将图块的xyz坐标转换为经度/纬度

Question

I wanted to make a map using openlayers but center it a unique way. For example I have az/x/y coordinate of 12/2045/-1362, how do I convert it to longitude/latitude? It's quite the polar opposite of this: How to get XYZ coordinates of tile by click on Leaflet map

It's quite hard for me to get the logic of the above link and invert it. I hope someone here has an experience or a ready-made formula for this. Thanks

Later I'll this in rendering the center of my map like this:

var z = 12;
var x = 2045;
var y = -1362;

function convertXYZtoCoor(z, x, y) {
    // code here
    return [lng, lat];
}

var coor = convertXYZtoCoor(z, x, y);
var view = new ol.View({
                    center: ol.proj.transform(
                        [coor[0], coor[1]], 'EPSG:4326', 'EPSG:3857'),
                    zoom: z
            });

var map = new ol.Map({
                layers: [
                    new ol.layer.Tile({
                        source: new ol.source.OSM()
                    })
                ],
                target: 'map',
                view: view
          });

Hope my question is understood more thanks.

Edit: Added code

Answer 1

var tileExtent = function(tileCoord){
    var z = tileCoord[0];
    var x = tileCoord[1];
    var y = tileCoord[2];
    var tileGridOrigin = tileGrid.getOrigin(z);
    var tileSizeAtResolution = tileGrid.getTileSize(z) * tileGrid.getResolution(z);
    return [
        tileGridOrigin[0] + tileSizeAtResolution * x,
        tileGridOrigin[1] + tileSizeAtResolution * y,
        tileGridOrigin[0] + tileSizeAtResolution * (x + 1),
        tileGridOrigin[1] + tileSizeAtResolution * (y + 1)
    ];
}

You can test/verify at http://jsfiddle.net/eurx57s7/

Note (stolen from the ol3 example, but it applies here to): The tile coordinates are ol3 normalized tile coordinates (origin bottom left), not OSM tile coordinates (origin top left)