Polygon Class Statistics
^^^^^^^^^^^^^^^^^^^^^^^^

Computes statistics on a training polygon set.

Detailed description
--------------------

The application processes a set of geometries intended for training (they should have a field giving the associated class). The geometries are analysed against a support image to compute statistics : 
  - number of samples per class
  - number of samples per geometry
An optional raster mask can be used to discard samples. Different types of geometry are supported : polygons, lines, points. The behaviour is different for each type of geometry :
  - polygon: select pixels whose center is inside the polygon
  - lines  : select pixels intersecting the line
  - points : select closest pixel to the point


Parameters
----------

This section describes in details the parameters available for this application. Table [#]_ presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is *PolygonClassStatistics* .

.. [#] Table: Parameters table for Polygon Class Statistics.

+-------------+--------------------------+----------------------------------+
|Parameter Key|Parameter Type            |Parameter Description             |
+=============+==========================+==================================+
|in           |Input image               |Input image                       |
+-------------+--------------------------+----------------------------------+
|mask         |Input image               |Input image                       |
+-------------+--------------------------+----------------------------------+
|vec          |Input File name           |Input File name                   |
+-------------+--------------------------+----------------------------------+
|out          |Output File name          |Output File name                  |
+-------------+--------------------------+----------------------------------+
|field        |String                    |String                            |
+-------------+--------------------------+----------------------------------+
|layer        |Int                       |Int                               |
+-------------+--------------------------+----------------------------------+
|ram          |Int                       |Int                               |
+-------------+--------------------------+----------------------------------+
|inxml        |XML input parameters file |XML input parameters file         |
+-------------+--------------------------+----------------------------------+
|outxml       |XML output parameters file|XML output parameters file        |
+-------------+--------------------------+----------------------------------+

- **InputImage:** Support image that will be classified.

- **InputMask:** Validity mask (only pixels corresponding to a mask value greater than 0 will be used for statistics).

- **Input vectors:** Input geometries to analyse.

- **Output Statistics:** Output file to store statistics (XML format).

- **Field Name:** Name of the field carrying the class name in the input vectors.

- **Layer Index:** Layer index to read in the input vector file.

- **Available RAM (Mb):** Available memory for processing (in MB).

- **Load otb application from xml file:** Load otb application from xml file.

- **Save otb application to xml file:** Save otb application to xml file.



Example
-------

To run this example in command-line, use the following: 
::

	otbcli_PolygonClassStatistics -in support_image.tif -vec variousVectors.sqlite -field label -out polygonStat.xml

To run this example from Python, use the following code snippet: 

::

	#!/usr/bin/python

	# Import the otb applications package
	import otbApplication

	# The following line creates an instance of the PolygonClassStatistics application 
	PolygonClassStatistics = otbApplication.Registry.CreateApplication("PolygonClassStatistics")

	# The following lines set all the application parameters:
	PolygonClassStatistics.SetParameterString("in", "support_image.tif")

	PolygonClassStatistics.SetParameterString("vec", "variousVectors.sqlite")

	PolygonClassStatistics.SetParameterString("field", "label")

	PolygonClassStatistics.SetParameterString("out", "polygonStat.xml")

	# The following line execute the application
	PolygonClassStatistics.ExecuteAndWriteOutput()

Limitations
~~~~~~~~~~~

None

Authors
~~~~~~~

This application has been written by OTB-Team.