mapbox实现线条阴影

在Mapbox中实现线条阴影，可以通过添加一个带有半透明颜色的描边来实现。具体步骤如下：

在地图样式中，将线条的描边颜色设置为半透明的黑色，例如rgba(0, 0, 0, 0.2)：

"paint": {
  "line-color": "#ffffff",
  "line-width": 3,
  "line-opacity": 1,
  "line-translate": [0, 0],
  "line-translate-anchor": "map",
  "line-gap-width": 0,
  "line-offset": 0,
  "line-blur": 15,
  "line-dasharray": [],
  "line-pattern": "",
  "line-gradient": "",
  "line-stroke-width": 1,
  "line-stroke-opacity": 0.2,  // 设置描边透明度为0.2
  "line-stroke-color": "#000000"  // 设置描边颜色为黑色
}

将线条的填充颜色设置为透明，这样描边就会成为线条的阴影：

"paint": {
  "line-color": "#ffffff",
  "line-width": 3,
  "line-opacity": 1,
  "line-translate": [0, 0],
  "line-translate-anchor": "map",
  "line-gap-width": 0,
  "line-offset": 0,
  "line-blur": 15,
  "line-dasharray": [],
  "line-pattern": "",
  "line-gradient": "",
  "line-stroke-width": 1,
  "line-stroke-opacity": 0.2,
  "line-stroke-color": "#000000",
  "line-fill-opacity": 0  // 设置填充透明度为0
}

这样就可以在Mapbox中实现线条阴影了。可以根据需要调整描边的透明度和颜色，以及线条的宽度和模糊程度来达到不同的效果。