SNAP in a Nutshell
Andrea Minchella ([email protected])
21-22/01/2016 – “ESA SNAP-Sentinel-1 Training Course”
Satellite Applications Catapult - Electron Building, Harwell, Oxfordshire
SNAP in a Nutshell
CATAPULT OPEN
What is SNAP?
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Sentinel Toolboxes Consortia
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Toolbox Evolution
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Toolbox Evolution
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Architecture Highlights
• Java, Python implementation
• Snap desktop: integrated graphical user-friendly interface;
• Snap engine (Graph Processing Tool): core and command line
interface;
• Graphical or command-line execution;
• Tiled memory management for working with very large data
products;
• Data abstraction models to handle all SAR missions in a common
way
• Modular design for easy modifications and upgrades
• Users are able to add their own modules via APIs
• Multithreading and Multi-core processor support
• Integrated WorldWind visualisation
SNAP in a Nutshell
CATAPULT OPEN
Source Code Repository
Credit: Sentinel-1 Toolbox – Open Source Tools for EOScience 2.0 @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Supported Platforms
• Windows (XP, Vista, 7, 8, 10)
• Linux
• Mac OS X
• 32 bit/64 bit
• Graphical User Interface
• Command-Line Interface
SNAP in a Nutshell
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Graph Processing Tool
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
SNAP Applicaton Modes
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
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Multi-Sensor Support
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Generic Functions and Tools
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
STEP (Science Toolbox Exploitation Platform)
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
https://step.esa.int EO Science collaborative platform
• SNAP software download
• SNAP tutorials and documentation
• Technical forum and community animation
• Gathering user feedback and usage
SNAP in a Nutshell
CATAPULT OPEN
Sentinel-1 Toolbox: evolution of NEST
https://earth.esa.int/web/nest/home/
Credit: Sentinel-1 Toolbox – Open Source Tools for EOScience 2.0 @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
Classification: CATAPULT OPEN
Example of Sentinel-1 data processing
Sentinel-1 toolbox architecture: data flow
Snap desktop (GUI)
Integrated graphical user interface for SAR data visualisation, analysis and processing
Graph Processing Tool (GPT)
For command line execution of user-definedbatch processing chains
WritersReaders Generic Product Model (GPM)
Sentinel-1
ENVISAT ASAR
ERS-1&2
Radarsat-2
Cosmo-SkyMed
TerraSAR-X
Tandem-x
ALOS PALSAR1&2
Radarsat-1
JERS SAR
Beam dimap
Geotiff
Netcdf
Envi
Generic Binary
Google Earth
PolSARpro
etc
SNAP in a Nutshell
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Generic Functions and Tools
• Statistics & Data Analysis
• Metadata handling
• Subset, Resample and Band Arithmetic
• Export to GeoTiff, HDF 4 & 5, NetCDF, Bynary, Envi, Kmz formats
• LUT and Layer Management
• ROI tools, layer stacking
• ….
SNAP in a Nutshell
CATAPULT OPEN
SAR Functionality
• Left and right facing missions displayed by start time and near range
• Absolute calibration
• Multilooking
• speckle (single and multitemporal) filtering
• Precise orbit handling (Doris, Prare and Delft orb.)
• Coregistration of detected and complex products
• Debursting of ASAR WSS
• Range-Doppler Terrain Correction
• Radiometric normalization during Terrain Correction
• SAR simulation
• Layover and shadow masks
• Simulated SAR Terrain Correction
• Ellipsoid correction, Map Reprojection, Mosaicking
• Automatic DEM download and tile selection
• Product library for scanning and cataloguing large archives efficiently
SNAP in a Nutshell
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SAR Functionality
• Ocean tools: basic routines for oil spill detection, ship detection and wind field
estimation from SAR data
• Inteferometry for Strimap and Zero-Doppler focused data
• Compatibility with ESA PolSARpro Toolbox (Reader, Writer)
Level of support depends on sensor & product type. Please refer to documentation for full
details such as the Operators help
But useful also to consult the “Supported_Products&MainTools.xls” available in the
Documentation page on NEST website https://earth.esa.int/web/nest/home/
SNAP in a Nutshell
CATAPULT OPEN
InSAR
Architecture Highlights
• Coregistration and resampling
• DEM assisted coregistration
• Products: interferogram and coherence
• Filtering: both spectral and phase
• Geo-coding
• Unwrapping via 3rd party sw(SNAPHU)
• Phase to height conversion
• Differential InSAR
• Cross InSAR (ERS-ENVISAT)
Only zero doppler and strip map
data are fully supported
