ESA SNAP v10 – What’s new?

Hello EO-Masters!

We had to wait for almost two years for the next major release of SNAP, ESA's Earth Observation processing and analysis application. Let's see if it was worth the wait.

Disclaimer: Before going into the details, I should say that I was leading the development team till June 2023. So, I worked on quite some of the new features.

If you can't wait anymore and want to use SNAP immediately, you can download it here:

SNAP Download – STEP (esa.int)

You prefer to watch a video?

Then you can check this out one on YouTube.

New Visuals and new Toolboxes

Let’s start with the most obvious change. The graphics design.

New startup-screen, new icons and so on. The default Look & Feel has changed too, and now SNAP Desktop looks more modern.

The new look is quite nice and refreshing.

The second noticeable change is the change in the structure of the toolboxes. The previous Sentinel-1, -2, -3 Toolboxes have been replaced with a Microwave and an Optical Toolbox. The Microwave Toolbox combines the Sentinel-1 and the RadarSat Toolbox and the Sentinel-2 and -3 Toolboxes and the Proba-V Toolbox are merged into the Optical Toolbox.

Under the Hood

A lot of changes have been made under the hood for this release that were needed for the future. Necessary to continue to provide an application that is at the forefront of technology and offers a high-performance user experience. This is why less new features are included in this release, because a lot of time was spent in the groundwork. More needs to be done and will be done, as far as I know the plans.For example, some of the major 3rd party libraries have been updated to more recent versions.

GDAL has been updated to version 3.7.2, GeoTools to version 28.2 and several other libraries have been updated too. But the most important updates where those of NetBeans (now 11.3 version) and Java (now based on JDK 11). To make SNAP using these new versions took a big amount of development time.

The updates of the libraries and the restructuring lead also to several changes in the API. These changes are of interest of developers and are noted in the SNAP wiki.

Thanks to these updates, SNAP works again on macOS. The GUI was broken since the Ventura update.

Other architectural changes affect the SNAP Python bridge snappy.

The snappy module has been renamed to esa_snappy. This renaming solves the conflict with other python modules with the same name. Now it also supports Python up to version 3.10. It has been promoted to a new top-level module and is available at GitHub - senbox-org/esa-snappy. Other helpful resources to familiarise with the new esa_snappy are:

• Access to SNAP Java API from Python

• How to use the SNAP API from Python

• Configure Python to use the new SNAP-Python (esa_snappy) interface

Now SNAP also supports the ARM processor architecture. Which is most important for Mac users. To support this, other libraries, like the NetCDF library had to be updated.

New Features

The Microwave Toolbox supports the new Extended Timing Annotation Dataset (ETAD) products.

This dataset for Copernicus Sentinel-1 is a new auxiliary product developed by DLR under contract to ESA, providing users with corrections to improve geometric accuracy of Sentinel-1 SLC images to centimetric levels. The Microwave Toolbox is now able to

• read and display ETAD products.

• apply ETAD Correction for GRD and SM SLC products.

Other resources about ETAD are:

• Sentinel-1 Extended Timing Annotation (ETAD) - Product Definition Document

• The Extended Timing Annotation Dataset for Sentinel-1—Product Description and First Evaluation Results

😢Unfortunately the ETAD support has been removed shortly before the release. 😢

S1 COG GRD products and the Cosmo-Skymed Second Generation products in HDF and GeoTiff format are also supported by the Microwave Toolbox.

Noteworthy for the Optical Toolbox is that the Jpeg2000 data files of Sentinel-2 are now read directly without the conversion to temporary Tiff files. This makes the S2 cache obsolete and saves disk space on the user’s system. A geolocation issue with Sentinel-3 WST products has been solved. Landsat C2 data provided as tar files from USGS can now be opened directly.

Software Improvements

The content of several help pages has been updated to bring the help in line with the software. The general startup time of SNAP has been improved, by doing the initialisation of the ProductLibrary and GDAL only when it is first used. Also fixes and improvements have been applied to several product data readers. The Product Library can also access the Copernicus DataSpace.

The release notes tell that the SNAP Plugin Dialog has been customised to allow voting for plugins. Unfortunately, I don’t see this feature implemented. Maybe there is still something missing?

More Improvements

There is now a dedicated release notes page named Public Roadmap and Changelog. This is very good and useful as you can navigate back and forth through the versions and see what has changed and what is planned for the future.

The help pages available in SNAP are now also available online. This makes the help more accessible and sharing links to the help pages is now possible. Those help pages include the help of all plugins available at the plugin repository. This allows to read the help of tools you haven’t installed yet.

The build pipeline which creates the installer for SNAP has been recreated from scratch. It does not only create the installer file, but also performs the automatic testing of the software. This includes the integration test for data readers and writers, the GPF operators and thousands of small unit level tests. This shall ensure faster development cycles but even more importantly a better quality-assurance of SNAP releases.

Another interesting change for developers is that when contributing a code change to the SNAP project a Contributor License Agreement (CLA) needs to be signed now. Its purpose is to clarify the legal rights and responsibilities of both the contributors and the project maintainers.

The CLA Signing Instructions describe how the procedure of signing works.

Summary

I think the thematic restructuring makes sense. All three toolboxes did support more platforms and sensors as only the Sentinels. Also, there was no clear separation between the S2- and S3-Toolbox because features of the one toolbox where applicable to sensors of the other toolbox.

Only that S1-Toolbox has been renamed to Microwave is a bit confusing, I think, because it indicates that also the SMOS Box is included, which is not. Maybe, Radar Toolbox would have been a better choice. Maybe SMOS will be included in the future.

Long outstanding tasks such as updating the libraries were also addressed. This was very necessary to keep SNAP at the edge of technology and further updates are still necessary. Improvements to GPF, it’s performance and memory consumption are needed too. And the developers have this on their roadmap.

Unfortunately, the update for the ARM architecture was only done for Mac. The chance to also support Windows on ARM has been missed. Maybe this will come with SNAP 11?

So, I think this is a really good release, even if it has fewer new features than previous releases. But by improving the basis everyone will benefit. Users get a more reliably application and the developers can develop new features faster and with higher quality in the future.

Hopefully, the next release won't take so long. Otherwise, I can image SNAP might lose users because it can hold track with actual development in the EO and the software domain.

To complete this overview of ESA’s SNAP 10 release let me provide you the link to the complete list of software changes. This gives a list of more than 120 issues that have been addressed for this release.

EOMasters plugins

And finally, as now SNAP 10 has been released I can also release my own plugins.

There is the free plugin of EOMasters Toolbox which provides general usability enhancements and features. And there is the Data Validation Environment DAVALIEN, which helps you to validated generated data even when you haven’t used SNAP for the generation.

And I also work on a third free plugin which is still a secret. But also, this will be released soon. I hope 🙂.

And as if this is not enough there is the PRO version of the EOMasters Toolbox in development. Providing new tools to the user. But this will take a little longer till it can be released.

I’m excited, are you?

Tschüs and Goodbye

  Marco