地址：https://github.com/Leaflet/Leaflet/issues/6101，
看这个就行，按照这个说的做：
image.png
/*
* Workaround for 1px lines appearing in some browsers due to fractional transforms
* and resulting anti-aliasing.
* https://github.com/Leaflet/Leaflet/issues/3575
*/
(function(){
var originalInitTile = L.GridLayer.prototype._initTile
L.GridLayer.include({
_initTile: function (tile) {
originalInitTile.call(this, tile);
var tileSize = this.getTileSize();
tile.style.width = tileSize.x + 1 + 'px';
tile.style.height = tileSize.y + 1 + 'px';
}
});
})()
