.. _ImageEnvelope: 

ImageEnvelope
=============





Extracts an image envelope.

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
----------

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**Input Image** :code:`-in image` *Mandatory* |br|
Input image filename.

**Output Vector Data** :code:`-out vectorfile` *Mandatory* |br|
Vector data file containing the envelope.

**Sampling Rate** :code:`-sr int` *Default value: 0* |br|
Sampling rate for image edges (in pixel).

Elevation management
^^^^^^^^^^^^^^^^^^^^



This group of parameters allows managing elevation values.

**DEM directory** :code:`-elev.dem directory` |br|
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. Input DEM tiles should be in a raster format supported by GDAL.

**Geoid File** :code:`-elev.geoid filename [dtype]` |br|
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 (egm96.grd and egm96.grd.hdr at https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb/-/tree/master/Data/Input/DEM).

**Default elevation** :code:`-elev.default float` *Default value: 0* |br|
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** :code:`-proj string` |br|
Projection to be used to compute the envelope (default is WGS84)



Examples
--------

From the command-line:

.. code-block:: bash

    otbcli_ImageEnvelope -in QB_TOULOUSE_MUL_Extract_500_500.tif -out ImageEnvelope.shp


From Python:

.. code-block:: python

	import otbApplication

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

	app.SetParameterString("in", "QB_TOULOUSE_MUL_Extract_500_500.tif")
	app.SetParameterString("out", "ImageEnvelope.shp")

	app.ExecuteAndWriteOutput()