thematic-earth/gcslib/parsers/geojson-parser.class.js

HTML-based, whole-Earth thematic maps using locally hosted data layers

/* Copyright (c) 2023 Read Write Tools. Legal use subject to the Thematic Earth Software License Agreement. */
import GcsPointFeature from'../gcs/gcs-point-feature.class.js';import GcsLineFeature from'../gcs/gcs-line-feature.class.js';import{GcsPolygonFeature}from'../gcs/gcs-polygon-feature.class.js';import{PolygonRing}from'../gcs/gcs-polygon-feature.class.js';import{PolygonCutouts}from'../gcs/gcs-polygon-feature.class.js';import Coords from'../util/coords.class.js';import expect from'../softlib/expect.js';import aver from'../softlib/aver.js';import terminal from'../softlib/terminal.js';export default class GeojsonParser{constructor(e){expect(e,'GcsHoldingArea'),this.gcsFeaturePoints=e.gcsFeaturePoints,this.gcsFeatureLines=e.gcsFeatureLines,this.gcsFeaturePolygons=e.gcsFeaturePolygons,Object.seal(this)}parseString(e){expect(e,'String');var t=JSON.parse(e);return this.parseObject(t)}parseObject(e){expect(e,'Object');try{return this.handleAmbiguousJson(e),!0}catch(e){return terminal.caught(e),!1}}handleAmbiguousJson(e,t){if('Array'==e.constructor.name)for(let t=0;t<e.length;t++)this.handleAmbiguousJson(e[t]);else if('Object'==e.constructor.name)switch(e.type){case'FeatureCollection':return void this.handleFeatureCollection(e);case'Feature':return void this.handleFeature(e,t);default:terminal.trace(`ignoring geoJSON object type ${geojsonObj.type}`)}else terminal.abnormal(`valid RFC 7946 geoJSON objects MUST have a type ${e}`)}handleFeatureCollection(e){aver('FeatureCollection'==e.type),expect(e.features,'Array');for(let r=0;r<e.features.length;r++){var t=r;this.handleAmbiguousJson(e.features[r],t)}}handleFeature(e,t){if(aver('Feature'==e.type),expect(e.geometry,['Object','null']),expect(e.properties,['Object','null','undefined']),null==e.geometry)return void terminal.trace(`feature ${t} has no geometry, skipping`);const r=e.geometry.coordinates;expect(r,'Array');const o=e.geometry.type;switch(expect(o,'String'),o){case'Point':this.handlePoint(e.properties,r);break;case'MultiPoint':for(let t=0;t<r.length;t++)this.handlePoint(e.properties,r[t]);break;case'LineString':this.handleLine(e.properties,r);break;case'MultiLineString':for(let t=0;t<r.length;t++)this.handleLine(e.properties,r[t]);break;case'Polygon':this.handlePolygon(e.properties,r);break;case'MultiPolygon':for(let t=0;t<r.length;t++)this.handlePolygon(e.properties,r[t]);break;case'GeometryCollection':terminal.trace('GeometryCollection not supported, try topojson');break;default:terminal.abnormal(`Expected an RFC 7946 geoJSON geometry, but got type ${e.type}`)}}handlePoint(e,t){expect(e,'Object'),expect(t,'Array');const r=this.copyProperties(e),o=new Coords(t[0],t[1]);this.createPoint(r,o)}createPoint(e,t){expect(e,'Object'),expect(t,'Coords');var r=new GcsPointFeature;r.kvPairs=e,r.discretePoint=t,this.gcsFeaturePoints.push(r)}handleLine(e,t){expect(e,'Object'),expect(t,'Array');const r=this.copyProperties(e),o=[];for(let e=0;e<t.length;e++){const r=t[e];o.push(new Coords(r[0],r[1]))}this.createLine(r,o)}createLine(e,t){expect(e,'Object'),expect(t,'Array');var r=new GcsLineFeature;r.kvPairs=e,r.lineSegment=t,this.gcsFeatureLines.push(r)}handlePolygon(e,t){expect(e,'Object'),expect(t,'Array');const r=this.copyProperties(e),o=new PolygonRing,s=new PolygonCutouts;for(let e=0;e<t.length;e++){const r=t[e],a=r.length;if(0==e){for(let e=0;e<a;e++)o.push(new Coords(r[e][0],r[e][1]));aver(o[0].longitude==o[a-1].longitude),aver(o[0].latitude==o[a-1].latitude)}else{var n=new PolygonRing;for(let e=0;e<a;e++)n.push(new Coords(r[e][0],r[e][1]));aver(n[0].longitude==n[a-1].longitude),aver(n[0].latitude==n[a-1].latitude),s.push(n)}}this.createPolygon(r,o,s)}createPolygon(e,t,r){expect(e,'Object'),expect(t,'PolygonRing'),expect(r,'PolygonCutouts');var o=new GcsPolygonFeature;o.kvPairs=e,o.outerRing=t,o.innerRings=r,this.gcsFeaturePolygons.push(o)}copyProperties(e){return expect(e,'Object'),null==e||null==e?{}:Object.assign({},e)}}