Data Tools



Data Tools

Any GlobColour product (global products and local DDS) can be read and visualise thanks to a specific plug-in of the BEAM toolbox (see the Software section) so that any native function of the BEAM/VISAT package can be applied to the GlobColour data.

A number of statistical parameters is computed from the comparison of the DDS with either in-situ measurements (absolute validation) or other DDS used as reference, e.g. L2 binned products for the comparison between L3 merged products and data used as input of the merging algorithm. The following statistical results is computed:

  • Scatter plot of merged data versus the reference data set
  • Coefficient of determination: r2
  • Slope and intercept of the regression line
  • Mean ratio = Mean(merged data / reference data)
  • bias=Mean(data to be validated - reference data)
  • RMS= [Mean(merged data - reference data)2]
  • % difference= Mean(|merged data - reference data |/reference data)
  • Range of value for the reference and satellite data set

A comprehensive statistical analysis is conducted, and the results is analysed and reported used different clustering and subsets of data, as proposed hereafter:

  • by site (temporal variability)
  • by oceanic regions and along latitudinal transect
  • by water type (Case 1 & 2)
  • Global
  • Temporal variability
    • Daily and seasonal variability from PPS
    • Seasonal, inter-annual and long-term trend from FPS (stability over time: problem of quality consistency of in situ measurements)

All statistical analysis is conducted through BEAM.

The required functionalities is implemented as BEAM/VISAT plug-ins:

  • Loading of OC data (4 sensors) and DDS
  • Automation of exclusion criteria
  • Loading of in-situ datasets
  • Computations and display of statistics (mean ratio, correlation, regression, RMS, absolute accuracy, bias, range, )
    • between each OC data sources and in-situ data (main DDS sites)
    • between OC data sources (additional DDS sites)
  • Clustering of results.

For the absolute validation
Spatial validation: Globally, per ocean province, along a South-North transect Temporal validation: seasonal variability, inter-annual stability, temporal trend

For the relative validation
Globally, per ocean province, along a South-North transect (AMT transect), Northern Atlantic (Greenland Sea)



BEAM is the Basic ERS & Envisat (A)ATSR and MERIS Toolbox and is a collection of executable tools and an application programming interface (API) which have been developed to facilitate the utilisation, viewing and processing of data of various sensors. BEAM is also used for the validation of the GlobColour data in conjunction with the DDS Tools.

GlobColour BEAM/VISAT Reader

The GlobColour-Product-Readers module provides the capability of importing the binned and mapped GlobColour Level-3 data products into BEAM/VISAT. For installing the module, download the GlobColour-Product-Readers module and drop it into the modules directory of your BEAM 4.x installation. Note that the most recent module is always available through the VISAT Module Manager: Simply click on the Help entry in the main VISAT menu bar and select Module Manager... in order to open the Module Manager.

GlobColour Tools 1.4.7

The GlobColour Tools support the validation of the data products generated in GlobColour. The current set of tools are developed as plug-ins for BEAM 3.7. For installation refer to the README contained in the ZIP archive.

Export Pin-Pixels 1.3.1

This plug-in allows to export the pixel data of a rectangular region around all or the selected pin.

Other software


WIM is a general-purpose image display and analysis program for the Microsoft Windows operating systems with special features for analyzing satellite images.

  • Added functions to deal with GlobColour binned and mapped files. Section 20 in the WIM manual Wim.pdf has examples on using GlobColour global (FPS = Full Product Set) data that can be downloaded from FPS data access . Local datasets (DDS) for many diagnostic data sites are available from DDS data access.

  • Added a new WAM program wam_count that calculates a time series of the number of pixels with values either above or below a certain threshold. The time series can be produced for either whole images or for up to 255 specified areas of interest (masks).

GlobToolbox is a visualization tool that can be used for several products of the DUE Glob series. It provides easy access to large datasets, selected by geographic region and/or time frame. There is no need to know the file format and naming scheme of each product. Additional information can be found here.

The previewing features currently include:

  • colour table selection
  • coverage exporting to file
  • time series generation


The European Service for Ocean Colour - GlobColour is an ESA Data User Element Project