Develop Reference

Leaflet Routing Machine - update/redraw route

I'm new about Laflet Routing Machine (liedman) https://www.liedman.net/leaflet-routing-machine/ and I would like to update the first route calculated every 30 seconds because I would like refresh it and I don't need to make many server request.
I'll make a setInterval but at the moment I need to know if it works and if this is the way... this is my code:
routingControl = L.Routing.control({
waypoints: [
L.latLng(43.12, 11.99),
L.latLng(43.37, 12.08)
]
createMarker: function() { return null; },
routeWhileDragging: false,
draggableWaypoints: false,
reverseWaypoints: false,
fitSelectedRoutes: true,
addWaypoints: false
}).addTo(OSM_Map);
var newLat = routingControl.options.waypoints[0].lat+0.01;
var newLng = routingControl.options.waypoints[0].lng+0.01;
setTimeout(function () {
routingControl.options.waypoints=[
L.latLng(newLat, newLng),
routingControl.options.waypoints[1]
];
}, 10000);
With setTimeout I change the start point (adding 0.01) and checking the waypoints with console.dir they are changed but not the drawn route... how I can refresh it?

The options are only used when initializing the routing control. Changing them afterwards does nothing, since the control uses its own waypoints internally.
You should be able to use the setWaypoints function like this
setInterval(function () {
var newWaypoint = routingControl.getWaypoints()[0].latLng;
var newLat = newWaypoint.lat + 0.01;
var newLng = newWaypoint.lng + 0.01;
routingControl.setWaypoints([
L.latLng(newLat, newLng),
routingControl.options.waypoints[1]
]);
}, 10000);
Unlike the options, the getWaypoints always returns the current waypoints, so you can freely modify them.
setWaypoints will then trigger a change event for the routes and update them accordingly.
Here's a working fiddle you can play around with

Best way to get most precise location on mobile with js only

I'm creating a webapp/pwa where I need a precise user location, say under 30-40 meters, I have tried using Radar.io, as well as the geolocation api but still have not been able to get a precise enough location on my iphone on safari. I usually get 60-70 meter accuracy, how would I get more accurate than this? I want the accuracy to be that of the Nike Run Club app for reference.

I have used the Geolocation API many times and it's very precise if you configure it properly.
Here's a snippet I've used in a similar project:
// check if geolocation is supported on this browser
if (navigator.geolocation) {
const timeoutVal = 10 * 1000 * 1000; // set a timeout value for the query
navigator.geolocation.getCurrentPosition(
// what to do if query succeeds
((position) => alert("Latitude: " + position.coords.latitude + ", Longitude: " + position.coords.longitude)),
((error) => {
// what to do if query fails:
const errors = {
1: 'Permission denied',
2: 'Position unavailable',
3: 'Request timeout'
};
alert("Error: " + errors[error.code]); // print the error
}),
// these 3 parameters are very important, especially the first one
{ enableHighAccuracy: true, timeout: timeoutVal, maximumAge: 0 }
);
}
else {
alert("Geolocation is not supported by this browser");
}

How to delay a function like this? [duplicate]

Using the Google Geocoder v3, if I try to geocode 20 addresses, I get an OVER_QUERY_LIMIT unless I time them to be ~1 second apart, but then it takes 20 seconds before my markers are all placed.
Is there any other way to do it, other than storing the coordinates in advance?

No, there is not really any other way : if you have many locations and want to display them on a map, the best solution is to :
fetch the latitude+longitude, using the geocoder, when a location is created
store those in your database, alongside the address
and use those stored latitude+longitude when you want to display the map.
This is, of course, considering that you have a lot less creation/modification of locations than you have consultations of locations.
Yes, it means you'll have to do a bit more work when saving the locations -- but it also means :
You'll be able to search by geographical coordinates
i.e. "I want a list of points that are near where I'm now"
Displaying the map will be a lot faster
Even with more than 20 locations on it
Oh, and, also (last but not least) : this will work ;-)
You will less likely hit the limit of X geocoder calls in N seconds.
And you will less likely hit the limit of Y geocoder calls per day.

You actually do not have to wait a full second for each request. I found that if I wait 200 miliseconds between each request I am able to avoid the OVER_QUERY_LIMIT response and the user experience is passable. With this solution you can load 20 items in 4 seconds.
$(items).each(function(i, item){
setTimeout(function(){
geoLocate("my address", function(myLatlng){
...
});
}, 200 * i);
}

Unfortunately this is a restriction of the Google maps service.
I am currently working on an application using the geocoding feature, and I'm saving each unique address on a per-user basis. I generate the address information (city, street, state, etc) based on the information returned by Google maps, and then save the lat/long information in the database as well. This prevents you from having to re-code things, and gives you nicely formatted addresses.
Another reason you want to do this is because there is a daily limit on the number of addresses that can be geocoded from a particular IP address. You don't want your application to fail for a person for that reason.

