How to get quantize values

问题

is there a way to get the start and end values of the quantizes of an quantize scale. The range is defined by 5 colors ans the domain by d3.min and d3.max function on my data from an json file. I need them for my legend of an choropleth map. Thank you for helping.

Carsten

Thats my code

var quantizecolors = ["#d7191c","#fdae61","#ffffbf", "#a6d96a","#1a9641"];
var colorEnerg = d3.scale.quantize().range(quantizecolors);
colorEnerg.domain([
                            d3.min(collection.features, function(d){return d.properties.EB/d.properties.BEVZ;}),
                            d3.max(collection.features, function(d){return d.properties.EB/d.properties.BEVZ;})
                            ]); 

回答1:

I assume that you're asking about the minimum and maximum domain values. Apart from saving them when you're setting them, you can also call colorEnerg.domain() without any values, which will return the array [min, max].

You can get the position of the breaks by computing the number and position of intervals:

var dom = colorEnerg.domain(),
    l = (dom[1] - dom[0])/colorEnerg.range().length,
    breaks = d3.range(0, colorEnerg.range().length).map(function(i) { return i * l; });

来源：https://stackoverflow.com/questions/20550840/how-to-get-quantize-values