ImageEnvelope - Image Envelope
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Extracts an image envelope.

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

Build a vector data containing the image envelope polygon. Useful for some projection, you can set the polygon with more points with the sr parameter. This filter supports user-specified output projection. If no projection is defined, the standard WGS84 projection will be used.

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 *ImageEnvelope* .

.. [#] Table: Parameters table for Image Envelope.

+-------------+----------------------------------+--------------------------+
|Parameter Key|Parameter Name                    |Parameter Type            |
+=============+==================================+==========================+
|in           |Input Image                       |Input image               |
+-------------+----------------------------------+--------------------------+
|out          |Output Vector Data                |Output vector data        |
+-------------+----------------------------------+--------------------------+
|sr           |Sampling Rate                     |Int                       |
+-------------+----------------------------------+--------------------------+
|elev         |Elevation management              |Group                     |
+-------------+----------------------------------+--------------------------+
|elev.dem     |DEM directory                     |Directory                 |
+-------------+----------------------------------+--------------------------+
|elev.geoid   |Geoid File                        |Input File name           |
+-------------+----------------------------------+--------------------------+
|elev.default |Default elevation                 |Float                     |
+-------------+----------------------------------+--------------------------+
|proj         |Projection                        |String                    |
+-------------+----------------------------------+--------------------------+
|inxml        |Load otb application from xml file|XML input parameters file |
+-------------+----------------------------------+--------------------------+
|outxml       |Save otb application to xml file  |XML output parameters file|
+-------------+----------------------------------+--------------------------+

**Input Image**: Input image filename.

**Output Vector Data**: Vector data file containing the envelope.

**Sampling Rate**: Sampling rate for image edges (in pixel).

**[Elevation management]**: This group of parameters allows managing elevation values. Supported formats are SRTM, DTED or any geotiff. DownloadSRTMTiles application could be a useful tool to list/download tiles related to a product.

- **DEM directory**: This parameter allows selecting a directory containing Digital Elevation Model files. Note that this directory should contain only DEM files. Unexpected behaviour might occurs if other images are found in this directory.
- **Geoid File**: Use a geoid grid to get the height above the ellipsoid in case there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles. A version of the geoid can be found on the OTB website (http://hg.orfeo-toolbox.org/OTB-Data/raw-file/404aa6e4b3e0/Input/DEM/egm96.grd).
- **Default elevation**: This parameter allows setting the default height above ellipsoid when there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles, and no geoid file has been set. This is also used by some application as an average elevation value.

**Projection**: Projection to be used to compute the envelope (default is WGS84).

**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_ImageEnvelope -in QB_TOULOUSE_MUL_Extract_500_500.tif -out ImageEnvelope.shp

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 ImageEnvelope application 
	ImageEnvelope = otbApplication.Registry.CreateApplication("ImageEnvelope")

	# The following lines set all the application parameters:
	ImageEnvelope.SetParameterString("in", "QB_TOULOUSE_MUL_Extract_500_500.tif")

	ImageEnvelope.SetParameterString("out", "ImageEnvelope.shp")

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

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

None

Authors
~~~~~~~

This application has been written by OTB-Team.