Extract ROI

Extract a ROI defined by the user.

Detailed description

This application extracts a Region Of Interest with user defined size, or reference image.

Parameters

This section describes in details the parameters available for this application. Table [1] presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is ExtractROI .

[1]Table: Parameters table for Extract ROI.
Parameter Key Parameter Type Parameter Description
in Input image Input image
out Output image Output image
ram Int Int
mode Choices Choices
mode standard Choice Standard
mode fit Choice Fit
mode.fit.ref Input image Input image
mode.fit.elev Group Group
mode.fit.elev.dem Directory Directory
mode.fit.elev.geoid Input File name Input File name
mode.fit.elev.default Float Float
startx Int Int
starty Int Int
sizex Int Int
sizey Int Int
cl List List
inxml XML input parameters file XML input parameters file
outxml XML output parameters file XML output parameters file

Input Image: Input image.

Output Image: Output image.

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

Extraction mode Available choices are:

  • Standard: In standard mode, extract is done according the coordinates entered by the user.
  • Fit: In fit mode, extract is made to best fit a reference image.
  • Reference image: Reference image to define the ROI.
  • 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.

Start X: ROI start x position.

Start Y: ROI start y position.

Size X: size along x in pixels.

Size Y: size along y in pixels.

Output Image channels: Channels to write in the output image.

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_ExtractROI -in VegetationIndex.hd -startx 40 -starty 250 -sizex 150 -sizey 150 -out ExtractROI.tif

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

# The following lines set all the application parameters:
ExtractROI.SetParameterString("in", "VegetationIndex.hd")

ExtractROI.SetParameterInt("startx", 40)

ExtractROI.SetParameterInt("starty", 250)

ExtractROI.SetParameterInt("sizex", 150)

ExtractROI.SetParameterInt("sizey", 150)

ExtractROI.SetParameterString("out", "ExtractROI.tif")

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

Limitations

None

Authors

This application has been written by OTB-Team.