Google Earth Engine

Welcome to Maptime Seattle!

Maptime is a community dedicated to teaching and learning all things geospatial. Maptime offers local mappers the opportunity to learn cutting-edge geospatial technologies.

Maptime’s mission is :

"to open the doors of cartographic possibility to anyone
interested by creating a time and space for collaborative
learning, exploration, and map creation using mapping tools
and technologies."

Introduction

Earth Engine is a planetary-scale platform for Earth science data & analysis

Remote Sensing Archives

petabytes of data located on Google servers
you don’t need to download or extract any data!

Distributed computational power

CPU clusters provided / limits managed by Google

Server-side programming

data is stored in the cloud

We are going to use the Code Editor which presents a simple access point to learning the Earth Engine platform. The Code Editor utilizes the Earth Engine JavaScript API to run scripts and functions to interact with Earth Engine-hosted data.

Earth Engine is not just another JavaScript library.

In fact Earth Engine also has a Python API which is better-suited for building applications. Today, we want to help you get started with Earth Engine by exploring some of the basic functionality. If you don’t know JavaScript or any coding for that matter, don’t worry. We’ll walk you through what you need to know.

Why use Earth Engine? Because you can! It is powerful allowing you, the analyst/developer, to bring code to the data, which shortens the process of doing exploratory data analysis.

Datasets

Satellite Imagery Datasets:

Landsat Archives (4, 5, 7, 8)
MODIS
Sentinel 1, 2

Climate Datasets

Precipitation
Sea Surface Temperature
Ozone

APIs

JavaScript and Python APIs

A few Earth Engine JavaScript API terms:

variable: stored thing in memory

function: stored operation

asset: geospatial data; e.g. Feature, FeatureCollection / Image, ImageCollection

band: remotely-sensed data stores measured reflectance for different wavelength ranges in separate bands though the spatial resolution and capture time are the same; e.g. Images are composed of bands

reducer: a function which is mapped over all pixels in an Image or ImageCollection: e.g. mean(), median()

By the time we finish this tutorial, you will have the basics to start exploring data with Earth Engine.

Tutorial Time!

What do I need for this tutorial?

If you don’t yet have one, please create a Google account: https://goo.gl/KmaV3j
Sign up for an Earth Engine account using your gmail account: https://goo.gl/qJgvcP
Open an Incognito window of Chrome
Join the MaptimeSEA Earth Engine 101 Google Group with your gmail account: https://goo.gl/TEPFbt
Accept this shared code repository named maptimesea_earthengine101: https://goo.gl/g6xxTT

Tips

The learning curve can be pretty steep. Stay positive. Ask lots of questions.
Start simple, add complexity piece by piece
Cannibalize code wherever/whenever you can. The Earth Engine Developer Forum has great examples and includes a lot of code.

What can be done with Earth Engine?

Check out these examples of Earth Engine visualizations and applications: Case Studies

Fin.

Hope that was helpful! Please fill out our survey when you are done even if you couldn’t attend the meeting. We want to make sure the MaptimeSEA tutorials are teaching what you want to learn. bit.ly/maptimesea_survey