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Contribute to Custom Scripts

Have a look at the template for an example of how a script page can be structured.

There is also an example for a page with can display multiple scripts.

You can also have a look at other scripts to see how they are structured.

For instructions on how custom scripts are structured have a look at this tutorial, or at the official documenation.

How to publish your own product

  • Fork the repository to get your own copy of the custom-scripts
    It is easiest to fork the repository on GitHub, but as some of you might not have GitHub account, or don’t want to bother with all this versioning and collaboration tools, you can also just download the whole repository as Zip file and work from there.
  • Create a new directory entry for your custom script
    Copy the example directory to proper directory, based on which datasource (satellite) you are publishing the product for, to something that describes what the product is about, say my_algorithm.
    Preferably use “snake_case” (underscores instead of spaces) if more than one word is used.
  • Fill in the details about the project in the file.
    Obviously, you’ll want to remove this chapter, but use the rest of the file as a template.
    Have a look around at other files to see how to include images, format the text and generally use the GitHub markdown (e.g. here for mathematical formulas or here for adding images).
  • Implement the product in the script.js file.
    The most work is of course the JavaScript implementation of the product. The example folder includes an empty custom script with comments that will hopefully help you build your own custom script.
  • Add an entry pointing to your script to the top level markdown file (i.e. if adding a script for Sentinel 2 add the link to in the folder sentinel-2).
    A link and a short description will do.
  • And create a pull request :).
    There is extensive help on creating pull requests on GitHub help, but if you feel overwhelmed by this step and would still like to contribute, send us the folder you’ve created and we will take care of it for you.

Publishing your product should be easy, nevertheless, any feedback and ideas how to improve or make the process simpler is very appreciated.

Test your changes locally

This is optional but makes Pull Requests quicker to handle since they should have less mistakes.
Before you create the PR you can check if everything looks right on the website. To do this follow these steps which are based on Testing your GitHub Pages site locally with Jekyll page:


  • In the root directory of your fork open a terminal
  • Install ruby
    • Ubuntu: sudo apt install ruby ruby-dev
  • Install bundler
    • gem install bundler
    • On Ubuntu you might have to add sudo
  • Create a Gemfile
    • In the root folder of the repository (where the _config.yml file is) create a new file Gemfile.
    • i.e touch Gemfile
    • and add the following content:
source ''
gem "github-pages", "~> GH_VERSION", group: :jekyll_plugins
gem "just-the-docs"

Replace GH_VERSION with the version number that is displayed next to github-pages here.

  • Serve the page
    • First install all necessary gems with bundle install
    • then the site can be built with bundle exec jekyll serve
    • The site should then be visible on


  • In the root directory of your fork open a terminal
  • Install ruby

    • brew install chruby ruby-install xz

      • If homebrew hasn’t been installed yet, intall homebrew
      /bin/bash -c "$(curl -fsSL"
    • ruby-install ruby 3.1.3
    • After installation run the following codes:
    echo "source $(brew --prefix)/opt/chruby/share/chruby/" >> ~/.zshrc
    echo "source $(brew --prefix)/opt/chruby/share/chruby/" >> ~/.zshrc
    echo "chruby ruby-3.1.3" >> ~/.zshrc # run 'chruby' to see actual version
    • Quit and relaunch Terminal, then check that everything with ruby -v
    • It should show ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) or a newer version
  • Install Jekyll
    • gem install jekyll
  • Install bundler
    • gem install bundler
  • Following the Create a Gemfile step in the Linux section
  • Serve the page

    • First install all necessary gems with bundle install
    • Add the missing webrick package with bundle add webrick

      • Run this command again when the following error message pops out:
      bundler: failed to load command: jekyll
    • then the site can be built with bundle exec jekyll serve
    • The site should then be visible on


  • First of all, you will have to have Git installed on your system. In a command terminal, type git version. If you get a version number, you have Git installed. Otherwise, follow the instructions here
  • You will mainly want to follow this installation guide:
    • Go to Ruby, download windows installer, eg from here
      • Run the installer file to install ruby
      • Once the installer is ready, you can check Ruby by opening a terminal and typing ruby -v . A version number should be displayed.
    • Install bundler
      • In the terminal, type gem install bundler
  • If you get an error message “Cannot create directory, filename too long”, you have to enable long file paths for Git on your system. Open a command prompt, running it as an administrator.
  • Then type git config --system core.longpaths true

  • Assuming Git is already installed on your system, now you can clone the repository to a folder on your computer (if you haven’t already):
    • Navigate to the parent folder, right-click and select “Git GUI Here”, and type git clone
  • Now you are ready to set up jekyll. Navigate to the main folder of the cloned repository (“custom-scripts”)
  • Type bundle install and wait for the process to finish
  • Now type bundle exec jekyll serve and wait for the local server to generate (“generating…”). You will see the message with the address of the local server, eg. “Server address :”
    • Copy this address to a web browser, and you will see the web version of the custom script repository, but with all of your local changes included. This will allow you to test layouts and the effects of your changes. If you make a change to a file you are displaying in Jekyll, save it and wait for the regenerating process to run. You will see the message in the Git GUI window: ‘Regenerating: 1 file(s) changed … done in XX seconds` If everything looks OK, you can commit, push and create a pull request.