ESA Earth Home Missions Data Products Resources Applications
EO Data Access
How to Apply
How to Access
Reference documents
MERIS Product Handbook
MERIS Product Handbook
MERIS Product Handbook
MERIS Credits
MERIS Data Formats Products
MERIS Glossary and reference documents
Optics Glossary
Vegetation Glossary
Water Vapour Glossary
Ocean Colour Glossary
Neural Network Glossary
Meteorology Glossary
Cloud Glossary
Atmosphere Glossary
Product Glossary
Geometry Glossary
Acronyms and Abbreviations
MERIS Instrument
Instrument Characteristics and Performance
MERIS Quality Status
Instrument characteristic
Characterisation and Calibration
Onboard Calibration Hardware
Calibration Modes
Instrument Description
Instrument model philosophy
Instrument Concept
Digital processing Unit
Video Electronic Unit
Detection Focal Plane
Instrument optics
The MERIS instrument
MERIS Products and Algorithms
Auxiliary Files
Common Auxiliary Datasets
Auxiliary Datasets for Level 2 Processing
Auxiliary Datasets for Level 1b Processing
Summary of Auxiliary Datasets
Water Vapour Parameters Data File
Atmosphere Parameters Data File
Level 2 Control Parameters Data File
Aerosol Climatology Data File
Coastline/Land/Ocean Data File
Digital Roughness Model Data File
Radiometric Calibration Data File
MERIS Level 1b Control Parameters Data File
Digital Elevation Model
ECMWF Data Files
ENVISAT Orbit Data Files
Surface Confidence Map File
Land Vegetation Index Parameters Data File
Cloud Measurement Parameters Data File
Ocean II Parameters Data File
Ocean I Parameters Data File
Land Aerosols Parameters Data File
Ocean Aerosols Parameters Data File
MERIS Instrument Data File
MERIS-Specific Topics
Level 2 Products and Algorithms
Level 2 Products
Level 2 Geophysical Products
Annotation data set
Water Vapour products
Land products
Meris Terrestrial Chlorophyll Index
Meris Global Vegetation Index
Aerosol Angström Coefficient
Aerosol optical thickness
Cloud products
Cloud reflectance
Cloud Type
Cloud top pressure
Cloud albedo
Cloud optical thickness
Ocean products
The MERIS Aerosol Angström Coefficient
Aerosol optical thickness
Photosynthetically Active Radiation (PAR)
Yellow substance
Suspended matter
Algal Pigment Index II
Algal Pigment Index I
Normalized water leaving radiance / reflectance
Product description
Level 2 High-Level Organisation of Products
Full Resolution Geophysical Product
Extracted Vegetation Indices
Extracted Cloud Thickness and Water Vapour for Meteo Users
Extracted Cloud Thickness and Water Vapour
Reduced Resolution Geophysical Product
Level 2 Algorithms
Level 2 Accuracies
Level 2 Algorithm Description
MERIS Level 2 Product Formatting Algorithm
Measurement Data Sets
Annotation Data Set "Tie Points Location and corresponding Auxiliary Data"
Global Annotation Data Set - Scaling Factors
Annotation Data Set "Summary Product Quality"
Specific Product Header
Main Product Header
MERIS Land Pixels Processing
MERIS Bottom Of Atmosphere Vegetation Index (BOAVI) (step 2.8)
Atmospheric correction over land (step 2.6.23)
MERIS Top Of Atmosphere Vegetation Index (TOAVI) (step 2.2)
Water Processing
MERIS Ocean Colour Processing (step 2.9)
Clear water atmospheric corrections (step 2.6.9)
Turbid water screening and corrections (steps 2.6.8, 2.6.10)
Water Confidence Checks (step 2.6.5)
Cloud Processing
Cloud type processing (step 2.4.8)
Cloud Optical Thickness processing (step 2.4.3)
Cloud Albedo processing (step 2.4.1)
Total Water Vapour Retrieval
Water vapour polynomial (function)
Range checks (steps 2.3.0, 2.3.6)
Water vapour retrieval over clouds (step 2.3.3)
Water vapour retrieval over water surfaces (steps 2.3.2, 2.3.5)
Water vapour retrieval over land surfaces (step 2.3.1)
MERIS Pixel Identification
Land Identification (step 2.6.26) and Smile Effect Correction (step 2.1.6)
Gaseous absorption corrections (step 2.6.12)
Stratospheric Aerosol Correction (step 2.1.9)
Cloud screening (steps 2.1.2, 2.1.7, 2.1.8)
MERIS Pressure Processing
Atmospheric pressure confidence tests (steps 2.1.2)
Atmospheric pressure estimate (steps 2.1.5, 2.1.12)
MERIS Pre-processing
Pre processing step
Level 1b product check
Level 2 Physical Justification
Level 1b Products and Algorithms
Level 1b product definition
Browse Products
Level 1b Essential Product Confidence Data
Level 1b Engineering Quantities
Level 1b Accuracies
Level 1b High-Level Organisation of Products
Measurement Data Sets
Annotation Data Set "Product Quality"
Annotation Data Set "Tie Points Location and corresponding Auxiliary Data"
Global Annotation Data Set
Specific Product Header
Main Product Header
Full Resolution Geolocated and Calibration TOA Radiance
Reduced Resolution Geolocated and Calibration TOA Radiance
Level 1b Algorithms
External Data Assimilation
Pixel Classification
Stray Light Correction
Radiometric Processing
Saturated Pixels
Source Data Packet Extraction
Level 0 Products
Product Evolution History
Definitions and Conventions
Notations and Conventions
Product Grid
Organisation of Products
MERIS product data structure
File naming convention
Acquisition identification scheme
Product identification scheme
Latency, Throughput and Data Volume
MERIS products overview
MERIS product types
Full and reduced resolutions
MERIS product processing levels
MERIS User Guide
Image gallery
How to Use MERIS Data
Software Tools
General Tools
How to Choose MERIS Data
Summary of Applications vs. Products
Special Features of MERIS
Geographical Coverage
Principles of Measurement
Scientific Background
Mission Objectives
MERIS Level 3 products
Geophysical Measurements
MERIS Product Handbook
Site Map
Frequently asked questions
Terms of use
Contact us


