Dekalb County, GA Lidar Derived DTM and TIN 2010

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Atlanta Regional Commission (ARC)
Publication_Date: 2010
Title: Dekalb County, GA Lidar Derived DTM and TIN 2010
Edition: 1.0
Geospatial_Data_Presentation_Form: Point and vector digital data
Publication_Information:
Publication_Place: Decatur, GA
Publisher: Dekalb County, GA
Description:
Abstract:
This metadata record describes the DTM comprised of classified aerial lidar elevation points, photogrammetrically compiled breaklines and the derived TIN for Dekalb County, GA
Purpose:
The lidar DEM data was collected for the Dekalb County, GA area. All lidar returns were classified using the default classes of Terrascan processing software for Unclassified Points (class 1), Ground points (class 2), Water points (class 9), Overlap points (class 12). The lidar ground points are supplemented with photogrammmetrically compiled breaklines from digital imagery collected during the same project time frame as the lidar. The ground class points, often refered to as "bald earth" are then used as an input to proprietary and publicly available processing software to generate a Triangulated Irregular Network (TIN) model. Classified lidar DEMs and derived TIN models are useful for a variety of applications, such as aiding in contour generation, development of digital surface models, 3D modeling, flood plane mapping, viewshed analysis and the production of orthophotos.
Time_Period_of_Content:
Time_Period_Information:
Multiple_Dates/Times:
Single_Date/Time:
Calendar_Date: 20100102
Single_Date/Time:
Calendar_Date: 20100103
Currentness_Reference: Ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: Unknown
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -84.35091417
East_Bounding_Coordinate: -84.02334971
North_Bounding_Coordinate: 33.97061816
South_Bounding_Coordinate: 33.61447836
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Digital terrain model
Theme_Keyword: DTM
Theme_Keyword: LiDAR
Theme_Keyword: mapping
Theme_Keyword: "bare earth"
Theme_Keyword: mass points
Theme_Keyword: topography
Theme_Keyword: Triangulated Irregular Network
Theme_Keyword: TIN
Place:
Place_Keyword_Thesaurus: Dekalb County
Place_Keyword: Dekalb County
Place_Keyword: Decatur
Place_Keyword: Dunwoody
Place_Keyword: Doraville
Place_Keyword: Chamblee
Place_Keyword: Pine Lake
Place_Keyword: Clarkston
Place_Keyword: Avondale
Place_Keyword: Stone Mountain
Place_Keyword: Tucker
Place_Keyword: Atlanta
Place_Keyword: Belvedere Park
Place_Keyword: Panthersville
Place_Keyword: Lithonia
Place_Keyword: Georgia
Access_Constraints: Unknown
Use_Constraints: Unknown
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Stacy Grear
Contact_Organization: Dekalb County GIS Department
Contact_Position: Acting Director
Contact_Address:
Address_Type: Mailing and physical address
Address: 1300 Commerce Drive, Suite 600
City: Decatur
State_or_Province: GA
Postal_Code: 30030
Country: U.S.A.
Contact_Voice_Telephone: 404-371-3619
Contact_Facsimile_Telephone: 404-371-3211
Contact_Electronic_Mail_Address:
scgrear@co.dekalb.ga.us will change to scgrear@dekalbcountyga.gov on July 1, 2010
Hours_of_Service: 8:30 - 5:00 pm
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Attribute accuracy is tested in the LiDAR processing stage. After classification of the LiDAR data, the 'bald earth' point class is compared to ground control collected within the project area.
Logical_Consistency_Report:
LiDAR data is collected within the project area, processed and verified against control.
Completeness_Report:
LiDAR data is collected for the project area. Post processing of the simultaneously acquired GPS/INS is performed and applied to the laser returns to output a point cloud in the specified project coordinate system and datums. The point cloud data is then subjected to automated classification routines to assign all points in the point cloud to ground, water, overlap and unclassified point classes. Anomalous laser returns that occur infrequently are removed entirely from the data set. The ground class points are then compared to surveyed ground control to develop an accuracy measure of the laser terrain data.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Horizontal positional accuracy for LiDAR is dependent upon the quality of the GPS/INS solution, sensor calibration and ground conditions at the time of data capture. The standard system results for horizontal accuracy are less than 1 meter.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 1
Horizontal_Positional_Accuracy_Explanation:
This value is computed by comparing ground control to an intensity based image derived from the classified LiDAR data and represents the RMSE of residuals on controls within the project area.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Vertical positional accuracy for LiDAR is dependent upon the quality of the GPS/INS solution, sensor calibration and ground conditions at the time of data capture. The vertical accuracy for this project was tested with a resultant RMSE of 0.057 meter (0.188 feet).
