Module Transect through polygon shapefile

Transect for lines and polygon shapefiles

The goal of this module is to create a transect along a line through a polygon map.
Eg

|____ST1_____!_ST2_!__ST1__!_______ST#_____|

(Soil type 1 etc...)

This is done by creating a table with the ID of each line, the distance
to the starting point and the different transects:

|  line_id  |  start  |  end  |  code/field  |
|    0      |    0    |  124  |     ST1      |
|    0      |   124   |  300  |     ST2      |
|    0      |   300   | 1223  |     ST1      |
|    0      |  1223   | 2504  |     ST3      |
|    1      |    0    |  200  |     ST4      |
|   ...     |   ...   |  ...  |     ...      |

The module requires an input shape with all the line transects [Transect_Line]
and a polygon theme [Theme]. You also have to select which field you want to have in
the resulting table [Transect_Result]. This can be an ID of the polygon theme if you
want to link the tables later on, or any other field [Theme_Field].

Author: Copyrights (c) 2009 Johan Van de Wauw
Specification: grid
Menu: Shapes|Lines|Transects

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Line Transect(s)	Shapes (input)	`TRANSECT`	-	-
Input	Theme	Shapes (input)	`THEME`	-	-
Output	Result table	Table (output)	`TRANSECT_RESULT`	-	-
Options	Theme Field (*)	Table field	`THEME_FIELD`	-	-
(*) optional

Command-line

Usage: saga_cmd shapes_transect 0 [-TRANSECT <str>] [-THEME <str>] [-THEME_FIELD <str>] [-TRANSECT_RESULT <str>]
  -TRANSECT:<str>       	Line Transect(s)
	Shapes (input)
  -THEME:<str>          	Theme
	Shapes (input)
  -THEME_FIELD:<str>    	Theme Field
	Table field
  -TRANSECT_RESULT:<str>	Result table
	Table (output)