Exercise 5.1: Basic Supervised Classification
We will learn how to do a basic land cover classification using training samples collected from the Code Editor using the High Resolution basemap imagery provided by Google Maps. This method requires no prior training data and is quite effective to generate high quality classification samples anywhere in the world. The goal is to classify each source pixel into one of the following classes - urban, bare, water or vegetation. Using the drawing tools in the code editor, you create 4 new feature collection with points representing pixels of that class. Each feature collection has a property called with values of 0, 1, 2 or 3 indicating whether the feature collection represents urban, bare, water or vegetation respectively. We then train a Random Forest
classifier using these training set to build a model and apply it to all the pixels of the image to create a 4 class image.
Fun fact: The classifiers in Earth Engine API have names starting with smile - such as
ee.Classifier.smileRandomForest(). The smile part refers to the Statistical Machine Intelligence and Learning Engine (SMILE) JAVA
library which is used by Google Earth Engine to implement these algorithms.
Watch this video:
You can find the code of this exercise in the repository under Module5/Exercise1