127 行
无行尾
4.2 KiB
JavaScript
127 行
无行尾
4.2 KiB
JavaScript
const isValidLocatorString = locatorString => locatorString.match(/^[A-Ra-r][A-Ra-r]\d\d[A-Xa-x][A-Xa-x]/) !== null;
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const charToNumber = char => char.toUpperCase().charCodeAt(0) - CHAR_CODE_OFFSET;
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const numberToChar = number => String.fromCharCode(number + CHAR_CODE_OFFSET);
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const CHAR_CODE_OFFSET = 65;
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const degToRad = deg => (deg % 360) * Math.PI / 180;
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const radToDeg = rad => (rad / Math.PI *180) % 360;
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const isValidPoint = (lat, lng) => (lat >= -90 && lat <= 90) && (lng >= -180 && lng <= 180);
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function ConvertDDToDMS(lat, lng) {
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var LatLng = [];
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if (lng < -180) {
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lng = lng + 360;
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}
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if (lng > 180) {
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lng = lng - 360;
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}
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LatLng['latDeg'] = (lat < 0 ? "S" : "N") + " " + pad((0 |(lat < 0 ? (lat = -lat) : lat)), 2) + "° " + pad(0 | (((lat += 1e-9) % 1) * 60),2) + "' " + ((0 | (((lat * 60) % 1) * 6000)) / 100) + "\"";
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LatLng['lngDeg'] = (lng < 0 ? "W" : "E") + " " + pad((0 | (lng < 0 ? (lng = -lng) : lng)), 3) + "° " + pad(0 | (((lng += 1e-9) % 1) * 60),2) + "' " + ((0 | (((lng * 60) % 1) * 6000)) / 100) + "\"";
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return LatLng;
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}
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function pad(n, width, z) {
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z = z || '0';
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n = n + '';
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return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
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}
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const latLngToLocator = (lat, lng) => {
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if (lng < -180) {
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lng = lng + 360;
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}
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if (lng > 180) {
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lng = lng - 360;
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}
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if (!isValidPoint(lat, lng)) {
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throw new Error('Input is not a valid coordinate');
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}
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const longitude = lng + 180;
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const latitude = lat + 90;
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const fieldLng = numberToChar(Math.floor(longitude / 20));
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const fieldLat = numberToChar(Math.floor(latitude / 10));
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const squareLng = Math.floor(longitude % 20 / 2);
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const squareLat = Math.floor(latitude % 10);
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const subsquareLng = numberToChar(Math.floor((longitude % 20 % 2) * 12)).toLowerCase();
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const subsquareLat = numberToChar((latitude % 10 - squareLat) * 24).toLowerCase();
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return fieldLng + fieldLat + squareLng + squareLat + subsquareLng + subsquareLat;
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};
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function onMapMove(event) {
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var LatLng = event.latlng;
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var lat = LatLng.lat;
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var lng = LatLng.lng;
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var LatLng2 = ConvertDDToDMS(lat, lng);
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$('#latDeg').html(LatLng2.latDeg);
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$('#lngDeg').html(LatLng2.lngDeg);
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var locator = latLngToLocator(lat,lng);
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$('#locator').html(locator);
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var distance = bearingDistance(homegrid, locator);
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$('#bearing').html(distance.deg + ' deg');
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$('#distance').html(Math.round(distance.km * 10) / 10 + ' km');
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};
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const bearingDistance = (from, to) => {
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const fromCoords = locatorToLatLng(from);
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const toCoords = locatorToLatLng(to);
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const dLat = degToRad(toCoords[0] - fromCoords[0]);
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const dLon = degToRad(toCoords[1] - fromCoords[1]);
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const fromLat = degToRad(fromCoords[0]);
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const toLat = degToRad(toCoords[0]);
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const a = Math.pow(Math.sin(dLat / 2), 2) + Math.pow(Math.sin(dLon / 2), 2) * Math.cos(fromLat) * Math.cos(toLat);
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const b = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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const y = (dLon) * Math.cos(fromLat) * Math.cos(toLat);
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const x = Math.sin(toLat) - Math.sin(fromLat) * Math.cos(b);
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let az = Math.atan2(y, x);
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if (az < 0) {
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az += 2 * Math.PI;
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}
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return {
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km: b * 6371,
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deg: calcAngle(fromCoords, toCoords)
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};
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};
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var calcAngle = function (p1, p2) {
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var lat1 = p1[0] / 180 * Math.PI;
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var lat2 = p2[0] / 180 * Math.PI;
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var lng1 = p1[1] / 180 * Math.PI;
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var lng2 = p2[1] / 180 * Math.PI;
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var y = Math.sin(lng2-lng1) * Math.cos(lat2);
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var x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(lng2-lng1);
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var brng = (Math.atan2(y, x) * 180 / Math.PI + 360).toFixed(0);
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return (brng % 360);
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}
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const locatorToLatLng = (locatorString) => {
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locatorString += 'll'; // append subsquare in case is 4 chars long... If not, is ignored.
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if (!isValidLocatorString(locatorString)) {
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throw new Error('Input is not valid locator string');
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}
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const fieldLng = charToNumber(locatorString[0]) * 20;
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const fieldLat = charToNumber(locatorString[1]) * 10;
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const squareLng = Number.parseInt(locatorString[2]) * 2;
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const squareLat = Number.parseInt(locatorString[3]);
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const subsquareLng = (charToNumber(locatorString[4]) + 0.5) / 12;
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const subsquareLat = (charToNumber(locatorString[5]) + 0.5) / 24;
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return [
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fieldLat + squareLat + subsquareLat - 90,
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fieldLng + squareLng + subsquareLng - 180
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];
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}; |