The goal is to style a polygon layer using graduated colors, something like

-9999 < value < 0 --> some color
0 =< value < 0.1 --> some other color
0.1 =< value 0.2 --> some other color

However, for some reason the number of classes is grayed out.

enter image description here

and when I click on classify:

enter image description here

classes is still grayed out.

Any thoughts?

ArcMap 10.5, the datalayer is using a join of a shapefile and csv table.

Number of classes is 7 and colors are custom (cannot be generated by colorbar).

1 Answer 1


Change the classification method to something different (e.g. equal interval). Classes is no longer greyed out. Then change the number of class levels to what you require, and then change the method back to 'Manual'.

  • very odd, is this a bug?
    – RutgerH
    Aug 6, 2018 at 14:18
  • 1
    Good question; I'd say it's a 'feature'. I've been using the workaround for well over 10 years so I guess it's something one gets used to (or perhaps inured to!).
    – JimT
    Aug 6, 2018 at 14:36
  • this feature keeps drawing me to arcmap, this is amazing! thanks
    – RutgerH
    Aug 6, 2018 at 15:51

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