Release of OTB 8.0 Alpha 1

Dear OTB community,

We are happy to announce that OTB version 8.0.0 Alpha 1 is available.

The main goal of release 8.0 is to remove OSSIM from OTB dependencies. This implies the refactoring of a lot of classes and functions, many of which are in the core modules of the library. The plan of this refactoring is detailed in this issue.
Before the actual release and release candidates, it is planned to release two alpha versions:

  • OTB 8.0.0-alpha1 : Optical processing without Ossim, OTB still depends on Ossim, but only use the library in SAR processing
  • OTB 8.0.0-alpha2 : SAR processing without ossim, OTB does not depend on Ossim.

As many users do not use the SAR functionalities of OTB, this first alpha gives you the opportunity to test the refactored functionalities before the actual release process. This includes:

  • The Metadata framework
  • The DEM Handler
  • The radiometry framework (optical calibration and filters)
  • The RPC model

Given the scale of the refactoring, particular attention should be given to the validation of these changes.
We welcome your feedback and requests on GitLab and if you find a bug, please report it.

The metadata framework

A new metadata framework is implemented. It is based on GDAL for reading and writing the metadata. Geom files won’t be written anymore. But OTB is still able to read them for retro-compatibility.

Internally, OSSIM’s keywordlists were replaced by the otb::ImageMetadata class that stores the metadata and propagates if through the pipeline. A set of classes are in charge of the interface between GDAL and otb::ImageMetadata. They are called Image Metadata Interface (IMI). There is one IMI for each sensor.

More details can be found in the documentation.

The DEM Handler

The DEM Handler is the mechanism in charge of loading the DEM and providing the elevations when needed. It benefits from GDAL’s ability to read and interpolate the DEM. It works with a single tile or a directory containing multiple tiles.

One unique instance of the otbDEMHandler class is accessible from any part of the application. When provided with the data, it creates a virtual in-memory vrt dataset, relying on GDAL’s vismem mechanism. This allows other classes to access the dataset if needed.

For more details, we invite you to read the documentation.

The RPC model

This alpha version comes with the first bricks of a new sensor model architecture, that will be able to select the sensor model to be used according to the available metadata. For now, only the RPC model is available. SAR model will come in next alpha.

The OTB now uses GDAL’s API to perform forward and inverse transformations with RPC model. It is able to use the DEMHandler to take into account the elevation and exploits GDAL’s vismem mechanism to avoid having to load the DEM multiple times.

The documentation brings more details.

Other improvements

  • Improvements in the interface of QGIS plugin.
  • Add the possibility to set new parameters for the kernels of libsvm.
  • Optimizations in BCO interpolator.


Ready to use binary packages are available on the package page of the website:

You can also checkout the release branch with git:

git clone OTB -b release-8.0

The documentation for OTB 8.0.0 can be found here

The OTB team.

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