将d3地理图块中的缩放限制为“最大" [英] Limit zoom to a 'maximum' in d3 geo tiles

问题描述

当您使用某些图块集(例如.tiles.mapbox.com/v3/mapbox.natural-earth-2/)时，应将d3地理图块的缩放限制为最大，否则这些图块不存在，无法找到，并最终显示难看的找不到" ' 背景图像.

When you use certain tile-sets (e.g. .tiles.mapbox.com/v3/mapbox.natural-earth-2/) the zoom on d3 geo tiles should be limited to a maximum, otherwise those tiles do not exist, cannot be found, and end up displaying an ugly 'cannot be found' background image.

我创建了小提琴(由用户Lex )向您展示我的意思.尝试单击一个小国家来复制该问题.该缩放级别不存在图块.以下两个解决方案是可以接受的.

I have created a fiddle (courtesy of user Lex) to show you exactly what I mean. Try clicking on a small country to replicate the issue. No tiles exist at that zoom level. The following two solutions would be acceptable.

1. 我将如何限制缩放功能clicked 计算缩放到边界框?
2. 如何修改脚本，以使功能clicked继续放大到可用的最详细的图块?

1. How would I set about limiting the zoom in function clicked that calculates the zoom-to-bounding-box?
2. How would I amend the script such that function clicked continues to zoom into the most detailed tile available?

推荐答案

一种简单的方法是通过设置最大缩放比例来限制缩放.

One easy approach to this is to limit the zoom by setting a maximum scaling factor.

例如在clicked中，您可以添加以下行:

For instance in clicked you could add a line like this:

scale = Math.min(1 << 14, scale);

(基于您之前的[1 << 11, 1 << 14]规模范围)

(based your previous scale extent of [1 << 11, 1 << 14])

这是更新的小提琴: https://jsfiddle.net/5Lf0w3sm/17/

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