DRAIN

Description

Generates a drainage network data set using input flow accumulation data.

Parameters

Name	Type	Length	Value range
Input: Flow accumulation channel*	Raster port	1 - 1	1 - 1024
Output: Output drainage channel*	Raster port	1 - 1	1 - 1024
Drainage Threshold	Integer	0 - 1	0 - Default: 10
Layer Descriptive Text	String	0 - 1	Default: Drainage Network

* Required parameter

Parameter descriptions

Input: Flow accumulation channel

Specifies the input channel that contains the flow accumulation data, output by DWCON.

Output: Output drainage channel

Specifies the output channel to receive the drainage result. The specified output channel should be of the same type as the input channel (FACCUM); that is, either 16-bit signed integer or 32-bit real.

Drainage Threshold

Specifies the drainage threshold.

If the value of the accumulation data is less than or equal to the value specified for this parameter, the value will be set to zero. Therefore, only data with accumulation values greater than the specified threshold value will be copied to the output channel.

Layer Descriptive Text

Describes (in up to 64 characters) the contents of the output channel.

The default value is "Drainage Network".

Details

DRAIN generates a drainage network data set channel using the input flow accumulation data.

There are a total of six functions in this component: DWCON, DRAIN, OVERLND, PPTABLE, SEED, and WTRSHED. To use this functionality, you must first run the DWCON module. Refer to the help for the DWCON function for more information about the workflow for these functions.

The DRAIN function locates the drainage networks (river or stream courses) within the DEM. The output data channel can be viewed using CATALYST Professional Focus. The data will appear as lines representing rivers and streams.

After DWCON is executed, the flow accumulation data set can be used to produce a drainage network data set when cells with values greater than the threshold value (DRNTHR) are selected. The density of the network increases as the threshold value decreases.

The input channel (FACCUM) specifies the flow accumulation data set channel obtained by running the DWCON function.

References

Jenson, S.K. and Domingue, J.O. "Extracting Topographic Structure from Digital Elevation Data for Geographic Information System Analysis". Photogrammetric Engineering and Remote Sensing, Vol. 54, No. 11, November 1988, pp. 1593-1600.