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snippet: CETWI TWI Metadata service provided by USDA-FPAC
summary: CETWI TWI Metadata service provided by USDA-FPAC
extent: [[-126.994369886699,25.7716554817171],[-90.0625119730228,49.662522309312]]
accessInformation: CETWI TWI Metadata Service provided by USDA-FPAC
thumbnail: thumbnail/thumbnail.png
maxScale: 1.7976931348623157E308
typeKeywords: ["Data","Service","Map Service","ArcGIS Server"]
description: <div style='text-align:Left;'><div><div><p style='margin:0 0 0 0;'><span style='font-size:12pt'>The</span><span style='font-weight:bold;font-size:12pt'> </span><span style='font-size:12pt'>Topographic Wetness Index (TWI)</span><span style='font-weight:bold;font-size:12pt'> </span><span style='font-size:12pt'>is a steady-state wetness index that attempts to quantify the water movement on landforms and landscapes. The conventional Topographic Wetness Index is created in a Geographic Information Systems and defined as ln(</span><span style='font-style:italic;font-size:12pt'>a</span><span style='font-size:12pt'>/tan </span><span style='font-style:italic;font-size:12pt'>β</span><span style='font-size:12pt'>), the logarithm of the area divided by the tangent of the local slope. The conventional TWI is an index that correlates water movement on similar sloped landforms that have the same TWI index value. It is an interpretation of USGS digital elevation model (DEM) slope, and the upstream area used in its analysis. Any estimate of water accumulation is based on the finite areas determined within the calculation area. Slope and upstream surface area are the only two derivatives used in defining TWI. TWI performs best on sloping uplands but deteriorates in flat landscapes.</span></p><p style='margin:0 0 0 0;'><span /><span /></p><p style='margin:0 0 11 0;'><span style='font-weight:bold;font-size:12pt'>Purpose:</span><span style='font-size:12pt'> The TWI is a valuable index for understanding the relationship between topography and hydrology before making a field visit. It can help identify areas that are prone to water accumulation and can be used to assess the potential for wetland development. However, the standard TWI has design limitations that has been overcome with the development of the Climate Enhanced Topographic Wetness Index. </span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Creation Date:</span><span> 20240507</span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Publication Date: </span><span>20240507</span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Revision Date: </span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Refresh Cycle: </span><span>Updated periodically as new imagery becomes available</span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Version: </span><span>1.0.0</span></p><p style='font-size:12pt'><span style='font-weight:bold;'>Change Log:</span><span> Service Deployed</span></p><p style='font-size:12pt'><a href='mailto:usdafpacbc@servicenowservices.com?Subject=GEOSRV' style='text-decoration:underline;'><span style='font-weight:bold;'>Report Service Errors</span></a></p><p><span /></p></div></div></div>
licenseInfo: USDA
catalogPath:
title: cetwi_twi_2022_10m_metadata
type: Map Service
url:
tags: ["USDA-FPAC","CETWI","Metadata","v1"]
culture: en-US
name: cetwi_twi_2022_10m_metadata
guid: F7E986FD-89B4-409D-8E82-364F805A91C2
minScale: 0
spatialReference: WGS_1984_Web_Mercator_Auxiliary_Sphere