I'm facing the same problem trying to geocode 140 addresses.
My workaround was adding usleep(100000) for each loop of next geocoding request. If status of the request is OVER_QUERY_LIMIT, the usleep is increased by 50000 and request is repeated, and so on.
And of cause all received data (lat/long) are stored in XML file not to run request every time the page is loading.

EDIT:
Forgot to say that this solution is in pure js, the only thing you need is a browser that supports promises https://developer.mozilla.org/it/docs/Web/JavaScript/Reference/Global_Objects/Promise
For those who still needs to accomplish such, I've written my own solution that combines promises with timeouts.
Code:
/*
class: Geolocalizer
- Handles location triangulation and calculations.
-- Returns various prototypes to fetch position from strings or coords or dragons or whatever.
*/
var Geolocalizer = function () {
this.queue = []; // queue handler..
this.resolved = [];
this.geolocalizer = new google.maps.Geocoder();
};
Geolocalizer.prototype = {
/*
#fn: Localize
#scope: resolve single or multiple queued requests.
#params: <array> needles
#returns: <deferred> object
*/
Localize: function ( needles ) {
var that = this;
// Enqueue the needles.
for ( var i = 0; i < needles.length; i++ ) {
this.queue.push(needles[i]);
}
// return a promise and resolve it after every element have been fetched (either with success or failure), then reset the queue.
return new Promise (
function (resolve, reject) {
that.resolveQueueElements().then(function(resolved){
resolve(resolved);
that.queue = [];
that.resolved = [];
});
}
);
},
/*
#fn: resolveQueueElements
#scope: resolve queue elements.
#returns: <deferred> object (promise)
*/
resolveQueueElements: function (callback) {
var that = this;
return new Promise(
function(resolve, reject) {
// Loop the queue and resolve each element.
// Prevent QUERY_LIMIT by delaying actions by one second.
(function loopWithDelay(such, queue, i){
console.log("Attempting the resolution of " +queue[i-1]);
setTimeout(function(){
such.find(queue[i-1], function(res){
such.resolved.push(res);
});
if (--i) {
loopWithDelay(such,queue,i);
}
}, 1000);
})(that, that.queue, that.queue.length);
// Check every second if the queue has been cleared.
var it = setInterval(function(){
if (that.queue.length == that.resolved.length) {
resolve(that.resolved);
clearInterval(it);
}
}, 1000);
}
);
},
/*
#fn: find
#scope: resolve an address from string
#params: <string> s, <fn> Callback
*/
find: function (s, callback) {
this.geolocalizer.geocode({
"address": s
}, function(res, status){
if (status == google.maps.GeocoderStatus.OK) {
var r = {
originalString: s,
lat: res[0].geometry.location.lat(),
lng: res[0].geometry.location.lng()
};
callback(r);
}
else {
callback(undefined);
console.log(status);
console.log("could not locate " + s);
}
});
}
};
Please note that it's just a part of a bigger library I wrote to handle google maps stuff, hence comments may be confusing.
Usage is quite simple, the approach, however, is slightly different: instead of looping and resolving one address at a time, you will need to pass an array of addresses to the class and it will handle the search by itself, returning a promise which, when resolved, returns an array containing all the resolved (and unresolved) address.
Example:
var myAmazingGeo = new Geolocalizer();
var locations = ["Italy","California","Dragons are thugs...","China","Georgia"];
myAmazingGeo.Localize(locations).then(function(res){
console.log(res);
});
Console output:
Attempting the resolution of Georgia
Attempting the resolution of China
Attempting the resolution of Dragons are thugs...
Attempting the resolution of California
ZERO_RESULTS
could not locate Dragons are thugs...
Attempting the resolution of Italy
Object returned:
The whole magic happens here:
(function loopWithDelay(such, queue, i){
console.log("Attempting the resolution of " +queue[i-1]);
setTimeout(function(){
such.find(queue[i-1], function(res){
such.resolved.push(res);
});
if (--i) {
loopWithDelay(such,queue,i);
}
}, 750);
})(that, that.queue, that.queue.length);
Basically, it loops every item with a delay of 750 milliseconds between each of them, hence every 750 milliseconds an address is controlled.
I've made some further testings and I've found out that even at 700 milliseconds I was sometimes getting the QUERY_LIMIT error, while with 750 I haven't had any issue at all.
In any case, feel free to edit the 750 above if you feel you are safe by handling a lower delay.
Hope this helps someone in the near future ;)

