Summary
Determines the contributing area above each input point. A watershed is the upslope area that contributes flow.
Usage
Tools in the Ready To Use toolbox are ArcGIS Online geoprocessing services that use hosted data and analysis capabilities in ArcGIS Online.
For each input point a watershed feature will be returned.
Output watershed features are the complete upstream area that contributes flow. For example, an input point, or pour point, on the Mississippi River in Louisiana will create a watershed feature including areas from New York to Montana into Canada.
A watershed feature will not be returned if the pour point does not fall inside the extent of the specified data source.
If no point identification field is specified, the unique ID field is used by default.
The maximum number of input points is 1000. If more input features are provided, the service will return an error and will not execute.
The pour point identification field must be of type integer or string. It is most useful to use a field consisting of unique values.
The output watershed feature dataset has a field called PointID consisting of the values supplied in the point identification field. This allows the watershed to easily be related back to the input points.
The resulting watershed feature dataset contains a field called AreaSqKm, which is the area in square kilometers for each watershed.
The default snapping distance is the resolution of the data in the specified database multiplied by 5.
The optional output of snapped points contain a field called PointID. This field contains the values supplied in the pour point ID field. This is used to relate the input pour points to their watersheds.
To provide feedback on this service, visit the Hydro forum.
Syntax
Watershed(InputPoints, {PointIDField}, {SnapDistance}, {SnapDistanceUnits}, {DataSourceResolution}, {Generalize}, {ReturnSnappedPoints})| Parameter | Explanation | Data Type |
InputPoints | The point features used for calculating watersheds. These are referred to as pour points, because it is the location at which water pours out of the watershed. | Feature Set |
PointIDField (Optional) | An integer or string field used to identify to the input points. The default is to use the unique ID field. | String |
SnapDistance (Optional) | The maximum distance to move the location of an input point. Interactive input points and documented gage locations may not exactly align with the stream location in the DEM. This parameter allows the service to move the point to a nearby location with the largest contributing area. By default, the snapping distance is calculated as the resolution of the source data multiplied by 5. | String |
SnapDistanceUnits (Optional) | The linear units specified for the snap distance.
| String |
DataSourceResolution (Optional) | Specifies the source data resolution that will be used in the analysis. The values are an approximation of the spatial resolution of the digital elevation model used to build the foundation hydrologic database. Since many elevation sources are distributed in units of arc seconds, an approximation is provided in meters for easier understanding.
| String |
Generalize (Optional) | Specifies whether the output watersheds will be smoothed into simpler shapes or conform to the cell edges of the original DEM.
| Boolean |
ReturnSnappedPoints (Optional) | Determines if a point feature at the watershed's pour point will be returned. If snapping is enabled, this might not be the same as the input point.
| Boolean |
Derived Output
| Name | Explanation | Data Type |
| WatershedArea | The output watershed. | Feature Set |
| SnappedPoints | The output snapped points. | Feature Set |