4.1.6 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 4.12, page 434
presents a summary of these parameters and the parameters keys to be used in command-line and
programming languages. Application key is ExtractROI.
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Parameter key | Parameter type |
Parameter description |
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in | Input image |
Input Image |
out | Output image |
Output Image |
ram | Int |
Available RAM (Mb) |
mode | Choices |
Extraction mode |
mode standard | Choice |
Standard |
mode fit | Choice |
Fit |
mode.fit.ref | Input image |
Reference image |
mode.fit.elev | Group |
Elevation management |
mode.fit.elev.dem | Directory |
DEM directory |
mode.fit.elev.geoid | Input File name |
Geoid File |
mode.fit.elev.default | Float |
Default elevation |
startx | Int |
Start X |
starty | Int |
Start Y |
sizex | Int |
Size X |
sizey | Int |
Size Y |
cl | List |
Output Image channels |
inxml | XML input parameters file |
Load otb application from xml file |
outxml | XML output parameters file |
Save otb application to xml file |
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Table 4.12: Parameters table for Extract ROI.
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.