需要使用d3 geoPath.projection缩放已投影的数据（null） [英] Need to scale already projected data using d3 geoPath.projection(null)

问题描述

基于d3（ver 1.4）文档 https：/ /github.com/d3/d3-geo/blob/master/README.md#geoProjection ，应将d3投影设置为null以使用数据的原始坐标。如果投影看起来正确使用null，我该如何缩放？以下是代码：

Based on d3 (ver 1.4) documentation https://github.com/d3/d3-geo/blob/master/README.md#geoProjection , the d3 projection should be set to null to use the data's raw coordinates. How do I scale if the projection looks correct using null? Here is the code:

var path = d3.geoPath()
    .projection(null)
    .context(context);

bands.features.forEach(function(d, i) {
  context.beginPath();
  context.fillStyle = colors[i];
  context.globalAlpha = .5;
  path(d);
  context.fill();
});

我尝试定义自己的投影，但投影看起来不正确。这是代码

I have tried defining my own projection but the projection looks incorrect. Here is the code

var project = d3.geoProjection(function(x,y){
    return [x,y]
});

var path = d3.geoPath()
    .projection(project)
    .context(context);

推荐答案

感谢您的建议。我的问题结果不是规模问题，而是矩阵转换问题。我正在使用d3marchingsquares.isobands软件，我需要在将数据发送到行进方格之前转置我的数据。

Thanks for your suggestion. My problem turned out to not be a scale problem but a matrix transformation issue. I am using the d3marchingsquares.isobands software and I needed to transpose my data prior to sending it into marching squares.

我的项目创建一个类似于 https://earth.nullschool.net/ 但使用谷歌地图。

My project is create a map similar to https://earth.nullschool.net/ but using Google Maps.

我正在调整Roger Veciana的带有d3的geotiff的isobands演示 http://bl.ocks.org/rveciana/de0bd586eafd7fcdfe29227ccbdcd511 。这几乎已经完成但是在调整画布层大小时出现问题。接下来，我将把Danny Cochran的可卷绕帆布层覆盖在温度轮廓上。我更新了Danny Cochran的代码，以使用最新的Google Map版本。

I am adapting Roger Veciana's "Isobands from a geotiff with d3" demo http://bl.ocks.org/rveciana/de0bd586eafd7fcdfe29227ccbdcd511. This is almost complete but having issues resizing the canvas layer. Next I am going to overlay Danny Cochran's windable canvas layer over the temperature contours. I updated Danny Cochran's code to work with the latest Google Map's version.

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