# Superimpose¶

Using available image metadata, project one image onto another one

## Description¶

This application performs the projection of an image into the geometry of another one.

## Parameters¶

Reference input -inr image Mandatory
The input reference image.

The image to reproject -inm image Mandatory
The image to reproject into the geometry of the reference input.

Output image -out image [dtype] Mandatory
Output reprojected image.

### 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.

Spacing of the deformation field -lms float Default value: 4
Generate a coarser deformation field with the given spacing

Fill Value -fv float Default value: 0
Fill value for area outside the reprojected image

Mode -mode [default|phr] Default value: default
Superimposition mode

• Default mode
Default superimposition mode : uses any projection reference or sensor model found in the images
Pleiades superimposition mode, designed for the case of a P+XS bundle in SENSOR geometry. It uses a simple transform on the XS image : a scaling and a residual translation.

Interpolation -interpolator [bco|nn|linear] Default value: bco
This group of parameters allows defining how the input image will be interpolated during resampling.

• Bicubic interpolation
Bicubic interpolation leads to very good image quality but is slow.
• Nearest Neighbor interpolation
Nearest neighbor interpolation leads to poor image quality, but it is very fast.
• Linear interpolation
Linear interpolation leads to average image quality but is quite fast

### Bicubic interpolation options¶

Radius for bicubic interpolation -interpolator.bco.radius int Default value: 2
This parameter allows controlling the size of the bicubic interpolation filter. If the target pixel size is higher than the input pixel size, increasing this parameter will reduce aliasing artifacts.

Available RAM (MB) -ram int Default value: 256
Available memory for processing (in MB).

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_Superimpose -inr QB_Toulouse_Ortho_PAN.tif -inm QB_Toulouse_Ortho_XS.tif -out SuperimposedXS_to_PAN.tif


From Python:

import otbApplication

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

app.SetParameterString("inr", "QB_Toulouse_Ortho_PAN.tif")
app.SetParameterString("inm", "QB_Toulouse_Ortho_XS.tif")
app.SetParameterString("out", "SuperimposedXS_to_PAN.tif")

app.ExecuteAndWriteOutput()