Quantitative_Vertical_Positional_Accuracy_Assessment:
Vertical_Positional_Accuracy_Value: 0.057
Vertical_Positional_Accuracy_Explanation:
This value is computed by comparing ground control elevation to the classified LiDAR ground surface and represents the RMSE of residuals on controls within the project area. Units = meters.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Kucera International Inc.
Publication_Date: Unpublished material
Title: LiDAR Data
Edition: 1.0
Geospatial_Data_Presentation_Form: Remote sensing image
Publication_Information:
Publication_Place: None
Publisher: None
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Multiple_Dates/Times:
Single_Date/Time:
Calendar_Date: 20100102
Single_Date/Time:
Calendar_Date: 20100103
Source_Currentness_Reference: Ground condition
Source_Citation_Abbreviation: LIDAR
Source_Contribution:
Aerial LiDAR and GPS/IMU data was recorded for the defined project area.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Kucera International Inc.
Publication_Date: Unpublished material
Title: Aerial Digital Imagery
Edition: 1.0
Geospatial_Data_Presentation_Form: Remote sensing image
Publication_Information:
Publication_Place: None
Publisher: None
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Multiple_Dates/Times:
Single_Date/Time:
Calendar_Date: 20100218
Single_Date/Time:
Calendar_Date: 20100219
Single_Date/Time:
Calendar_Date: 20100220
Single_Date/Time:
Calendar_Date: 20100221
Source_Currentness_Reference: Ground condition
Source_Citation_Abbreviation: IMG
Source_Contribution:
New digital aerial imagery and GPS/IMU data was recorded for the defined project area.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Kucera International, Inc.
Publication_Date: 2010
Title: Ground control
Edition: 1.0
Geospatial_Data_Presentation_Form: tabular digital data
Publication_Information:
Publication_Place: None
Publisher: None
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2010
Source_Currentness_Reference: Ground condition
Source_Citation_Abbreviation: CONT
Source_Contribution:
Targeted ground control is used to create a digital control file and control report as well as QC check of LiDAR accuracy. Predefined points (NGS when available) within the project area are targeted.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Kucera International, Inc.
Publication_Date: 2010
Title: Triangulated Irregular Network
Edition: 1.0
Geospatial_Data_Presentation_Form: Vector digital data
Publication_Information:
Publication_Place: None
Publisher: None
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2010
Source_Currentness_Reference: Ground condition
Source_Citation_Abbreviation: TIN
Source_Contribution:
Using the lidar elevation points and compiled breaklines as inputs, a Triangulated Irregular Network (TIN) is generated using ESRI ArcGIS software.
Process_Step:
Process_Description:
At selected locations throughout the site, accurate GPS coordinates and elevations are surveyed and the points are marked with targets.
Source_Used_Citation_Abbreviation: None
Process_Date: 2010
Source_Produced_Citation_Abbreviation: CONT
Process_Step:
Process_Description:
New LiDAR data is captured for the project area using a Leica ALS60 LiDAR instrument in conjunction with a POSAV Applanix GPS/INS system mounted within a Piper Navajo twin engine airplane.
Source_Used_Citation_Abbreviation: None
Process_Date: 2010
Source_Produced_Citation_Abbreviation: LIDAR, GPS_RAW
Process_Step:
Process_Description:
New aerial digital imagery with airborne GPS/IMU data is acquired for the project area.
Source_Used_Citation_Abbreviation: None
Process_Date: 2010
Source_Produced_Citation_Abbreviation: IMG
Process_Step:
Process_Description:
The airborne GPS data is processed in Terratec TerraPos software and then combined with the IMU data in Applanix PosPAC software to determine the LiDAR sensor's angle and orientation in the terrain (project) coordinate system and datums during the survey. The same GPS/IMU processing is performed for the digital imagery to define the orientation parameters of the images to be used in stereo compilation of terrain breaklines.
Source_Used_Citation_Abbreviation: GPS_RAW
Process_Date: 2010
Source_Produced_Citation_Abbreviation: GPS_SOL
Process_Step:
Process_Description:
LiDAR data is processed using the GPS/INS solution. Data is classified to produce: Class 1: unclassified points Class 2: ground points Class 9: water points Class 12: overlap points
Source_Used_Citation_Abbreviation: CONT, GPS_SOL, LIDAR
Process_Date: 2010
Source_Produced_Citation_Abbreviation: LAS
Process_Step:
Process_Description:
The ground class of the processed lidar data is then compared to the ground control and elevation differences between the lidar surface and surveyed elevation are recorded in tabular form. Vertical accuracy statistices are then developed to produce vertical RMSE and overall accuracy estimates and reports.
