Please cite SAGA whenever you use it for your publications:

Line properties: length, number of vertices.

Name	Type	Identifier	Description	Constraints
Input
Lines	shapes, input	LINES
Output
Lines with Property Attributes	shapes, output, optional	OUTPUT	If not set property attributes will be added to the original layer.
Options
Copy Attributes	table fields	FIELDS	Select one or more attributes to be copied to the target layer.
Number of Parts	boolean	BPARTS		Default: 0
Number of Vertices	boolean	BPOINTS		Default: 0
Length	boolean	BLENGTH		Default: 1
Scaling	floating point number	SCALING	Scaling factor for length property. meter to feet = 1 / 0.3048 = 3.2808	Minimum: 0.000000 Default: 1