Google
1 of 9
Change Detection
Nick Clinton, Earth Engine Developer Relations
2 of 9
Ladies and gentlemen, start your Earth Engines!
- Get these slides: https://goo.gl/8q2MGm
- Accept the Code Repo
3 of 9
Direct classification of change
Time 0 bands
Time t bands
…
classify()
Change categories
4 of 9
Post-classification comparison
Time 0
Time t
sample()
| |
c 1 |
c 2 |
c 3 |
| c 1 |
|
|
|
| c 2 |
|
|
|
| c 3 |
|
|
|
From
To
errorMatrix()
5 of 9
Index change
Time t
Time 0
Change
subtract()
6 of 9
Spectral distance
= p t
= p 0
Distance = || p t - p 0 ||
7 of 9
Spectral angle
= p t
= p 0
Angle =
acos( ( p t · p 0 ) / (|| p t || * || p 0 ||) )
8 of 9
Landscape metrics
Dominance = 1 - [ ∑ k (- P k log P k ) / log K ]
Contagion = 1 - [ ∑ i ∑ k (- P ik log P ik ) / 2log K ]
9 of 9
What changes will you detect?