I have just tested Google Geocoder and got the same problem as you have.
I noticed I only get the OVER_QUERY_LIMIT status once every 12 requests
So I wait for 1 second (that's the minimum delay to wait)
It slows down the application but less than waiting 1 second every request
info = getInfos(getLatLng(code)); //In here I call Google API
record(code, info);
generated++;
if(generated%interval == 0) {
holdOn(delay); // Every x requests, I sleep for 1 second
}
With the basic holdOn method :
private void holdOn(long delay) {
try {
Thread.sleep(delay);
} catch (InterruptedException ex) {
// ignore
}
}
Hope it helps

This worked well for me, after intermittent trial and error over the past couple days. I am using react instant-search-hooks via Algolia with Nextjs and Sanity for a new jobs site for a large company.
Postal Code is a facet for filtering/sorting/query matching that is defined in the algolia index. In another script file, I map out all of these facets (postal code, city, etc); Now that I have 100 returned files they can be mapped out by iterating through a mapped asynchronous import and the lat/lng coords matched to the corresponding zip codes defining a job posting (there are ~2500 postings but only ~100 zip codes to narrow down the coordinates of)
import * as dotenv from "dotenv";
dotenv.config();
import {
googleNetwork,
axiosConfig as googleAxiosConfig
} from "../utils/google-axios";
import JSONData from "../../public/data/postalCode/2022/05/26.json";
import fs from "fs";
import { join } from "path";
import type { GeneratedGeolocData } from "../types/algolia";
import { timezoneHelper } from "../utils/timezone-helper";
import { Unenumerate } from "../types/helpers";
let i = 0;
i < JSONData.postalCodes.facetHits.length;
i++;
const getGeoCode = (
record: Unenumerate<typeof JSONData.postalCodes.facetHits>
) =>
function () {
return JSONData.postalCodes.facetHits.map(async (data = record, u) => {
const googleBase = process.env.NEXT_PUBLIC_GOOGLE_MAPS_BASE_PATH ?? "";
const googleApiKey =
process.env.NEXT_PUBLIC_TAKEDA_JOBS_GOOGLE_SERVICES ?? "";
const params: (string | undefined)[][] = [
["address", data.value],
["key", googleApiKey]
];
const query = params
.reduce<string[]>((arr, [k, v]) => {
if (v) arr.push(`${k}=${encodeURIComponent(v)}`);
return arr;
}, [])
.join("&");
return await googleNetwork("GET")
.get(`${googleBase}geocode/json?${query}`, googleAxiosConfig)
.then(dat => {
const geoloc = dat.data as GeneratedGeolocData;
const {
[0]: Year,
[2]: Month,
[4]: Day
} = new Date(Date.now())
.toISOString()
.split(/(T)/)[0]
.split(/([-])/g);
const localizedTimestamp = timezoneHelper({
dateField: new Date(Date.now()),
timezone: "America/Chicago"
});
return setTimeout(
() =>
fs.appendFileSync(
join(
process.cwd(),
`public/data/geoloc/${Year}/${Month}/${Day}-${[i]}.json`
),
JSON.stringify(
{
generated: localizedTimestamp,
_geoloc: {
postalCode: data.value,
geolocation: geoloc
}
},
null,
2
)
),
1000
);
});
});
};
getGeoCode(JSONData.postalCodes.facetHits[i]);
It took a lot less time than anticipated -- under 4 seconds for 100 unique results to generate
Context on the Unenumerate type -- Unenumerate strips the internal repeating unit within an array:
type Unenumerate<T> = T extends Array<infer U> ? U : T;

Try Catch for error message in google maps api

I an using javascript and am getting an message that I have exceeded my daily request quota for this API. Is there a way to capture this error message in a try catch block so when I go over my quota I can execute another piece of code. I have seen several similar posts, but nothing that has been helpful. Here is my code.
(function (window, google, lat, lng) {
var options = {
center: {
lat: Number(lat),
lng: Number(lng)
},
zoom: 5,
disableDefaultUI: true,
scrollwheel: true,
draggable: false
},
element = document.getElementById('map-canvas')
var map = new google.maps.Map(element, options)
}(window, window.google, result[i]['latitude'], result[i]['longitude']));

