heli-agri/lib/source/OGCVectorTile.js

HeliAgri is a high-performance, feature-packed library for creating interactive maps on the web. It can display map tiles, vector data and markers loaded from any source on any web page. OpenLayers has been developed to further the use of geographic infor

/**
 * @module ol/source/OGCVectorTile
 */

import VectorTile from './VectorTile.js';
import {getTileSetInfo} from './ogcTileUtil.js';
import {error as logError} from '../console.js';

/**
 * @typedef {Object} Options
 * @property {string} url URL to the OGC Vector Tileset endpoint.
 * @property {Object} [context] A lookup of values to use in the tile URL template.  The `{tileMatrix}`
 * (zoom level), `{tileRow}`, and `{tileCol}` variables in the URL will always be provided by the source.
 * @property {import("../format/Feature.js").default} format Feature parser for tiles.
 * @property {string} [mediaType] The content type for the tiles (e.g. "application/vnd.mapbox-vector-tile").  If not provided,
 * the source will try to find a link with rel="item" that uses a vector type supported by the configured format.
 * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
 * @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
 * @property {number} [cacheSize] Initial tile cache size. Will auto-grow to hold at least twice the number of tiles in the viewport.
 * @property {boolean} [overlaps=true] This source may have overlapping geometries. Setting this
 * to `false` (e.g. for sources with polygons that represent administrative
 * boundaries or TopoJSON sources) allows the renderer to optimise fill and
 * stroke operations.
 * @property {import("../proj.js").ProjectionLike} [projection='EPSG:3857'] Projection of the tile grid.
 * @property {typeof import("../VectorTile.js").default} [tileClass] Class used to instantiate image tiles.
 * Default is {@link module:ol/VectorTile~VectorTile}.
 * @property {number} [transition] A duration for tile opacity
 * transitions in milliseconds. A duration of 0 disables the opacity transition.
 * @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
 * When set to `false`, only one world
 * will be rendered. When set to `true`, tiles will be wrapped horizontally to
 * render multiple worlds.
 * @property {number|import("../array.js").NearestDirectionFunction} [zDirection=1]
 * Choose whether to use tiles with a higher or lower zoom level when between integer
 * zoom levels. See {@link module:ol/tilegrid/TileGrid~TileGrid#getZForResolution}.
 */

/**
 * @classdesc
 * Layer source for map tiles from an [OGC API - Tiles](https://ogcapi.ogc.org/tiles/) service that provides "vector" type tiles.
 * The service must conform to at least the core (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/core)
 * and tileset (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/tileset) conformance classes.
 *
 * Vector tile sets may come in a variety of formats (e.g. GeoJSON, MVT).  The `format` option is used to determine
 * which of the advertised media types is used.  If you need to force the use of a particular media type, you can
 * provide the `mediaType` option.
 * @api
 */
class OGCVectorTile extends VectorTile {
  /**
   * @param {Options} options OGC vector tile options.
   */
  constructor(options) {
    super({
      attributions: options.attributions,
      attributionsCollapsible: options.attributionsCollapsible,
      cacheSize: options.cacheSize,
      format: options.format,
      overlaps: options.overlaps,
      projection: options.projection,
      tileClass: options.tileClass,
      transition: options.transition,
      wrapX: options.wrapX,
      zDirection: options.zDirection,
      state: 'loading',
    });

    const sourceInfo = {
      url: options.url,
      projection: this.getProjection(),
      mediaType: options.mediaType,
      supportedMediaTypes: options.format.supportedMediaTypes,
      context: options.context || null,
    };

    getTileSetInfo(sourceInfo)
      .then(this.handleTileSetInfo_.bind(this))
      .catch(this.handleError_.bind(this));
  }

  /**
   * @param {import("./ogcTileUtil.js").TileSetInfo} tileSetInfo Tile set info.
   * @private
   */
  handleTileSetInfo_(tileSetInfo) {
    this.tileGrid = tileSetInfo.grid;
    this.setTileUrlFunction(tileSetInfo.urlFunction, tileSetInfo.urlTemplate);
    this.setState('ready');
  }

  /**
   * @private
   * @param {Error} error The error.
   */
  handleError_(error) {
    logError(error);
    this.setState('error');
  }
}

export default OGCVectorTile;