https://github.com/gagan-bansal/web-mercator-tiles

Calculate map tiles for given map extent and zoom level. Considering map extent coordinates are in sperical (web) mercator projection.
https://github.com/gagan-bansal/web-mercator-tiles

tiles web-mercator

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Calculate map tiles for given map extent and zoom level. Considering map extent coordinates are in sperical (web) mercator projection.

• Host: GitHub
• URL: https://github.com/gagan-bansal/web-mercator-tiles
• Owner: gagan-bansal
• License: mit
• Created: 2015-01-21T17:38:35.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2022-04-04T06:35:05.000Z (over 2 years ago)
• Last Synced: 2024-11-06T14:52:39.497Z (11 days ago)
• Topics: tiles, web-mercator
• Language: JavaScript
• Size: 143 KB
• Stars: 11
• Watchers: 2
• Forks: 5
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# web-mercator-tiles

Calculate map tiles for given map extent and zoom level. Considering map extent coordinates are in sperical (web) mercator projection.

## installation

```

npm install web-mercator-tiles

```

## usage

```

var webMercatorTiles = require('web-mercator-tiles');

function: webMercatorTiles(extent,zoom)

parameters:

  extent: map extent of window or div in spherical mercator projeection (meters)

    {

      left: coordinate in meter,

      right: coordinate in meter,

      bottom: coordinate in meter,

      top: coordinate in meter

    }

  zoom: zoom level as integer

output: array of tiles object, where tile object is 

  {

    X: tile number in x direction

    Y: tile number in y direction 

    Z: tile number for zoom

    top: top of tile image position in window as pixel

    left: left of tile image position in window as pixel

  }

```

**TileExtent**, a static funtion to get tile extent in web mercator coordinates

param: {z: zoom leve, x: x tile no, y: y tile no}

### example

```javascript

var webMercatorTiles = require('web-mercator-tiles'),

  mapExtent = {

    left:-7929831.7499857,

    bottom:5227055.1160079,

    right:-7910263.8707475,

    top:5236839.0556271

  },

  zoom = 12;

tiles = webMercatorTiles(mapExtent,zoom);

// tiles are

/*

[ { X: 1237, Y: 1512, Z: 12, top: -192, left: -129 },

  { X: 1237, Y: 1513, Z: 12, top: 64, left: -129 },

  { X: 1238, Y: 1512, Z: 12, top: -192, left: 127 },

  { X: 1238, Y: 1513, Z: 12, top: 64, left: 127 },

  { X: 1239, Y: 1512, Z: 12, top: -192, left: 383 },

  { X: 1239, Y: 1513, Z: 12, top: 64, left: 383 } ]

*/

// Tile Extent

var tile = {z:12, x: 2953, y: 1697}

var extent = webMercatorTiles.TileExtent(tile)

// extent is

/*

{

  left: 8844681.416934315,

  right: 8854465.356554817,

  bottom: 3434162.806796398,

  top: 3443946.746416901,

  res: 38.21851414258813

}

*/

```

## Similar

Check [map-the-tiles](https://www.npmjs.com/package/map-the-tiles) for projections other than spherical mercator, and having spherical mecator as default projection.

## developing

Once you run

 

```npm isntall```

then for running test 

```npm run test```

to create build

```npm run build```

## license

This project is licensed under the terms of the MIT license.