Angular ワールド ユーティリティ

リソース トピックは、Angular 地理データの生成に役立つユーティリティの実装です。

コード スニペット

export default class WorldUtils {

    // calculate geo-paths between two locations using great circle formula
    public static calcPaths(origin: any, dest: any): any[] {
        let interval = 200;
        let paths: any[] = [[]];
        let pathID = 0;
        let distance = this.calcDistance(origin, dest);
        if (distance <= interval) {
            paths[pathID].push({ x: origin.lon, y: origin.lat });
            paths[pathID].push({ x: dest.lon, y: dest.lat });
        } else {
            let current = origin;
            let previous = origin;

            for (let dist = interval; dist <= distance; dist += interval)
            {
                previous = current
                paths[pathID].push({ x: current.lon, y: current.lat });

                let bearing = this.calcBearing(current, dest);
                current = this.calcDestination(current, bearing, interval);
                // ensure geo-path wrap around the world through the new date-line
                if (previous.lon > 150 && current.lon < -150) {
                    paths[pathID].push({ x: 180, y: current.lat });
                    paths.push([]);
                    pathID++
                    current = { lon: -180, lat: current.lat }
                } else if (previous.lon < -150 && current.lon > 150) {
                    paths[pathID].push({ x: -180, y: current.lat });
                    paths.push([]);
                    pathID++
                    current = { lon: 180, lat: current.lat }
                }
            }
            paths[pathID].push({ x: dest.lon, y: dest.lat });
        }
        return paths;
    }

    // calculate bearing angle between two locations
    public static calcBearing(origin: any, dest: any) : number
    {
        origin = this.toRadianLocation(origin);
        dest = this.toRadianLocation(dest);
        let range = (dest.lon - origin.lon);
        let y = Math.sin(range) * Math.cos(dest.lat);
        let x = Math.cos(origin.lat) * Math.sin(dest.lat) -
                Math.sin(origin.lat) * Math.cos(dest.lat) * Math.cos(range);
        let angle = Math.atan2(y, x);
        return this.toDegreesNormalized(angle);
    }

    // calculate destination for origin location and travel distance
    public static calcDestination(origin: any, bearing: number, distance: number): any {
        let radius = 6371.0;
        origin = this.toRadianLocation(origin);
        bearing = this.toRadians(bearing);
        distance = distance / radius; // angular distance in radians

        let lat = Math.asin(Math.sin(origin.lat) * Math.cos(distance) +
                       Math.cos(origin.lat) * Math.sin(distance) * Math.cos(bearing));
        let x = Math.sin(bearing) * Math.sin(distance) * Math.cos(origin.lat);
        let y = Math.cos(distance) - Math.sin(origin.lat) * Math.sin(origin.lat);
        let lon = origin.lon + Math.atan2(x, y);
        // normalize lon to coordinate between -180º and +180º
        lon = (lon + 3 * Math.PI) % (2 * Math.PI) - Math.PI;

        lon = this.toDegrees(lon);
        lat = this.toDegrees(lat);

        return { lon: lon, lat: lat };
    }

    // calculate distance between two locations
    public static calcDistance(origin: any, dest: any) : number {
        origin = this.toRadianLocation(origin);
        dest = this.toRadianLocation(dest);
        let sinProd = Math.sin(origin.lat) * Math.sin(dest.lat);
        let cosProd = Math.cos(origin.lat) * Math.cos(dest.lat);
        let lonDelta = (dest.lon - origin.lon);

        let angle = Math.acos(sinProd + cosProd * Math.cos(lonDelta));
        let distance = angle * 6371.0;
        return distance; // * 6371.0; // in km
    }

    public static toRadianLocation(geoPoint: any) : any {
        let x = this.toRadians(geoPoint.lon);
        let y = this.toRadians(geoPoint.lat);
        return { lon: x, lat: y };
    }

    public static toRadians(degrees: number) : number
    {
        return degrees * Math.PI / 180;
    }

    public static toDegrees(radians: number) : number {
        return (radians * 180.0 / Math.PI);
    }

    public static toDegreesNormalized(radians: number) : number
    {
        let degrees = this.toDegrees(radians);
        degrees = (degrees + 360) % 360;
        return degrees;
    }

    // converts latitude coordinate to a string
    public static toStringLat(latitude: number) : string {
        let str = Math.abs(latitude).toFixed(1) + "°";
        return latitude > 0 ? str + "N" : str + "S";
    }

    // converts longitude coordinate to a string
    public static toStringLon(coordinate: number) : string {
        let val = Math.abs(coordinate);
        let str = val < 100 ? val.toFixed(1) : val.toFixed(0);
        return coordinate > 0 ? str + "°E" : str + "°W";
    }

    public static toStringAbbr(value: number) : string {
        if (value > 1000000000000) {
            return (value / 1000000000000).toFixed(1) + " T"
        } else if (value > 1000000000) {
            return (value / 1000000000).toFixed(1) + " B"
        } else if (value > 1000000) {
            return (value / 1000000).toFixed(1) + " M"
        } else if (value > 1000) {
            return (value / 1000).toFixed(1) + " K"
        }
        return value.toFixed(0);
    }

    public static getLongitude(location: any) : number {
        if (location.x) return location.x;
        if (location.lon) return location.lon;
        if (location.longitude) return location.longitude;
        return Number.NaN;
    }

    public static getLatitude(location: any) : number {
        if (location.y) return location.y;
        if (location.lat) return location.lat;
        if (location.latitude) return location.latitude;
        return Number.NaN;
    }

    public static getBounds(locations: any[]) : any {
        let minLat = 90;
        let maxLat = -90;
        let minLon = 180;
        let maxLon = -180;

        for (const location of locations) {
            const crrLon = this.getLongitude(location);
            if (!Number.isNaN(crrLon)) {
                minLon = Math.min(minLon, crrLon);
                maxLon = Math.max(maxLon, crrLon);
            }

            const crrLat = this.getLatitude(location);
            if (!Number.isNaN(crrLat)) {
                minLat = Math.min(minLat, crrLat);
                maxLat = Math.max(maxLat, crrLat);
            }
        }

        const geoBounds = {
            left: minLon,
            top: minLat,
            width: Math.abs(maxLon - minLon),
            height: Math.abs(maxLat - minLat)
        };
        return geoBounds;
    }
}

API リファレンス