Name: Topographic Wetness Index

Display Field: Shape_Leng

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description: The TWI is a physically based index or indicator of the effect of local topography on runoff flow direction and accumulation. The index is a function of both the slope and the upstream contributing area.The computation of TWI is performed using both geographic information systems (GIS) and Python, a programing software used to enhance computing capabilities. The indices help identify rainfall runoff patterns, areas of potential increased soil moisture, and ponding areas. Illinois State Water Survey generated the index to the Illinois counties of DuPage and Will (see report at http://hdl.handle.net/2142/98495), but has subsequently generated the index for all Illinois counties. The DEM used for this county was derived from LiDAR acquired in 2017. While TWI is usually viewed in raster format, ISWS is distributing a version in polygon format for easier access and use.

Copyright Text: Illinois State Water Survey

Default Visibility: false

MaxRecordCount: 1000

Supported Query Formats: JSON, geoJSON, PBF

Min Scale: 24000

Max Scale: 0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: false

Can Modify Layer: false

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:

XMin: -9874842.1344
YMin: 5158953.796899997
XMax: -9757646.79
YMax: 5235537.5546
Spatial Reference: 102100  (3857)

Drawing Info:

Renderer:
Simple Renderer:
Symbol:
Style: esriSFSSolid
Color: [102, 205, 171, 127]
Outline:
Style: esriSLSNull
Color: [110, 110, 110, 0]
Width: 0
Label: N/A
Description: N/A
Transparency: 0
Labeling Info:

Advanced Query Capabilities:

Supports Statistics: true
Supports OrderBy: true
Supports Distinct: true
Supports Pagination: true
Supports TrueCurve: true
Supports Returning Query Extent: true
Supports Query With Distance: true
Supports Sql Expression: true
Supports Query With ResultType: false
Supports Returning Geometry Centroid: false
Supports Binning LOD: false
Supports Query With LOD Spatial Reference: false
Supports Percentile Statistics: true
Supports Having Clause: true
Supports Count Distinct: true
Supports Time Relation: true
Supports Sql Format: false
Supports Query Analytic: true
Supports Query With Current User: true

HasZ: false

HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:

• OBJECTID ( type: esriFieldTypeOID, alias: OBJECTID )
• Shape_Leng ( type: esriFieldTypeDouble, alias: Shape_Leng )
• Shape ( type: esriFieldTypeGeometry, alias: Shape )
• Shape.STArea() ( type: esriFieldTypeDouble, alias: Shape.STArea() )
• Shape.STLength() ( type: esriFieldTypeDouble, alias: Shape.STLength() )

Supported Operations:   Query   Query Attachments   Query Analytic   Generate Renderer   Return Updates

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