Taylor Creek Area lidar-derived DEM

Metadata also available as

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: St. Johns River Water Management District
Publication_Date: 20100909
Publication_Time: Unknown
Title: Taylor Creek Area lidar-derived DEM
Geospatial_Data_Presentation_Form: SDE raster digital data
Online_Linkage:
Server=earth; Service=esri_sde; User=gislib; Version=SDE.DEFAULT
Description:
Abstract:
The SJRMWD Taylor Creek Reservoir Project covers 48 square miles in Orange and Osceola Counties in Florida. Dewberry produced one hydro flattened DEM that covers the entire project area. The hydro flattened DEMs were created with a 2.5 ft cell size and are created from the class 2, ground, LiDAR points and 3D breaklines that were collected to project specifications. The DEM format is an Arc GRID.
Purpose:
The hydro flattened Digital Elevation Model (DEM) provides a bare earth elevation surface that depicts the ground surface with flattened inland water features.
Supplemental_Information:
A complete description of this dataset is available in the Minimum Technical Standard ( MTS report) submited to St. Johns River Water Management District.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20100216
Ending_Date: 20100219
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -81.019180
East_Bounding_Coordinate: -80.910321
North_Bounding_Coordinate: 28.391386
South_Bounding_Coordinate: 28.267587
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: DTM
Theme_Keyword: Elevation
Theme_Keyword: Lidar
Theme_Keyword: LAS
Theme_Keyword: DEM
Theme_Keyword: Hydro Flattened
Theme_Keyword: Breaklines
Place:
Place_Keyword_Thesaurus: SJRWMD-GIS Metadata Thesaurus
Place_Keyword: Florida
Place_Keyword: St. Johns River Water Management District
Place_Keyword: Orange County
Place_Keyword: Osceola County
Place_Keyword: Taylor Creek Reservoir
Access_Constraints: None
Use_Constraints:
The St. Johns River Water Management District prepares and uses information for its own purposes and this information may not be suitable for other purposes. This information is provided "as is". Further documentation of this data can be obtained by contacting: St. Johns River Water Management District, Division of Integrated Application Systems, Post Office Box 1429, Palatka, Florida, 32178-1429, (386) 329-4500.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: St. Johns River Water Management District
Contact_Position: GIS Data Manager, Information Resources Department
Contact_Address:
Address_Type: mailing and physical address
Address: 4049 Reid Street
City: Palatka
State_or_Province: FL
Postal_Code: 32177
Country: USA
Contact_Voice_Telephone: (386) 329-4500
Contact_Electronic_Mail_Address: gis_support@sjrwmd.comv
Hours_of_Service: 0800 - 1700 ET
Native_Data_Set_Environment:
Microsoft Windows Vista Version 6.1 (Build 7600) ; ESRI ArcCatalog 9.3.1.1850
Data_Quality_Information:
Logical_Consistency_Report: Data covers the tile scheme provided for the project area.
Completeness_Report:
A visual qualitative assessment was performed to ensure data completeness and full tiles. No void or missing data exists.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The DEMs are derived from the source LiDAR and 3D breaklines created from the LiDAR. LiDAR source compiled to meet 3.5 foot horizontal accuracy.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 3.5 feet
Horizontal_Positional_Accuracy_Explanation:
The DEMs are derived from the source LiDAR and 3D breaklines created from the LiDAR. Horizontal accuracy is not performed on the DEMs, breaklines, or LiDAR. LiDAR vendors perform calibrations on the LiDAR sensor and compare data to adjoing flight lines to ensure LiDAR meets the 3.5 ft horizontal accuracy standard at the 95% confidence level. Please see Appendix D, the LiDAR Processing Report, of the MTS Report for more details.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The DEMs are derived from the source LiDAR and 3D breaklines created from the LiDAR. Vertical accuracy is not tested on the DEMs.
