# 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¶

Input Image -in image Mandatory
Input image filename.

Output Vector Data -out vectorfile Mandatory
Vector data file containing the envelope.

Sampling Rate -sr int Default value: 0
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 -elev.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 -elev.geoid filename [dtype]
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(https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb-data/blob/master/Input/DEM/egm96.grd).

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

Load parameters from XML -inxml filename.xml
Load application parameters from an XML file.

Save parameters to XML -outxml filename.xml
Save application parameters to an XML file.

## Examples¶

From the command-line:

otbcli_ImageEnvelope -in QB_TOULOUSE_MUL_Extract_500_500.tif -out ImageEnvelope.shp


From 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()