GeoGPXer is a JavaScript library designed to convert GPX data into GeoJSON format efficiently. It supports the conversion of waypoints, tracks, and routes, with additional handling for GPX extensions.
此腳本不應該直接安裝，它是一個供其他腳本使用的函式庫。欲使用本函式庫，請在腳本 metadata 寫上： // @require https://update.cn-greasyfork.org/scripts/523870/1614123/GeoGPXer.js
// ==UserScript==
// @name GeoGPXer
// @namespace https://github.com/JS55CT
// @description GeoGPXer is a JavaScript library designed to convert GPX data into GeoJSON format efficiently. It supports the conversion of waypoints, tracks, and routes, with additional handling for GPX extensions.
// @version 2.1.1
// @author JS55CT
// @license GNU General Public License v3.0
// @match *://this-library-is-not-supposed-to-run.com/*
// ==/UserScript==
/***********************************************************
* ## Project Home < https://github.com/JS55CT/WME-GeoFile/tree/main/GeoGPXer >
* Derived from logic of https://github.com/M-Reimer/gpx2geojson/tree/master (LGPL-3.0 license)
**************************************************************/
/**
* @desc The GeoGPXer namespace.
* @namespace
* @global
*/
var GeoGPXer = (function () {
// Define the GeoGPXer constructor
function GeoGPXer(obj) {
if (obj instanceof GeoGPXer) return obj;
if (!(this instanceof GeoGPXer)) return new GeoGPXer(obj);
this._wrapped = obj;
}
/**
* @desc Compares two coordinate arrays to determine if they are identical.
* Assumes coordinates are arrays of numbers representing geographic points.
* @param {Array} coord1 - First coordinate array.
* @param {Array} coord2 - Second coordinate array.
* @return {Boolean} Returns true if both coordinates are identical, false otherwise.
*/
function areCoordsSame(coord1, coord2) {
if (coord1.length !== coord2.length) return false;
for (let i = 0; i < coord1.length; i++) {
if (coord1[i] !== coord2[i]) return false;
}
return true;
}
/**
* @desc Parses GPX text and returns an XML Document.
* @param {String} gpxText - The GPX data as a string.
* @return {Document} Parsed XML Document.
*/
GeoGPXer.prototype.read = function (gpxText) {
const parser = new DOMParser();
const xmlDoc = parser.parseFromString(gpxText, 'application/xml');
// Check for parsing errors by looking for parser error tags
const parseErrors = xmlDoc.getElementsByTagName('parsererror');
if (parseErrors.length > 0) {
// If there are parsing errors, log them and throw an error
const errorMessages = Array.from(parseErrors)
.map((errorElement, index) => {
return `Parsing Error ${index + 1}: ${errorElement.textContent}`;
})
.join('\n');
console.error(errorMessages);
throw new Error('Failed to parse GPX. See console for details.');
}
// If parsing is successful, return the parsed XML document
return xmlDoc;
};
/**
* @desc Converts an XML Document to GeoJSON FeatureCollection.
* @param {Document} document - Parsed XML document of GPX data.
* @param {Boolean} includeElevation - Whether to include elevation data in coordinates.
* @return {Object} GeoJSON FeatureCollection.
*/
GeoGPXer.prototype.toGeoJSON = function (document, includeElevation = false) {
const features = [];
for (const n of document.firstChild.childNodes) {
switch (n.tagName) {
case 'wpt':
features.push(this.wptToPoint(n, includeElevation));
break;
case 'trk':
features.push(...this.trkToMultiLineStringOrPolygon(n, includeElevation));
break;
case 'rte':
const routeFeature = this.rteToLineStringOrPolygon(n, includeElevation);
if (routeFeature) {
features.push(routeFeature);
}
break;
}
}
return {
type: 'FeatureCollection',
features: features,
};
};
/**
* @desc Extracts coordinates from a node.
* @param {Node} node - GPX node containing coordinates.
* @param {Boolean} includeElevation - Whether to include elevation data.
* @return {Array} Array of coordinates [longitude, latitude, elevation].