Quantitative_Vertical_Positional_Accuracy_Assessment:
Vertical_Positional_Accuracy_Value: 0.29 feet
Vertical_Positional_Accuracy_Explanation:
The DEMs are derived from the source LiDAR and 3D breaklines created from the LiDAR. Vertical accuracy is not tested on the DEMs.
Based on the vertical accuracy testing conducted by Dewberry, using NSSDA and FEMA methodology, vertical accuracy at the 95% confidence level (called Accuracyz) is computed by the formula RMSEz x 1.9600. The dataset for Taylor Creek Reservoir satisfies the criteria: Lidar dataset tested 0.29 ft vertical accuracy at 95% confidence level in open terrain, based on open terrain RMSEz (0.15 ft) x 1.9600. Lidar dataset tested 0.33 ft vertical accuracy at 95% confidence level in all land cover categories combined, based on consolidated RMSEz (0.17 ft) x 1.9600.
Based on the vertical accuracy testing conducted by Dewberry, using NDEP and ASPRS methodology, consolidated vertical accuracy at the 95% confidence level is computed using the 95th percentile method. The dataset for St. Johns River Water Management District satisfies the criteria: Lidar dataset tested 0.30 ft vertical accuracy at 95% confidence level in all land cover categories combined.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Terrapoint USA
Publication_Date: 201002
Publication_Time: Unknown
Title: Lidar
Geospatial_Data_Presentation_Form: map
Other_Citation_Details:
LiDAR Survey of Taylor Creek Reservoir contracted by St. Johns River Water Management District (SJRWMD), conducted from 2/16/10 to 2/19/10.
Type_of_Source_Media: online
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20100216
Ending_Date: 20100219
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: Lidar
Source_Contribution:
Ground LiDAR data was used in conjunction with 3D breaklines to create the bare earth Digital Elevation Model for Taylor Creek Reservoir.
Process_Step:
Process_Description:
Terrapoint used their latest helicopter-based LiDAR sensor. The Riegl LMS-Q560 helicopter-mounted system is designed specifically for small block sites and corridor applications.
A combination of Sokkia GSR 2600 and NovAtel DL-4+ dual-frequency GPS receivers were used to support the airborne operations of this survey and to establish the GPS control network.
Airborne GPS kinematic data was processed on-site using GrafNav kinematic On-The-Fly (OTF) software. Flights were flown with a minimum of 6 satellites in view (13o above the horizon) and with a PDOP of better than 4. Distances from base station to aircraft were kept to a maximum of 24km. For all flights, the GPS data can be classified as excellent, with GPS residuals of 3cm average or better but no larger than 10cm being recorded.
The initial step of calibration is to verify availability and status of all needed GPS and Laser data against field notes and compile any data if not complete. Laser data points are generated using Terrapoint's proprietary laser post-processing software. This software combines the raw laser range and angle data file with the finalized GPS/IMU information. The resulting point cloud has been projected into the desired coordinate system in LAS binary format. All missions are validated against the adjoining missions for relative vertical biases and collected GPS kinematic ground truthing points for absolute vertical accuracy purposes. On a project level, a coverage check is carried out to ensure no slivers are present in areas where it was possible to acquire LiDAR at a safe AGL.
