added tms support (#19)

README.md

@@ -24,10 +24,19 @@ import {TerrainRGB} from '@watergis/terrain-rgb';
 
 const url = 'https://wasac.github.io/rw-terrain/tiles/{z}/{x}/{y}.png';
 const trgb = new TerrainRGB(url, 512);
+
 const elevation = await trgb.getElevation([30.0529622, -1.9575129], 15);
 console.log(elevation);
 ```
 
+TMS(Tile Map Service) tiles are also supported with
+
+```ts
+const trgb = new TerrainRGB(url, 512, 5, 15, true);
+```
+
+
 If it can't find tile, it will return 404 error.
 
 If its terrain RGB tilesets was resampled by gdal2tiles, the result of elevation might not be the same with original DEM image.
+

src/tile/base.ts

@@ -1,6 +1,7 @@
 import axios from 'axios';
 import { WebpMachine, loadBinaryData } from 'webp-hero';
-import { lngLatToGoogle } from 'global-mercator';
+import { lngLatToGoogle, lngLatToTile } from 'global-mercator';
+
 import PNG from '../png';
 
 /**
@@ -11,6 +12,8 @@ abstract class BaseTile {
 
   protected tileSize: number;
 
+  protected tms: boolean;
+
   protected minzoom: number;
 
   protected maxzoom: number;
@@ -19,14 +22,18 @@ abstract class BaseTile {
    * Constructor
    * @param url URL for terrain RGB raster tilesets
    * @param tileSize size of tile. 256 or 512
+   * @param tms whether it is Tile Map Service
    * @param minzoom minzoom for terrain RGB raster tilesets
    * @param maxzoom maxzoom for terrain RGB raster tilesets
+   * @param tms whether it is Tile Map Service
    */
-  constructor(url: string, tileSize: number, minzoom: number, maxzoom: number) {
+  constructor(url: string, tileSize: number, minzoom: number, maxzoom: number, tms: boolean) {
     this.url = url;
     this.tileSize = tileSize;
+    this.tms = tms;
     this.minzoom = minzoom;
     this.maxzoom = maxzoom;
+    this.tms = tms;
   }
 
   /**
@@ -46,7 +53,7 @@ abstract class BaseTile {
       } else if (z < this.minzoom) {
         zoom = this.minzoom;
       }
-      const tile = lngLatToGoogle([lng, lat], zoom);
+      const tile = this.tms ? lngLatToTile([lng, lat], zoom) : lngLatToGoogle([lng, lat], zoom);
       const url: string = this.url
         .replace(/{x}/g, tile[0].toString())
         .replace(/{y}/g, tile[1].toString())

src/tile/terrainrgb.ts

@@ -8,11 +8,12 @@ class TerrainRGB extends BaseTile {
    * Constructor
    * @param url URL for terrain RGB raster tilesets
    * @param tileSize size of tile. 256 or 512
+   * @param tms whether it is Tile Map Service
    * @param minzoom minzoom for terrain RGB raster tilesets. default is 5
    * @param maxzoom maxzoom for terrain RGB raster tilesets. default is 15
    */
-  constructor(url: string, tileSize: number, minzoom = 5, maxzoom = 15) {
-    super(url, tileSize, minzoom, maxzoom);
+  constructor(url: string, tileSize: number, minzoom = 5, maxzoom = 15, tms = false) {
+    super(url, tileSize, minzoom, maxzoom, tms);
   }
 
   /**