*/
GeoGPXer.prototype.coordFromNode = function (node, includeElevation = false) {
const coords = [parseFloat(node.getAttribute('lon')), parseFloat(node.getAttribute('lat'))];
if (includeElevation) {
const eleNode = node.getElementsByTagName('ele')[0];
const elevation = eleNode ? parseFloat(eleNode.textContent) : 0;
coords.push(elevation);
}
return coords;
};
/**
* @desc Creates a GeoJSON feature.
* @param {String} type - Type of geometry (Point, LineString, etc.).
* @param {Array} coords - Coordinates for the geometry.
* @param {Object} props - Properties of the feature.
* @return {Object} GeoJSON feature.
*/
GeoGPXer.prototype.makeFeature = function (type, coords, props) {
return {
type: 'Feature',
geometry: {
type: type,
coordinates: coords,
},
properties: props,
};
};
/**
* @desc Converts a waypoint node to a GeoJSON Point feature.
* @param {Node} node - GPX waypoint node.
* @param {Boolean} includeElevation - Whether to include elevation data.
* @return {Object} GeoJSON Point feature.
*/
GeoGPXer.prototype.wptToPoint = function (node, includeElevation = false) {
const coord = this.coordFromNode(node, includeElevation);
const props = this.extractProperties(node);
return this.makeFeature('Point', coord, props);
};
/**
* @desc Converts a track node to a GeoJSON Polygon or MultiLineString features.
* Determines if each track segment should be converted to a Polygon by
* checking if it has four or more coordinate pairs with the first and last
* coordinates being the same. If not, it remains a MultiLineString.
* @param {Node} node - GPX track node.
* @param {Boolean} includeElevation - Whether to include elevation data in coordinates.
* @return {Array} Array of GeoJSON features which could either be Polygons or MultiLineStrings.
*/
GeoGPXer.prototype.trkToMultiLineStringOrPolygon = function (node, includeElevation = false) {
const features = [];
const props = this.extractProperties(node);
for (const n of node.childNodes) {
if (n.tagName === 'trkseg') {
const coords = [];
for (const trkpt of n.getElementsByTagName('trkpt')) {
coords.push(this.coordFromNode(trkpt, includeElevation));
}
if (coords.length >= 4 && areCoordsSame(coords[0], coords[coords.length - 1])) {
// Convert to Polygon if conditions are met
features.push(this.makeFeature('Polygon', [coords], props));
} else {
// Otherwise treat as MultiLineString
features.push(this.makeFeature('MultiLineString', [coords], props));
}
}
}
return features;
};
/**
* @desc Converts a route node to a GeoJSON feature as either a Polygon or LineString.
* Determines whether the route can be converted into a Polygon by checking
* if it has four or more coordinate pairs with the first and last coordinates
* being the same. If not, it treats the route as a LineString.
* @param {Node} node - GPX route node.
* @param {Boolean} includeElevation - Whether to include elevation data in coordinates.
* @return {Object} GeoJSON feature, which could be a Polygon or LineString.
*/
GeoGPXer.prototype.rteToLineStringOrPolygon = function (node, includeElevation = false) {
const coords = [];
const props = this.extractProperties(node);
for (const n of node.childNodes) {
if (n.tagName === 'rtept') {
coords.push(this.coordFromNode(n, includeElevation));
}
}
if (coords.length >= 4 && areCoordsSame(coords[0], coords[coords.length - 1])) {
// Convert to Polygon if conditions are met
return this.makeFeature('Polygon', [coords], props);
} else {
// Otherwise treat as LineString
return this.makeFeature('LineString', coords, props);
}
};
/**
* @desc Extracts properties from a GPX node.
* @param {Node} node - GPX node.
* @return {Object} Properties extracted from the node.
*/
GeoGPXer.prototype.extractProperties = function (node) {
const props = {};
for (const n of node.childNodes) {
if (n.nodeType === Node.ELEMENT_NODE && n.tagName !== 'extensions') {
props[n.tagName] = n.textContent;
}
}
const extensions = node.getElementsByTagName('extensions');
if (extensions.length > 0) {
for (const ext of extensions[0].childNodes) {
if (ext.nodeType === Node.ELEMENT_NODE) {
props[`ex_${ext.tagName}`] = ext.textContent;
}
}
}
return props;
};
return GeoGPXer; // Return the GeoGPXer constructor
})();