Overview

GSDView is the acronym of Geo-Spatial Data Viewer. Its original purpose was to provide a simple tool for handy visualization of EO data and attached ancillary information (from now on metadata). Common imaging SW are not able to display EO products because of their particular and very specific format and because EO products are usually very large in terms of disk/memory size.

Two editions of GSDView currently exist:

• an open source version named GSDView Open Edition that is freely available and provides only very basic features.
• a GSDView Pro Edition [1] that is more complete and provides image analysis tools and ready to use integration components for image processing tools exploitation. GSDView Pro is currently one of the few SW products that support products of the COSMO-SkyMed mission.

See also

Features map for more details.

GSDView is written in python and Qt4.

Footnotes

[1]	GSDView Pro Edition has been developed by INNOVA

SAR WorkBench

GSDView Pro is the GUI component of SAR WorkBench 2 (SWB2), a flexible and extensible framework (currently under development) for multi-mission EO data visualization, analysis and post-processing.

It is modular and has a plug-in architecture (see SWB2 Software Architecture) that makes it very flexible.

The main functional areas are:

• the GUI (GSDView Pro)
• Ingestion/data exchange
• QA (Quality Analysis)
• Data processing

All the framework is based on the abstract data model provided by the GDAL library.

Thanks to GDAL and some especially developed extensions, SWB2 is able to manage EO products from a large variety of SAR missions: COSMO-SkyMed, TerraSAR-X, Radarsat 1/2, ALOS/PALSAR, ERS 1/2, and ENVISAT.

It can also handle optical data such as the ones from ENVISAT/MERIS sensor and ALOS/AVNIR-2.

The desktop application

The SWB2 framework is deployed as a desktop application whose graphical front-end is GSDView.

The GSDView main window

The viewer has been designed to be extremely user-friendly.

It provides a dataset browser listing all open products, a main visualization area, a metadata viewer and a panel indicating the geographical location of the image on a world map (Fig. The GSDView main window).

Once a particular product is selected and visualized, the user can select a specific area of interest of the image and stretch it to further analyse it, as shown in Fig. The GSDView main window, where a section of a SAR image of the Palm islands near Dubai (United Arab Emirates) has been enlarged.

The viewer provides common functionalities such as:

• zoom,
• stretching (pixels value scaling),
• scroll,
• pan
• displaying multiple datasets opened at the same time (MDI)
• modifying application settings through a user-friendly GUI
• displaying product metadata

Through the GUI interface the user can access all the other modules available in SWB2.

Further to allowing access to multi-mission data, the ingestion and data exchange sub-system also enables the user to export data into standard graphic formats (GeoTIFF, JPEG, PNG) compatible with wide spread software tools and in formats specific for the main GIS and EO applications.

This is fundamental for the integration of SWB into scientific and production environments.

The Quality analysis plug-in includes tools for the measurement of IRF parameters such as geometric resolution, PSLR, SSLR, ISLR and IRF shape and tools for statistics and radiometric analysis.

The Data processing modules provide a set of command line tools and processors that are specific for SAR data processing.

Base functions include filtering, re-sampling, complex data detection without aliasing, geo-coding and ortho-rectification.

More advanced functions such as co-registration and interferometric processing are planned or available via external tools.

In addition to the GDAL library, SWB2 also uses the powerful processing library OTB.

Processing tools (command line) are integrated in the GUI application that is able to drive them an also provides simple configuration dialogs.

SWB2 Software Architecture

High level SWB2 architecture

SWB2 is developed in the open-source philosophy. It is modular and has a simple plug-in architecture. Figure High level SWB2 architecture shows the high-level system architecture of SWB2 and identifies the main components of the software:

• GSDView: the graphic component which is used to control the rest of the system

• ProcTools: command line tools (mainly based on the OTB library) for efficient data processing

• A set of libraries including external open-source libraries like GDAL and OTB, and auxiliary libraries developed by INNOVA specifically for the application. From a logical point of view the libraries layer can be split as follows:

  • libraries for I/O and geospatial products management: including GDAL, the OTBIO module and some extensions developed by INNOVA specifically for the project.

    These extensions also enable the program to access COSMO-SkyMed data.

  • processing libraries: mainly based on OTB (at the moment) this set of libraries provides both processing functions (including specific ones for SAR data processing), and an infrastructure for blocks processing (streaming) and parallel processing (threading)

Document summary

The GSDView Pro User Manual has this structure:

1. Chapter Overview: brief description of GSDView
2. Chapter Installation: GSDView installation procedures for Windows and GNU/Linux platforms
3. Chapter The Graphical User Interface: describes the user interface (GUI)
4. Chapter Processing tools: provides datails abiìout available processing tools
5. Chapter Quality analysis plug-in: describes tools for geometric and radiometric analysis
6. Chapter Tutorials: contains some easy tutorial for beginners
7. Chapter Supported formats: lists the product formats supported by the tool
8. Chapter Features map: table for the functionality development for open and pro version
9. Chapter Change history: describes changes from one release to another
10. Chapter Glossary: description of the terms used in this document