MERIS atmospheric correction effects using MEGS(c)

This tutorial builds upon the ESA ODESA (Optical Data Processor of the European Space Agency) project. More context information is available from the project web page.

Getting started

The Getting started guide to implement a "MERIS Level 1 to Level 2 atmospheric correction using MEGS(c)" application on Terradue's Developer Cloud Sandbox platform, a set of Cloud services to develop, test and exploit scalable, distributed Earth Science processors.

To run this application, you will need a Developer Cloud Sandbox that can be requested from Terradue's Portal, provided user registration approval.

Installation

Log on the developer sandbox and run these commands in a shell:

• Install Java 7

sudo yum install -y java-1.7.0-openjdk

• Select Java 7

sudo /usr/sbin/alternatives --config java

This will show on the terminal window:

There are 3 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
 + 1           /usr/java/jdk1.6.0_35/jre/bin/java
   2           /usr/lib/jvm/jre-1.5.0-gcj/bin/java
*  3           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java

Enter to keep the current selection[+], or type selection number:

Select java 1.7 out of the menu options by typing the correct number (here it's 3).

• Install this application

You can install the application in two ways, via mvn or via rpm

• install via mvn

Log on the developer sandbox and run these commands in a shell:

sudo yum -y install megs
git clone [email protected]:ocean-color-ac-challenge/megs-meris-ac.git
cd megs-meris-ac
mvn install

This will install the megs-meris-ac application and the megs processor from ESA.

• Download and install via rpm

Click on the latest release available in the releases page, then copy the file to your sandbox:

scp megs-meris-ac-0.1-ciop.noarch.rpm <your sandbox ip>:

Log on the developer sandbox and run this command in a shell:

sudo yum -y install megs-meris-ac

Submitting the workflow

Run this command in a shell:

ciop-simwf

Or invoke the Web Processing Service via the Sandbox dashboard providing a start/stop date in the format YYYY/MM/DD (e.g. 2012-04-01 and 2012-04-03) and a bounding box (upper left lat/lon, lower right lat/lon).

Using custom ADF

You can use ODESA to create a new set of ADFs.

Section 3.4.4 of the ODESA Quick Start Guide (ODESA-ACR-QSG issue 1.2.4 of March 5, 2012) shows how to edit the ADFs:

New ADFs created and modified by the user are placed in the working directory.

The general directory structure is as follows:

$WORKING_DIRECTORY/auxdatafiles/(processor_type)/(adf_format)/(adf_type)

For example a new ADF for the atmosphere products using the default name (atmosphere_copy.prd) would be found under:

$WORKING_DIRECTORY/auxdatafiles/megs/20/atmosphere_copy.prd

• Provide an compressed archive of the auxdatafiles folder with:

cd $WORKING_DIRECTORY
tar cvfz auxdatafiles.tgz auxdatafiles

Check here the typical content of $WORKING_DIRECTORY/auxdatafiles

• Upload the auxdatafiles.tgz archive to your sandbox with:

scp auxdatafiles.tgz <sandbox ip>:/tmp

• Invoke MEGS application:

  • via the WPS web interface with the parameter: file:///tmp/auxdatafiles.tgz
  • edit the application.xml and set the prdurl parameter value to file:///tmp/auxdatafiles.tgz; do a ciop-simwf

Community and Documentation

To learn more and find information go to

• Developer Cloud Sandbox service

Authors (alphabetically)

• Fabrice Brito
• Fabio D'Andria
• Samantha Lavender

License

Copyright 2014 Terradue Srl

Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0