OL5 VectorTileLayer: Y coordinate of tile

Question

I try to use OL5 vector tiles with global tile grid.

import 'ol/ol.css'
import { Map, View } from 'ol'
import MVT from 'ol/format/MVT'
import TileGrid from 'ol/tilegrid/TileGrid'
import VectorTileLayer from 'ol/layer/VectorTile'
import VectorTileSource from 'ol/source/VectorTile'

let zoom = 0
let center = [8531000, 5342500]
let resolutions = [
    9.554628535647032,
    4.777314267823516,
    2.388657133911758,
    1.19432856695588,
]
let extent = [0, 0, 20037508.342789244, 20037508.342789244]

const map = new Map({
    target: 'map',
    view: new View({
        zoom: zoom,    
        center: center,
        resolutions: resolutions,
   })     
})

const vectorTiles = new VectorTileLayer({
    source: new VectorTileSource({
        tileSize: 256,
        projection: 'EPSG:3857',
        format: new MVT(),    
        tileGrid: new TileGrid({      
            extent: extent,          
            resolutions: resolutions,
        }),    
        url: 'http://localhost:8000/get-vector-tiles/{z}/{x}/{y}'
    })   
 })

 map.addLayer(vectorTiles)

A request looks like http://localhost:8000/get-vector-tiles/0/3487/6007, as I understand {x}/{y} are coordinates(numbers) of a tile from origin(in my case 0,0).

The start resolution is 9.554628535647032, therefore a tile size is 9.554628535647032 × 256 = 2445.984905126 meters

Estimating of requested area coordinates:

X: 2445.984905126 × 3487 = 8529149.3642

Y: 2445.984905126 × 6007 = 14693031.2943

Considering the center of map is [8531000, 5342500]:

X coordinate is right 8529149.3642 ~ 8531000, while Y coordinate does not match 5342500 vs 14693031.2943

What's wrong?

MapUser MapUser · Accepted Answer · 2018-09-10T10:30:48

Solved, the thing is the rendering starts at the top left corner, therefore 20037508.342789244 - 2445.984905126 × 6007 ~ 5342500, all right!

OL5 VectorTileLayer: Y coordinate of tile

1 Answers