Topographic Wetness Index (TWI)


Identification_Information:
Citation:
Citation_Information:
Originator:Brydon H. Lidle, III, Susquehanna River Basin Commission, Manager, Information Technology
Publication_Date:20180315
Title:
Topographic Wetness Index (TWI)
Geospatial_Data_Presentation_Form:remote-sensing image
Online_Linkage: http://www.pasda.psu.edu/
Description:
Abstract:
GIS raster datasets displaying Topographic Wetness Index (TWI) for Adams, Franklin, Lancaster, and York Counties, PA. The TWI rasters were derived from 2015 LiDAR for Lancaster and York Counties and 2006-08 LiDAR for Adams and Franklin Counties. The TauDEM extension (D-Infinity tools) for ArcMap was used to create flow direction, slope, and contributing area rasters. TWI was then calculated using the following equation: Ln (Contributing Area/Slope). The methodology was described by Cody Fink in his 2013 thesis entitled Dynamic Soil Property Change in Response to Natural Gas Development in Pennsylvania. TWI results in a dimensionless raster and should be displayed using a red (low values representing no flow) to blue (high, representing high probability flowpaths) color gradient. TWI results vary depending on raster size and analysis options so value thresholds for probability-based overland flowpaths for water should be field verified.
Purpose:
Dataset developed to fit the needs of the Susquehanna River Basin Commission.
Supplemental_Information:
Largest scale to be used when displaying the data-
Status:
Maintenance_and_Update_Frequency:None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate:-76.679449
East_Bounding_Coordinate:-76.224425
North_Bounding_Coordinate:40.000548
South_Bounding_Coordinate:39.701415
Keywords:
Theme:
Theme_Keyword_Thesaurus:ISO 19115 Topic Categories
Theme_Keyword:elevation
Theme_Keyword:environment
Theme_Keyword:geoscientificInformation
Theme_Keyword:imageryBaseMapsEarthCover
Theme_Keyword:inlandWaters
Theme:
Theme_Keyword:TWI
Theme_Keyword:LiDAR
Theme_Keyword:Topographic Wetness Index
Theme_Keyword:imageryBaseMapsEarthCover
Theme_Keyword:water
Theme_Keyword:elevation
Theme_Keyword:geoscientificInformation
Theme_Keyword:flow paths
Theme_Keyword:inlandWaters
Theme_Keyword:imageryBaseMapsEarthCover
Theme_Keyword:inlandWaters
Theme_Keyword:environment
Theme_Keyword:geoscientificInformation
Theme_Keyword:elevation
Place:
Place_Keyword_Thesaurus:None
Place_Keyword:York County
Place_Keyword:Pennsylvania
Place_Keyword:Susquehanna River Basin
Place_Keyword:Lancaster County
Access_Constraints:No access constraints, dataset is available for public use.
Use_Constraints:
The Originator, Publisher, and Distributor exclude any and all express or implied warranties and make no warranty or representation with respect to the data files or accompanying documentation, including quality, performance, merchantability or fitness for a particular purpose. These data files and documentation are provided "as is" and the User assumes the entire risk as to their quality and performance. These data are not to be redistributed for commercial profit. Reproduction or redistribution of this digital dataset without permission of the Originator/Publisher is expressly forbidden. The Originator and Publisher should be clearly cited in any product derived from this data. Any modifications to this data must be described in any digital or hardcopy product derived from this data. The SRBC assumes no legal liability for the accuracy or completeness of the data for any use. In no event shall the SRBC have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Susquehanna River Basin Commission
Contact_Person:Brydon H. Lidle, III
Contact_Position:Manager, Information Technology
Contact_Address:
Address_Type:mailing and physical
Address:
4423 North Front Street
City:Harrisburg
State_or_Province:PA
Postal_Code:17110-1788
Country:US
Contact_Voice_Telephone:717-238-0423
Contact_Facsimile_Telephone:717-238-2436
Contact_Electronic_Mail_Address:blidle@srbc.net
Hours_of_Service:8 AM to 4 PM, M - F
Data_Set_Credit:
Jamie Shallenberger, SRBC, and Cody M. Fink.
Native_Data_Set_Environment:
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.4.1.5686
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Data_Quality_Information:
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Publication_Date:20150424
Title:
NJ/PA Sandy LiDAR
Online_Linkage: http://www.pasda.psu.edu/uci/DataSummary.aspx?dataset=382
Type_of_Source_Media:onLine
Source_Citation_Abbreviation:
NJ/PA Sandy LiDAR
Source_Contribution:
2015 Sandy LiDAR 
Process_Step:
Process_Description:
Sandy LiDAR DEMs merged into southeast York County extent.  Merged DEM reprojected to PA State Plane South Feet and smoothed using neighborhood statistics (circle, 13.12', mean).  TauDEM D-Infinity Flow Direction analysis and D-Infinity Contributing Area calculated (no check for edge contamination).  TWI calculated using raster calculator and equation: Ln(contributing area/slope).