Source_Used_Citation_Abbreviation: Airborne Global Positioning System Data
Source_Used_Citation_Abbreviation: Inertial Measurement Unit
Process_Date: 201002
Source_Produced_Citation_Abbreviation: LiDAR Point Cloud LAS 1.2 format
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Terrapoint USA
Contact_Address:
Address_Type: mailing and physical address
Address: 251216 Grogan's Park Drive
City: The Woodlands
State_or_Province: Texas
Postal_Code: 77380
Country: USA
Contact_Voice_Telephone: 1-877-999-7687
Contact_Facsimile_Telephone: 1-281-296-0869
Hours_of_Service: Monday to Friday, 8 - 5, CST
Process_Step:
Process_Description:
The data is classified by using a proprietary routine in the software Terrascan. The routine removes any obvious outliers from the dataset and then extracts the initial ground layer. The ground extraction process encompassed in this routine takes place by building an iterative surface model. This surface model is generated using three main parameters: building size, iteration angle and iteration distance. The initial model is based on low points being selected by a "roaming window" with the assumption is that these are the ground points. The size of this roaming window is determined by the building size parameter. The low points are triangulated and the remaining points are evaluated and subsequently added to the model if they meet the iteration angle and distance constraints. This process is repeated until no additional points are added within an iteration. A second critical parameter is the maximum terrain angle constraint, which determines the maximum terrain angle allowed within the classification model. The data is then manually quality controlled with the use of hillshading, cross-sections and profiles. Any points found to be of class vegetation, building or error during the quality control process, are removed from the ground model and placed on the appropriate layer. An integrity check is also performed simultaneously to verify that ground features such as rock cuts, elevated roads and crests are present. Once data has been cleaned and complete, it is then reviewed by a supervisor via manual inspection and through the use of a hillshade mosaic of the entire project area.
Source_Used_Citation_Abbreviation: LiDAR Point Cloud LAS 1.1 format
Process_Date: 201002
Source_Produced_Citation_Abbreviation: LiDAR datasets with initial ground classification
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Terrapoint USA
Contact_Address:
Address_Type: mailing and physical address
Address: 251216 Grogan's Park Drive
City: The Woodlands
State_or_Province: Texas
Postal_Code: 77380
Country: USA
Contact_Voice_Telephone: 1-877-999-7687
Contact_Facsimile_Telephone: 1-281-296-0869
Hours_of_Service: Monday to Friday, 8 - 5, CST
Process_Step:
Process_Description:
After receiving the LAS tiles with the initial ground classification from Terrapoint, Dewberry performed the final classification and editing on the LiDAR dataset. Dewberry utilizes a variety of software suites for inventory management, and data processing. The LAS dataset was received and imported into GeoCue task management software and retiled into 2,500 ft by 2,500 ft tiles for processing in Terrascan. Each tile was imported into Terrascan and a surface model was created to examine the ground classification. Dewberry analysts visually reviewed the ground surface model and corrected errors in the ground classification such as vegetation, buildings, and bridges that were present following the initial processing conducted by Terrapoint. Dewberry analysts employ 3D visualization techniques to view the point cloud at multiple angles and in profile to ensure that non-ground points are removed from the ground classification. After the ground classification corrections were completed, the dataset was processed through a water classification routine that utilizes breaklines compiled by Dewberry to automatically classify hydro features. The water classification routine selects points within the breakline polygons and automatically classifies them as class 9, water. The fully classified dataset is then processed through Dewberry's comprehensive quality control program. Once the dataset has been approved, Dewberry uses GeoCue to retile the data back to the original 5,000 ft by 5,000 ft tile scheme as dictated in the project specifications.
The data was classified as follows: Class 1 = Unclassified. This class includes vegetation, buildings, noise etc. Class 2 = Ground Class 7= Noise Class 9 = Water Class 12= Overlap
The LAS header information was verified to contain the following: Class (Integer) GPS Week Time (0.0001 seconds) Easting (0.01 foot) Northing (0.01 foot) Elevation (0.01 foot) Echo Number (Integer 1 to 4) Echo (Integer 1 to 4) Intensity (8 bit integer) Flight Line (Integer) Scan Angle (Integer degree)
Source_Used_Citation_Abbreviation: LiDAR datasets with initial ground classification
Process_Date: 201002
Source_Produced_Citation_Abbreviation: Final LiDAR datasets with ASPRS classifications
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Keith Patterson
Contact_Organization: Dewberry - Geospatial Services Group
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1000 N. Ashley Drive, Suite 801
City: Tampa
State_or_Province: FL
Postal_Code: 33602
Country: USA
Contact_Voice_Telephone: 813.225.1325
Contact_Facsimile_Telephone: 813.225.1385
Contact_Electronic_Mail_Address: kpatterson@dewberry.com
Hours_of_Service: 8:00 - 5:00 EST
Process_Step:
Process_Description:
Dewberry used GeoCue software to develop LiDAR stereo models of the Taylor Creek Reservoir Project area so the LiDAR derived data could be viewed in 3-D stereo using Socet Set softcopy photogrammetric software. Using LiDARgrammetry procedures with LiDAR intensity imagery, Dewberry stereo-compiled the five types of hard breaklines in accordance with the Data Dictionary at Appendix C.