SNAP in a Nutshell
CATAPULT OPEN
Ocean Tools
Land Masked Detection Map Projected
• Object (ship) Detection
• Oil Spill Detection
• Wind Field Estimation
• Create Land Mask
SNAP in a Nutshell
CATAPULT OPEN
New Sentinel-1 Functionality
• Calibration
• Thermal Noise Removal
• Slice Assembly
• TOPSAR Deburst and Merge
• GRD Border Noise Removal
• TOPSAR Interferometry
SNAP in a Nutshell
CATAPULT OPEN
New Level-2 OCN Visualisation
Credit: Sentinel-1 Toolbox – Open Source Tools for EOScience 2.0 @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
Polarimetric Tools
Quad Pol Decompositions• Sinclair • Pauli • Freeman-Durden • Van Zyl• Yamaguchi • Cloude • H/A Alpha • Touzi
Dual Pol Decomposition • H/A Alpha
SNAP in a Nutshell
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Quad Pol & Dual Pol Functionality
Credit: SNAP – The Sentinels Application Platform @ ESA EO SCIENCE 2.0 Workshop, 12-14 October 2015, ESA-Esrin, Frascati, Rome (Italy)
SNAP in a Nutshell
CATAPULT OPEN
The Product Library
• Convenient browsing and importing of products
having information and Quick Look product
• Now handles optical products and S-1 L2 OCN
products
SNAP in a Nutshell
CATAPULT OPEN
Processing Environment (in this course)
• Virtual Machine [4 cores (2 Ghz), 64 GB Ram], over Catapult cloud
computing commercial CEMS (Climate, Environment and Monitoring
from Space - CEMS)
• OS VM: Linux Ubuntu 14.04
N.B: Worldwind does not work sometimes om Linux and Mac OS.
• Snaphu (phase unwrapping) runs over Linux
Classification: OPEN
SNAP in a Nutshell
CEMS: Climate and Environmental Monitoring from Space
A purpose-built High Performance Cloud Computing facilities to provide:
• access to a wide range of Climate, Earth Observation (EO) and non-EO data;
• on demand, flexible, scalable and secure infrastructure for all communities
interested in working with satellite derived data and applications.
Classification: OPEN
SNAP in a Nutshell
Processing Environment (in this course)
• Guide to access the CEMS Commercial Cloud VM your desk
After logging in the VM:
• To launch SNAP GUI:
1. Double click over SNAP icon on the desktop
2. From Terminal: write command below into a terminal
sh /mnt/data/snapv2_20112015/bin/snap
• To launch the SNAP Graph Processing Tool (GPT) available only from terminal
Write command below into a terminal:
sh /mnt/data/snapv2_20112015/bin/gpt
SNAP in a Nutshell
CATAPULT OPEN
Customisation of “.snap” folder
By the default SNAP creates a folder named “.snap" during
the installation.
This folder contains internal configuration files (colour maps,
graphs etc.) and auxiliary files such as DEM, Orbits etc.
downloaded during the processing.
By default the .snap folder is created into:
• “home” directory (Linux-Mac)
• “C:\Users\user_name\” directory (Windows)
Because the ".snap" is starting with ".“, the folder is not always visible,
and also it is convenient having it in a partition where there is free space.
SNAP in a Nutshell
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Configuration of SNAP
Renaming and change the location for the .snap folder
Look for into the snap installation folder "../snap/etc/“
• Edit and modify into the “snap.properties” file the following:
snap.home=/mnt/data/snapv2_20112015/
snap.userdir=/mnt/data/logsnap
• Edit and modify into “../snap/etc/snap.conf” file (this for GPT):
default_userdir=/mnt/data/logsnap
Now the “.snap” folder is named “logsnap”
and it is located in: /mnt/data/logsnap
SNAP in a Nutshell
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SNAP interface
SNAP in a Nutshell
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SNAP interface: File
SNAP in a Nutshell
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SNAP interface: Edit
SNAP in a Nutshell
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SNAP Interface: Toolbars customisation
SNAP in a Nutshell
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SNAP Interface: Tool Windows
Worldwind requires OPEN GL library and it can
happen that some graphic card do not have it
or some version of Linux or Mac do not support
the application properly.
Use World map instead (click over it)
SNAP in a Nutshell
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SNAP Interface: Layer
SNAP in a Nutshell
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SNAP Interface: Vector
SNAP in a Nutshell
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SNAP Interface: Raster
SNAP in a Nutshell
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SNAP Interface: Optical
SNAP in a Nutshell
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SNAP Interface: Radar
SNAP in a Nutshell
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SNAP Interface: Tools
SNAP in a Nutshell
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SNAP Interface: Help
Any Question?