Process_Date:20180315
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:SRBC
Contact_Person:Jeff Zimmerman, Jr.
Contact_Position:GIS Developer
Contact_Address:
Address_Type:mailing and physical
Address:
4423 North Front Street
City:Harrisburg
State_or_Province:PA
Postal_Code:17110-1788
Country:US
Contact_Voice_Telephone:717-238-0432
Contact_Facsimile_Telephone:717-238-2436
Contact_Electronic_Mail_Address:jzimmerman@srbc.net
Hours_of_Service:M - F, 8 AM to 4 PM
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Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method:Raster
Raster_Object_Information:
Raster_Object_Type:Pixel
Row_Count:33477
Column_Count:39437
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Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Lambert_Conformal_Conic:
Standard_Parallel:39.93333333333333
Standard_Parallel:40.96666666666667
Longitude_of_Central_Meridian:-77.75
Latitude_of_Projection_Origin:39.33333333333334
False_Easting:1968500.0
False_Northing:0.0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method:coordinate pair
Coordinate_Representation:
Abscissa_Resolution:0.000000026907964745248598
Ordinate_Resolution:0.000000026907964745248598
Planar_Distance_Units:foot_us
Geodetic_Model:
Horizontal_Datum_Name:D North American 1983
Ellipsoid_Name:GRS 1980
Semi-major_Axis:6378137.0
Denominator_of_Flattening_Ratio:298.257222101
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Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label:XMLMetadataTemplate
Attribute:
Attribute_Label:FID
Attribute_Definition:
Internal feature number.
Attribute_Definition_Source:
ESRI
Attribute_Domain_Values:
Unrepresentable_Domain:
Sequential unique whole numbers that are automatically generated.
Attribute:
Attribute_Label:Shape
Attribute_Definition:
Feature geometry.
Attribute_Definition_Source:
ESRI
Attribute_Domain_Values:
Unrepresentable_Domain:
Coordinates defining the features.
Attribute:
Attribute_Label:AREANAME
Attribute:
Attribute_Label:CLASS
Attribute:
Attribute_Label:ST
Attribute:
Attribute_Label:STFIPS
Attribute:
Attribute_Label:PLACEFIP
Attribute:
Attribute_Label:HOUSEUNITS
Attribute:
Attribute_Label:POPULATION
Attribute:
Attribute_Label:POP_CL
Attribute:
Attribute_Label:AREALAND
Attribute:
Attribute_Label:AREAWATER
Attribute:
Attribute_Label:SUSQ_MJR
Attribute:
Attribute_Label:X
Attribute:
Attribute_Label:Y
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:SRBC
Contact_Person:Brydon H. Lidle, III
Contact_Position:Manager, Information Technology
Contact_Address:
Address_Type:mailing and physical
Address:
4423 North Front Street
City:Harrisburg
State_or_Province:PA
Postal_Code:17110-1788
Country:US
Contact_Voice_Telephone:717-238-0425
Contact_Facsimile_Telephone:717-238-2436
Contact_Electronic_Mail_Address:blidle@srbc.net
Hours_of_Service:8 AM to 4 PM, M - F
Distribution_Liability:
Use of map for any purpose on “as is” basis, no warranties provided.
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Susquehanna River Basin Commission
Contact_Person:Brydon H. Lidle, III
Contact_Position:Manager, Information Technology
Contact_Address:
Address_Type:mailing and physical
Address:
4423 North Front Street
City:Harrisburg
State_or_Province:PA
Postal_Code:17110-1788
Country:US
Contact_Voice_Telephone:717-238-0423
Contact_Facsimile_Telephone:717-238-2436
Contact_Electronic_Mail_Address:blidle@srbc.net
Hours_of_Service:8 AM to 4 PM, M - F
Distribution_Liability:
Use of map for any purpose on “as is” basis, no warranties provided.
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Pennsylvania Spatial Data Access (PASDA)
Contact_Address:
Address_Type:mailing and physical address
Address:
115 Land and Water building
City:University Park
State_or_Province:Pennsylvania
Postal_Code:16802
Country:United States
Contact_Voice_Telephone:(814) 865 - 8792
Contact_Electronic_Mail_Address:pasda@psu.edu
Distribution_Liability:
The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.
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Metadata_Reference_Information:
Metadata_Date:20180322
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:SRBC
Contact_Person:Jeff Zimmerman, Jr.
Contact_Position:GIS Developer
Contact_Address:
Address_Type:mailing and physical address
Address:
4423 North Front Street
City:Harrisburg
State_or_Province:PA
Postal_Code:17110-1788
Country:US
Contact_Voice_Telephone:717-238-0432
Contact_Facsimile_Telephone:717-238-2436
Contact_Electronic_Mail_Address:jzimmerman@srbc.net
Hours_of_Service:M - F, 8 AM to 4 PM
Metadata_Standard_Name:FGDC Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version:FGDC-STD-001-1998
Metadata_Time_Convention:local time
Metadata_Access_Constraints:There are no access constraints for this metadata document.
Metadata_Use_Constraints:
There are no use constraints for this metadata document.
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