2.3.2 Product Grid

MERIS is an imaging instrument that produces three-dimensional data sets. The first dimension corresponds to the lines that follow the along-track chronological order - the number of lines is always product-dependent. The second dimension corresponds to the columns of the image; in the Level 0 image columns correspond to the across-track instrument pixels, and in the Level 1b or Level 2 images columns correspond to the across-track product earth pixels. The third and last dimension corresponds to the different geophysical parameters that are produced from a MERIS image.

The MERIS Product grid is intended to:

· be related to the satellite track (assuming nominal pitch and yaw attitude control of the satellite)

· provide quasi-even distance sampling of the parameters on Earth

· provide geolocation and other geophysical annotations as a regular subset of the pixels in order to improve storage efficiency

Resampling is defined on a line basis, with an even spacing grid on Earth with regard to the geoid surface in the across-track direction, it is centred at the subsatellite point as known from orbit prediction, nominal attitude control and modelled attitude perturbations. The along-track sampling is evenly spaced in time and thus provides a quasi-even distance on Earth; possible variations of the along-track sampling step may be due to the orbital motions of the satellite and/or to the ellipsoidal shape of the Earth.

There are different grids used in the MERIS processing, which are summarised below:

· The tie points grid is identical for all products. It has 71 tie points across-track, it is a 16 x 16 sub-grid of the RR product grid, a 64 x 64 sub-grid of the FR product grid, and a 4 x 4 sub-grid of the Browse and LR product grids. Image location and geometrical annotations are only provided at tie points.

· The Reduced-Resolution product grid has 1,121 RR pixels across-track.

· The Full-Resolution product grid has 4 x 4 more points than the RR product grid, in the across-track direction it has 4,481 points.

· The Browse product is obtained by sub-sampling a Level 1b product.

For the various resolutions, the across-track (at nadir) and the along-track distances between two points are shown in table 2.4 :

Table 2.5 - Across-track and along-track distances.

AC distance at Nadir (m)

AL distance (m)

Low Resolution



Reduced Resolution



Full Resolution (scene or imagette)



Figure 2.4 - Column and frame index.

The MERIS convention used for indexing column and lines is as follows. Column numbering starts at 1 and increases from east to west, and line numbering starts at 1 and increases from north to south.

The standard tools (BEAM, EnviView…) process and display the image in classical Earth representations.

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry