Change Detection

Nick Clinton, Earth Engine Developer Relations

nclinton@google.com

https://goo.gl/8q2MGm

Ladies and gentlemen, start your Earth Engines!

1. Get these slides: https://goo.gl/8q2MGm
2. Accept the Code Repo

Direct classification of change

Time 0 bands

Time t bands

…

classify()

Change categories

Post-classification comparison

Time 0

Time t

sample()

From

To

errorMatrix()

Index change

Time t

Time 0

Change

subtract()

Spectral distance

= p_t

= p₀

Distance = ||p_t - p₀||

Spectral angle

= p_t

= p₀

Angle =

acos( (p_t · p₀) / (||p_t||*||p₀||) )

Landscape metrics

Dominance = 1 - [ ∑_k(-P_klogP_k) / logK ]

​

Contagion = 1 - [ ∑_i ∑_k(-P_iklogP_ik) / 2logK ]

What changes will you detect?