources
Contact_Address:
Address_Type: mailing and physical address
Address: 502 East 9th
City: Des Moines
State_or_Province: IA
Postal_Code: 50319
Contact_Voice_Telephone: 515.281.4216
Contact_Electronic_Mail_Address: chris.ensminger@dnr.iowa.gov
Data_Set_Credit:
The Iowa Lidar Consortium consists of the Iowa Department of Agriculture and Land Stewardship, Iowa Department of Natural Resources, Iowa Department of Transportation, the USDA Natural Resources Conservation Service (NRCS), and the US Geological Survey (USGS).
Security_Information:
Security_Classification_System: State of Iowa Enterprise Data Classification Standard
Security_Classification: Public

Data_Quality_Information:
Logical_Consistency_Report: None
Completeness_Report:
Data will continue to be collected until a complete set is obtained. See the Cross-referece citations for files that track the completeness of the project.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
LiDAR data are currently undergoing quality assurance testing by the U.S. Geological Survey (USGS). While this testing is underway, these data are being provided as-is, with no guarantee of accuracy. If USGS testing indicates data do not meet accuracy specs, those data will immediately be removed from distribution. Until USGS certification is received, users should verify data accuracies for themselves.
Standard LiDAR Specifications: -Sanborn prepares flight plans as parallel flight lines with at least one cross flight line to assure positional accuracy and quality control. -Sanborn uses only automated filtering for Standard LiDAR products with the following minimum performance for bare earth elevation models: -89% of artifacts or more removed depending on terrain and vegetation -90% of all outliers removed -90% of all vegetation removed -93% of all buildings removed
-1.4 meter average point spacing -Scan frequency and angles based on project area terrain and landcover
-1 meter RMSE -No independent field verification


FEMA Compliant LiDAR Specifications: -Sanborn flight plans are parallel flight lines with at least one cross flight line to assure positional accuracy and quality control, and collection verified with both kinematic and static collections. -Sanborn uses automated and manual filtering for LiDAR products with the following minimum performance for bare earth elevation models: -90% of artifacts or more removed depending on terrain and vegetation -95% or better of all outliers removed -95% of all vegetation removed -98% of all buildings removed
In addition to Standard LiDAR specifications: -Sanborn field verification -3 classes, 20 pts. each
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Standard LiDAR Specifications: +/- 18 cm
Bare Earth: 18.5 cm RMSE Vegetation: 37 cm RMSE
Lineage:
Process_Step:
Process_Description:
Data Collection: Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, flight lines of standard density (1.4 meter ground sample distance) data were collected over areas in Iowa. Multiple returns were recorded for each laser pulse along with an intensity value for each return. During the LIDAR campaign, the Sanborn field crew conducted a GPS field survey to establish final coordinates of the ground base stations for final processing of the base-remote GPS solutions.
Process_Date: Unknown
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jamie Young
Contact_Organization: Sanborn Map Company, Inc.
Contact_Position: LiDAR Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1935 Jamboree Drive #100
City: Colorado Springs
State_or_Province: CO
Postal_Code: 80920
Contact_Voice_Telephone: 719.264.5602
Contact_Facsimile_Telephone: 719.264.5637
Contact_Electronic_Mail_Address: jyoung@sanborn.com
Process_Step:
Process_Description:
Airborne GPS Processing: Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line. The overlap between flight lines was removed to provide a homogeneous coverage, and the coverage was classified to extract a bare earth digital elevation model (DEM).
Airborne GPS is differentially processed using the GrafNAV V7.50 software by Waypoint Consulting of Calgary, Alberta, Canada. The PDOP and distance separation is as follows:
IMU data is processed using the PosPac V4.2 software by Applanix Corporation of Richmond Hill, Ontario, Canada.
The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta, Georgia.
The classification and quality control (QC) of LiDAR data is carried out using TerraScan software by Terrasolid Limited of Helinski, Finland.
Process_Date: Unknown
Process_Step:
Process_Description:
IMU data Processing: IMU data provides information concerning roll, pitch and yaw of collection platform during collection event. IMU information allows the pulse vector to be properly placed in 3D space allowing the distance from the aircraft reference point to be properly positioned on the elevation model surface. IMU data is processed using the PosPac V4.2 software by Applanix Corporation of Richmond Hill, Ontario, Canada.
Process_Date: Unknown
Process_Step:
Process_Description:
LIDAR Point Classification The classification and quality control (QC) of LiDAR data is carried out using TerraScan software by Terrasolid Limited of Helinski, Finland.
Process_Date: Unknown
Process_Step:
Process_Description:
Output LAS Files and ASCII The product output of LiDAR data is carried out using TerraScan software by Terrasolid Limited of Helinski, Finland.
Process_Date: Unknown

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 15
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999600
Longitude_of_Central_Meridian: -93.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 500000.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.001024
Ordinate_Resolution: 0.001024
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: North American Vertical Datum of 1988
Altitude_Distance_Units: meters
Altitude_Encoding_Method:
Explicit elevation coordinate included with horizontal coordinates

Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: University of Northern Iowa, GeoTREE Center
Resource_Description: Downloadable Data
Distribution_Liability:
All data available on this site are currently undergoing quality assurance testing by the U.S. Geological Survey (USGS). While this testing is underway, this data are being provided as-is, with no guarantee of accuracy. If USGS testing indicates data do not meet accuracy specs, those data will immediately be removed from this site. Until USGS certification is received, users should verify data accuracies for themselves.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ASCII and LAS files
File_Decompression_Technique: 7zip
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <http://geotree2.geog.uni.edu/lidar/>
Fees: None
Turnaround: Immediate

Metadata_Reference_Information:
Metadata_Date: 20090129
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Iowa Geological Survey, DNR
Contact_Person: GIS Librarian
Contact_Address:
Address_Type: Mailing and Physical
Address: 109 Trowbridge Hall
City: Iowa City
State_or_Province: IA
Postal_Code: 52242-1319
Contact_Voice_Telephone: 319-335-1575
Contact_Electronic_Mail_Address: gis_library@igsb.uiowa.edu
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile

Generated by mp version 2.9.6 on Thu Jan 29 10:39:54 2009