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2. Classification land cover. Image classification uses multispectral digital numbers (colour')Most algorithms are per pixel' classifiers. 3. Classification. 4. Manual interpretation e.g. air photos. Human interpretation / classification relies on attributes such as:Shape, pattern, texture, shadows, size, association, tone, colour.
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1. 1 Remote sensing Classification
2. 2 Classification – land cover
3. 3 Classification
4. 4 Manual interpretation e.g. air photos
5. 5 Using just one band to classify ?
6. 6
7. 7 The role of multispectral sensing in classificationmultiple bands can be used as input
8. 8 The role of multispectral sensing in classification
9. 9 Band / channel selection controls success
10. 10 sample band correlation coefficients
11. 11 Classification: Band / Channel Selection
12. 12 Two main types of classification Unsupervised: the operator picks the algorithm and number of classes (clusters) … useful for a ‘quickie’ and with little or no ground info
Supervised: the operator picks the algorithm and designs the classes based on ground knowledge – takes longer, might be more accurate (!)
13. 13 A> Unsupervised classification
14. 14 Unsupervised result – 10 classes (clusters)
15. 15 B> Supervised classification
16. 16 Picking training areas – a good sample for each class
17. 17 Training areas (NASA training website)
18. 18 Supervised classification
19. 19 Supervised – class assignment
20. 20 Supervised classification methodsa. Minimum distance (below)b. Parallelepiped (right)c. Maximum likelihood (bottom right)
21. 21 Supervised classification: how it works
22. 22 comparison
23. 23 Relative points for the two methods
24. 24 End of classification part 1: Lab 3 on Mondaypart 2: tweaking it out