1. Introduction

2. Fisher discriminant method
2.1. Principle
2.2. Application to ELGs

3. Data
3.1. Photometry
3.2. Fisher training sample
3.3. Spectroscopic verification sample

4. Improvement with using the WISE/W1 data

5. ELG selection with Fisher discriminant
5.1. Why use a Fisher discriminant approach?
5.2. Fisher selection schemes
5.3. Colour-colour cut selections
5.4. Selection properties
5.5. Adjusting the selection density

6. Fisher UGRIZW1 and Fisher GRIW1 selection stacked properties
6.1. Stacked spectra
6.2. Stacked CFHTLS-Wide image

7. Conclusions