Lab 1 - Getting Started with GEE - Hello World

Objective: Get set up with Google Earth Engine and learn how to submit future labs.

What You'll Learn

  • Create and access your Google Earth Engine account
  • Navigate the Code Editor interface and understand its components
  • Write and run your first JavaScript program
  • Save scripts to your cloud repository
  • Share code via URL links for submission

Why This Matters

Google Earth Engine provides access to over 40+ years of satellite imagery and the computational power of Google's cloud infrastructure. Scientists use GEE to:

  • Monitor deforestation in the Amazon in near real-time
  • Track urban expansion across entire continents
  • Analyze crop health to improve food security
  • Map flood extent during natural disasters for emergency response

This first lab establishes the foundation for all future work in the course.

Before You Start

  • Prerequisites: Complete the Week 0 orientation materials and request access to Google Earth Engine with your institutional Google account.
  • Estimated time: 45 minutes
  • Materials: Google account credentials, access to your email for signup confirmation, and a notes document to record setup details.

Key Terms

Code Editor
The web-based IDE (Integrated Development Environment) where you write, run, and debug GEE scripts.
Console
The output panel where print() statements display their results and where errors appear.
Repository
A cloud-based folder that stores your scripts, similar to a folder on Google Drive.
Script
A file containing JavaScript code that Earth Engine can execute.

Introduction

In this course, we will use Earth Engine, and you will need to develop skills in both remote sensing and programming. The language of this course is JavaScript—a widely-used programming language that runs directly in your web browser.

Don't worry if you've never programmed before! We'll start with the basics and build up your skills gradually. By the end of this lab, you'll have written your first program.

Lab Instructions

  1. Step 1 - Sign Up for an Earth Engine Account

    Go to https://earthengine.google.com/

    Take a few minutes to explore the website and understand what Earth Engine offers.

    Click the Sign-Up page and fill out the form: https://signup.earthengine.google.com/

    Signup is typically approved within a few minutes to a few hours.

    Try It

    While waiting for approval, explore the Case Studies page to see real-world applications of Earth Engine.

  2. Step 2 - Access the Earth Engine Code Editor

    Once your account is approved, go to https://code.earthengine.google.com/

    The Code Editor is an integrated Earth Engine JavaScript API development environment. It offers an easy way to type, debug, run, and manage code.

    Screenshot of the GEE Code Editor interface
    The Google Earth Engine Code Editor Interface

    Take a moment to identify the main components of the interface:

    • Left Panel: Scripts (your saved code), Docs (API documentation), Assets (your data)
    • Center Panel: Code editor where you write JavaScript
    • Right Panel: Inspector (examine map), Console (view output), Tasks (exports)
    • Bottom Panel: Interactive map for visualizing results

  3. Step 3 - Writing Your First Code

    When learning a new language and programming environment, it is customary to create a program that displays the words "Hello World." This tradition dates back to the 1970s and helps verify that your environment is working correctly.

    Type the following code into line one of your script:

    print('Hello World');

    Understanding the code:

    • print - A built-in function that displays output to the Console
    • ( ) - Parentheses contain what you want to print
    • 'Hello World' - The text (string) to display, wrapped in quotes
    • ; - Semicolon marks the end of the statement

    Click the Run button. The output will appear in the Console tab on the upper right panel.

    Screenshot showing the Hello World console result
    Hello World output in the Console

    Expected Output

    Hello World

  4. Step 4 - Save Your Code

    Now let's save your script so you can access it later. Click the Save button.

    Save Button location in the Code Editor
    The Save button in the Code Editor

    If this is your first time using the Code Editor, you'll be prompted to create a home folder. This is your cloud storage location for all your code. Choose a name carefully— it cannot be changed later. A good choice is your Google Account username.

    Next, create a new repository (like a project folder). Repositories help you organize your code by topic or course. Name it "default" or "GEE_Course" to get started.

    Finally, save your script with the name "hello_world" and click OK.

    Save script dialog
    Saving your first script

    Your script now appears in the script manager panel on the left. Scripts are saved in the cloud and accessible from any computer.

  5. Step 5 - Share Your Code

    Click on the Get Link button to generate a shareable URL for your code.

    Get link button location
    The Get Link button allows you to share your code

    This URL contains your complete code and can be opened by anyone with a GEE account. This is how you will submit all future labs.

Check Your Understanding

  1. Where do you see the output when you run print('Hello World');?
  2. What are the three main panels in the Code Editor interface?
  3. Why do we need to put text inside quotes when using print()?
  4. What happens if you forget the semicolon at the end of your statement?

Answers: 1) Console tab (right panel), 2) Scripts/Docs/Assets (left), Code (center), Inspector/Console/Tasks (right), 3) Quotes indicate a text string vs. a variable or function, 4) GEE is forgiving—it often works, but it's best practice to include them.

Troubleshooting

Problem: Red text appears in the Console

Solution: This indicates an error. Check for typos—JavaScript is case-sensitive! Make sure print is lowercase and that quotes match (both single or both double).

Problem: Nothing happens when I click Run

Solution: Make sure you're logged into your Google account and that your Earth Engine access has been approved. Check that your code has been saved first.

Problem: Can't find the Get Link button

Solution: You must save your script first before the Get Link button becomes active. It's located in the toolbar area above the code editor.

Key Takeaways

  • print() displays output in the Console panel
  • Text strings must be wrapped in single quotes ' ' or double quotes " "
  • Scripts are saved in the cloud and can be accessed from anywhere
  • Use "Get Link" to create shareable URLs for code submission
  • The Code Editor has three main areas: Scripts (left), Code (center), and Console (right)

Pro Tips

  • You can also print numbers: try print(42);—no quotes needed for numbers!
  • Use Ctrl + Enter (Windows) or Cmd + Enter (Mac) to run scripts quickly
  • Click the "Docs" tab to search the API documentation whenever you're unsure about a function
  • Organize your scripts into repositories by topic (e.g., "Lab_Assignments", "Practice", "Projects")

📋 Lab Submission

Submit the URL of your GEE script via email.

Subject: Lab 1 - Getting Started - [Your Name]

Include in your email:

  • The shareable link to your "Hello World" script in Google Earth Engine
  • A screenshot of your Console output showing "Hello World"
  • Any questions or challenges you encountered

Next Steps

Congratulations on completing your first Earth Engine lab! You've taken the first step toward becoming proficient in cloud-based remote sensing analysis.

In the next lab, we'll explore how to load and visualize Landsat satellite imagery—you'll see Earth from space within your first few lines of code!

Continue to Lab 2 →