Center Color Ramp on Zero (or specified value)

05-23-2012 01:15 PM
Status: Open
Labels (1)
New Contributor II

When symbolizing classified quantitative data, it would be nice if you could control what class your color ramp "centers" on.

A specific example is that I have values above and below zero classified with equal intervals, ranging from about -10 to 45.  I want to use a two-color ramp (purples for negatives, oranges for positives) with the "neutral" mid-ramp yellow color applied to the class containing zeros.  By default (and there is no setting to change this!) the yellow gets applied to whatever class is in the middle, which works well if you have an equal number of classes above and below zero, but if you have more classes above zero than below, I would like to be able to specify which class gets the neutral color. 

Currently the only option is to create a custom color ramp.  But I am doing this over and over, with different ranges and with values in different proportions above and below zero, so I need a different custom ramp for each range. 


I have wished for the ability to do this for years! There is probably a way to do it using a histogram, but I've never figured it out.


I have an approach here that could be helpful, if you change all the zeros to whatever value you want to be centered on.  This was designed for a continuous (as opposed to discrete) color ramp. I agree it would be a lot better if this capability was built into Arc.