传单测量转换的准确性 [英] Preciseness of leaflet measurement conversions

问题描述

map.layerPointToLatLng(map.latLngToLayerPoint(L.latLng(40.687, -73.9035)))

产生

{lat:40.686886382151116，lng:-73.90228271484375}

{lat: 40.686886382151116, lng: -73.90228271484375}

不精确度似乎过高，尤其是对于经度.

The imprecizeness seems to be unreasonably high, especially for the longitude.

map.getZoom()

产生

9

map.getSize()

产生

{x:1335，y:430}

{x: 1335, y: 430}

有没有提高精确度的方法?

Is there a way to increase preciseness?

推荐答案

如果我正确理解，则首先将LatLng转换为当前地图视图(缩放比例为9，无论视图的端口尺寸如何)上的像素位置.

If I understand correctly, you first convert your LatLng to a pixel position on your current map view (zoom 9, whatever view port dimensions).

然后，您将该像素位置转换回LatLng，并注意到与原始LatLng不一致.

Then you convert that pixel position back to a LatLng, and notice a discrepancy with your original LatLng.

在我看来，您只是观察像素舍入的效果: map.latLngToLayerPoint 将为您提供整数像素坐标，因此就实际距离而言，您的精度不会比像素覆盖的精度好.

It seems to me that you simply observe the effect of pixel rounding: map.latLngToLayerPoint will give you integer pixel coordinates, hence your precision will be no better than what a pixel covers in terms of actual distance.

在9缩放和纽约纬度(40.687)下，比例为86px约为20公里，因此每个像素约为230m.

At zoom 9 and New York latitude (40.687), the scale is about 20km for 86px, so about 230m per pixel.

您报告的2个LatLng坐标之间的距离约为103m.因此，它恰好在单个像素内.

The distance between the 2 LatLng coordinates you report is about 103m. Therefore it is well within a single pixel.

实时演示: https://jsfiddle.net/3v7hd2vx/149/(结果是在控制台中打印)

Live demo: https://jsfiddle.net/3v7hd2vx/149/ (results are printed in the console)

您可以使用地图缩放来查看精度的提高，因为每个像素将覆盖更小的距离(实际上是区域).

You can play with map zoom to see the precision improving, as each pixel will cover a smaller distance (area actually).

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