如何计算量表的结果? [英] How to calculate the scale's result?

问题描述

我是d3.js库的新手，我试图了解域和范围的概念.

I am new to d3.js library, and I am trying to understand the concept of domain and ranges.

我阅读了斯科特·默里(Scott Murray)的书，但我没有不知道如何计算.

I read Scott Murray's book, but I don't know how to calculate it.

我有这个:

var scale = d3.scale.linear()
    .domain([100, 500])
    .range([10, 350]);

scale(100);  //Returns 10
scale(300);  //Returns 180
scale(500);  //Returns 350

我知道我的输入中有100个单位代表我的输出中有10个，而对于500和350来说却是相同的...但是为什么对于300作为输入返回180?我该如何计算这个值?

I know that 100 units of my input represent 10 in my output, and the same with 500 and 350... but why 180 is returned for 300 as input? How can I calculate this value?

我也阅读了本教程，它解释了如何计算它，但是当我遵循时该方法，我没有得到相同的值，即scale(300)不返回180.

I read this tutorial too, which explains how to calculate it, but when I follow the method, I don't get the same value, i.e., scale(300) doesn't return 180.

知道为什么吗?

推荐答案

是的，我将尝试解释您为什么要达到180.

Yes I will try to explain why you get 180.

我们拥有300的值，可以理想地将您的域划分为两个相同大小的子域，因此我们可以执行以下操作: 500 - 100 / 2 = 200(这是子域的大小)， 这意味着中间值位于:
200 + 100 = 300(请注意，我们添加了起点100)

We have that 300 is the value that ideally divide your domain into two subdomains of the same size, so we can do: 500 - 100 / 2 = 200 (this is the subdomain size), this implies that the middle value is located at:
200 + 100 = 300 (note that we add the starting point 100)

因此在范围内，我们将执行相同操作:
350 - 10 / 2 = 170 然后我们添加起点 170 + 10 = 180

So with the range we do the same:
350 - 10 / 2 = 170 and then we add the starting point 170 + 10 = 180

这篇关于如何计算量表的结果?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！