Classifying data by manually altering the class breaks

Etapes :

1. Right-click the geostatistical layer that you want to manually classify in the ArcMap table of contents and click Properties.
2. Click the Symbology tab.
3. Click the Classify button.
4. Click the Method arrow and click Manual.
5. Click the up/down arrow of the Classes input box until the desired number of classes is reached.
6. Click and drag the class breaks to the desired position.

Alternatively, type in specific class breaks or set the Custom Min and Max control to True, then type specific minimum and maximum values to include in the classification.

7. Click OK on the Classification dialog box.
8. Click OK on the Symbology tab.