All drainage breaklines are monotonically enforced to show downhill flow. Water bodies are collected in stereo and the lowest elevation is applied to the entire waterbody.
Low Confidence Polygons represent areas where the ground is obscured by dense vegetation to the extent that the generated contours from the LiDAR surface may not meet accuracy specifications. These areas of low confidence are created from a multistep process. First, density grids are created from the LAS files for each LAS tile, using ground points only. These density grids visually display the data in two colors-red for sparse areas and green for dense areas according to the point density specifications the user defines. For the Taylor Creek Reservoir Project, the point density tolerance was set to 1 foot. This means that areas 1 sq. ft in size or greater that did not contain at least one ground point would display as red. These density grids are exported to a raster format, isolating the sparse or red areas. The rasters are exported to polygons and these polygons represent the areas of sparse LiDAR ground penetration visible in the LAS density grids. All polygons less than one-half acre in size are removed from the dataset. The polygon layer is then verified against breaklines to remove polygons representing water bodies and hydrographic features. Next, the polygon layer is verified against imagery to remove polygons representing buildings or any other features that would cause valid voids in the ground point data. Lastly, the reviewed polygon layer is simplified to remove the sharp, jagged edges that are a result of the processing.
All breaklines conform to the data format requirements outlined by the projects Data Dictionary contained within Appendix C.
Source_Used_Citation_Abbreviation: Final LiDAR datasets with ASPRS classifications
Process_Date: 201002
Source_Produced_Citation_Abbreviation: 3D breaklines in ESRI file geodatabase format
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Keith Patterson
Contact_Organization: Dewberry - Geospatial Services Group
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1000 N. Ashley Drive, Suite 801
City: Tampa
State_or_Province: FL
Postal_Code: 33602
Country: USA
Contact_Voice_Telephone: 813.225.1325
Contact_Facsimile_Telephone: 813.225.1385
Contact_Electronic_Mail_Address: kpatterson@dewberry.com
Hours_of_Service: 8:00 - 5:00 EST
Process_Step:
Process_Description:
An ESRI Terrain is generated from the inputs listed below. The surface type of each input is also listed.
Masspoints (ground points exported from LiDAR): masspoints HYDROGRAPHICFEATURE: hard line ISLAND: hard line ROADBREAKLINE: hard line WATERBODY: hard replace
Source_Used_Citation_Abbreviation: Lidar Ground Points, Class 2
Source_Used_Citation_Abbreviation: 3D Breaklines
Process_Date: 201008
Source_Produced_Citation_Abbreviation: ESRI Terrain
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Keith Patterson
Contact_Organization: Dewberry - Geospatial Services Group
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1000 N. Ashley Drive, Suite 801
City: Tampa
State_or_Province: FL
Postal_Code: 33602
Country: USA
Contact_Voice_Telephone: 813.225.1325
Contact_Facsimile_Telephone: 813.225.1385
Contact_Electronic_Mail_Address: kpatterson@dewberry.com
Hours_of_Service: 8:00 - 5:00 EST
Process_Step:
Process_Description:
The ESRI Terrain is converted to raster. The raster is created to the boundary of the project area. The raster was created with a 2.5 foot cell size and in ESRI Arc GRID format. The raster is verified to have the correct number of pixel rows and columns and that the pixels align to the tile grid properly.
Source_Used_Citation_Abbreviation: ESRI Terrain
Process_Date: 201008
Source_Produced_Citation_Abbreviation: One project hydro flattened DEM
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Keith Patterson
Contact_Organization: Dewberry - Geospatial Services Group
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1000 N. Ashley Drive, Suite 801
City: Tampa
State_or_Province: FL
Postal_Code: 33602
Country: USA
Contact_Voice_Telephone: 813.225.1325
Contact_Facsimile_Telephone: 813.225.1385
Contact_Electronic_Mail_Address: kpatterson@dewberry.com
Hours_of_Service: 8:00 - 5:00 EST
Process_Step:
Process_Description:
The DEM is reviewed in ArcGIS with hillshades. Hillshades allow the analyst to view the DEM in 3D and to more efficiently locate and identify potential issues. Analysts review the DEM for incorrect water elevations and artifacts that are introduced during the raster creation process.
Source_Used_Citation_Abbreviation: One project hydro flattened DEM
Process_Date: 201008
Source_Produced_Citation_Abbreviation: Final Project Hydro Flattened DEM
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Keith Patterson
Contact_Organization: Dewberry - Geospatial Services Group
Contact_Position: Project Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 1000 N. Ashley Drive, Suite 801
City: Tampa
State_or_Province: FL
Postal_Code: 33602
Country: USA
Contact_Voice_Telephone: 813.225.1325
Contact_Facsimile_Telephone: 813.225.1385
Contact_Electronic_Mail_Address: kpatterson@dewberry.com
Hours_of_Service: 8:00 - 5:00 EST
Process_Step:
Process_Description: Imported into SDE.
Source_Used_Citation_Abbreviation:
C:\0ChrisWork\TaylorCreekReservoir_D2\FULL_DEM\taylor_dem\FGDC_TaylorCreek_DEM.xml
Process_Date: 20100909
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 18000
Column_Count: 14000
Vertical_Count: 1
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Transverse Mercator
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999941
Longitude_of_Central_Meridian: -81.000000
Latitude_of_Projection_Origin: 24.333333
False_Easting: 656166.666667
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 2.500000
Ordinate_Resolution: 2.500000
Planar_Distance_Units: survey feet
Geodetic_Model:
Horizontal_Datum_Name: D_NAD_1983_NSRS2007
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_Resolution: 1.000000
Altitude_Encoding_Method:
Explicit elevation coordinate included with horizontal coordinates
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: St. Johns River Water Management District
Contact_Position: GIS Data Manager, Information Resources Department
Contact_Address:
Address_Type: mailing and physical address
Address: 4049 Reid Street
City: Palatka
State_or_Province: FL
Postal_Code: 32177
Country: USA
Contact_Voice_Telephone: (386) 329-4500
Contact_Electronic_Mail_Address: gis_support@sjrwmd.com
Hours_of_Service: 0800-1700 ET
Resource_Description: Downloadable Data
Distribution_Liability:
The St. Johns River Water Management District prepares and uses information for its own purposes and this information may not be suitable for other purposes. This information is provided "as is". Further documentation of this data can be obtained by contacting: St. Johns River Water Management District, Division of Integrated Application Systems, 4049 Reid Street, Palatka, Florida, 32177, (386) 329-4500.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Transfer_Size: 969.211
Metadata_Reference_Information:
Metadata_Date: 20100910
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: St. Johns River Water Management District
Contact_Person: REQUIRED: The person responsible for the metadata information.
Contact_Position: GIS Data Manager, Information Resources Department
Contact_Address:
Address_Type: mailing and physical address
Address: 4049 Reid Street
City: Palatka
State_or_Province: FL
Postal_Code: 32177
Country: USA
Contact_Voice_Telephone: (386) 329-4500
Contact_Electronic_Mail_Address: gis_support@sjrwmd.com
Hours_of_Service: 0800-1700 ET
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Generated by mp version 2.9.6 on Fri Sep 10 14:57:02 2010