Source_Used_Citation_Abbreviation: CONT, LIDAR
Process_Date: 2010
Source_Produced_Citation_Abbreviation: None
Process_Step:
Process_Description:
Photogrammetrically compiled breaklines are compiled to supplement the lidar ground points.
Source_Used_Citation_Abbreviation: IMG
Process_Date: 2010
Source_Produced_Citation_Abbreviation: BREAK
Process_Step:
Process_Description:
Water polygons are buffered to remove any lidar points within the polygon to flatten these surfaces.
Source_Used_Citation_Abbreviation: BREAK, LIDAR
Process_Date: 2010
Source_Produced_Citation_Abbreviation: DTM1
Process_Step:
Process_Description:
Breaklines are buffered to remove lidar surface points on or near the breakline.
Source_Used_Citation_Abbreviation: LIDAR, BREAK
Process_Date: 2010
Source_Produced_Citation_Abbreviation: DTM2
Process_Step:
Process_Description:
The Traingulated Irregular Network is generate with ESRI ArcGIS software.
Source_Used_Citation_Abbreviation: DTM2
Process_Date: 2010
Source_Produced_Citation_Abbreviation: TIN
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Ring composed of chains
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Node, planar graph
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Link
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: State Plane Coordinate System 1983
State_Plane_Coordinate_System:
SPCS_Zone_Identifier: 1002
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999900
Longitude_of_Central_Meridian: -84.166667
Latitude_of_Projection_Origin: 30.000000
False_Easting: 2296583.333333
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.5
Ordinate_Resolution: 0.5
Planar_Distance_Units: U.S. Survey Foot
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983/86
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.25722210088
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: North American Vertical Datum of 1988
Altitude_Resolution: 0.1
Altitude_Distance_Units: U.S. Survey Foot
Altitude_Encoding_Method: Implicit coordinate
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Stacy Grear
Contact_Organization: Dekalb County GIS Department
Contact_Position: Acting Director
Contact_Address:
Address_Type: Mailing and physical address
Address: 1300 Commerce Drive, Suite 600
City: Decatur
State_or_Province: GA
Postal_Code: 30030
Country: U.S.A.
Contact_Voice_Telephone: 404-371-3619
Contact_Facsimile_Telephone: 404-371-3211
Contact_Electronic_Mail_Address:
scgrear@co.dekalb.ga.us will change to scgrear@dekalbcountyga.gov on July 1, 2010
Hours_of_Service: 8:30 - 5:00 pm
Resource_Description: Dekalb County, GA Lidar Derived DEM and TIN 2010
Distribution_Liability:
Dekalb County provides the geographic data "as is". This organization makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. Also, this organization makes no warranty, either expressed or implied, regarding the condition of the product or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these files have been processed successfully on computers at this organization, no warranty is made by this organization regarding the use of these data on any other system, nor does the fact of distribution constitute or imply such a warranty.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: TIFF (.tif) ESRI TIN
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: Contact Dekalb County GIS Department
Access_Instructions: Contact Dekalb County GIS Department
Offline_Option:
Offline_Media: CD-ROM, DVD
Recording_Format: ISO 9660
Fees: Contact Dekalb County GIS Department
Ordering_Instructions: Contact Dekalb County GIS Department
Available_Time_Period:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2010
Metadata_Reference_Information:
Metadata_Date: 2010
Metadata_Review_Date: 2010
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Stacy Grear
Contact_Organization: Dekalb County GIS Department
Contact_Position: Acting Director
Contact_Address:
Address_Type: Mailing and physical address
Address: 1300 Commerce Drive, Suite 600
City: Decatur
State_or_Province: GA
Postal_Code: 30030
Country: U.S.A.
Contact_Voice_Telephone: 404-371-3619
Contact_Facsimile_Telephone: 404-371-3211
Contact_Electronic_Mail_Address:
scgrear@co.dekalb.ga.us will change to scgrear@dekalbcountyga.gov on July 1, 2010
Hours_of_Service: 8:30 - 5:00 pm
Metadata_Standard_Name: FGDC CSDGM
Metadata_Standard_Version: FGDC-STD-001-1998
Generated by mp version 2.9.1 on Thu Dec 16 15:08:43 2010