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Show 0 value on map of diverging data

March 23 2011 | 0 comments
Categories: Symbology

I have a set of maps I produce each week of a data represented with diverging colors. The symbology breaks are centered around 0 and I want to show 0 as its own color, not mixed into other classes. I know I can add a range of -.01 to .01 or something similar but If I don't have to I would rather not.

Mapping Center Answer:

Graduated colors classes are defined by class breaks. The breaks are actually the upper limit for each class. The lower limit of a class is not explicitly set; it just includes anything above the upper limit of the class below it. So there is not a way to set classes such that it only includes one value like zero. In this example you would have to set the class for the lower value to be as close to zero as you need it to be to make sure it includes every possible value short of zero, then set the class break for the "zero" class to zero. Then you can edit the label in the Layer Symbology dialog to only show 0.

Another way would be to include 3 copies of the layer, one for values below zero (symbolized with one set of sequential colors), one for zero (symbolized with the color for zero only), and one for values above zero (symbolized with another set of sequential colors). Then use definition queries to only show the appropriate subset of features for each of the three layers.

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