Update
As per the documentation:
if you want to programmatically detect an authentication failure (for example to automatically send an beacon) you can prepare a callback function. If the following global function is defined it will be called when the authentication fails. function gm_authFailure() {//code}
Here is a list of errors that the gm_authFaliure function should be able to catch. It also mentions a OverQuotaMapError error.
As per the documentation:
if too many requests are made within a certain time period, the API returns an OVER_QUERY_LIMIT response code.
So you should check the response code. If the Google maps javascript library does not allow to access to the response code then I recommend making a HTTP request to the API to get the response code.
function initMap(window, google, lat, lng) {
var options = {
center: {
lat: Number(lat),
lng: Number(lng)
},
zoom: 5,
disableDefaultUI: true,
scrollwheel: true,
draggable: false
},
element = document.getElementById('map-canvas'),
map = new google.maps.Map(element, options);
};
function googleMapsCustomError(){
alert('Google Maps custom error triggered');
}
// if you want to respond to a specific error, you may hack the
// console to intercept messages.
// check if a message is a Google Map's error message and respond
// accordingly
(function takeOverConsole() { // taken from http://tobyho.com/2012/07/27/taking-over-console-log/
var console = window.console
if (!console) return
function intercept(method) {
var original = console[method]
console[method] = function() {
// check message
if(arguments[0] && arguments[0].indexOf('OverQuotaMapError') !== -1) {
googleMapsCustomError();
}
if (original.apply) {
// Do this for normal browsers
original.apply(console, arguments)
} else {
// Do this for IE
var message = Array.prototype.slice.apply(arguments).join(' ')
original(message)
}
}
}
var methods = ['error']; // only interested in the console.error method
for (var i = 0; i < methods.length; i++)
intercept(methods[i])
}())
<!DOCTYPE html>
<div id="map-canvas"></div>
<script>
// Notice i am defining this within my html file, just to be sure that this function exists before the Google Maps API is loaded.
window.gm_authFailure = function() {
// remove the map div or maybe call another API to load map
// maybe display a useful message to the user
alert('Google maps failed to load!');
}
window.showMap = function() {
var lat = -34.397,
lng = 150.644;
initMap(window, window.google, lat, lng);
};
</script>
<!-- We are passing an invalid API key. Also notice that we have defined 'callback' as 'showMap' which means that when the Google API JavaScript library is finished loading it will call the 'showMap' function. -->
<script src="https://maps.googleapis.com/maps/api/js?key=INVALID_API_KEY&callback=showMap"
async defer></script>

Yes, JavaScript supports try-catch blocks. Here is a sample implementation for your code:
(function (window, google, lat, lng) {
var options = {
center: {
lat: Number(lat),
lng: Number(lng)
},
zoom: 5,
disableDefaultUI: true,
scrollwheel: true,
draggable: false
},
element = document.getElementById('map-canvas')
try {
var map = new google.maps.Map(element, options)
} catch (error) {
// handle error
console.log(error.message);
} finally {
// optional cleanup code
}
}(window, window.google, result[i]['latitude'], result[i]['longitude']));

As per google documentation.
If you exceed the usage limits you will get an OVER_QUERY_LIMIT status
code as a response.
This means that the web service will stop providing normal responses
and switch to returning only status code OVER_QUERY_LIMIT until more
usage is allowed again. This can happen:
Within a few seconds, if the error was received because your application sent too many requests per second.
Within the next 24 hours, if the error was received because your application sent too many requests per day. The daily quotas are
reset at midnight, Pacific Time.
Please refer this link. It would be helpful.

Passing HTML5 geolocation data to a variable

I'm really new to Javascript, and I'm trying to jump into it.
I want to have a script get geolocation data and pass it to a variable, and then have the information displayed in an alert.
I have a jsFiddle here: http://jsfiddle.net/yJrtR/
When I run it, I get an "undefined" in the alert box. Can someone help me with this?
Here is my code:
function lat() {
navigator.geolocation.getCurrentPosition(function (position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
}, function (error) {
console.log("Something went wrong: ", error);
});
}
function alert() {
var lat="";
var lon="";
lat();
alert("lat + lon");
}

There are several weird things in your code. Your fiddle is set to run onLoad, which means the functions you defined in your JavaScript won't be available globally - they'll be defined in the window.onload handler...which doesn't code outside of that to access them (especially inline event handlers). This is a perfect example of why not to use inline event handlers (even though the problem is really because of the jsFiddle settings).
So that means, when you call alert(); in your button's inline click handler, it calls the native window.alert() function, which brings up a dialog window. Since you pass nothing to it, it shows undefined. It's not actually calling your created alert function.
Also, since the getCurrentPosition method seems to be asynchronous, you should pass a callback function to lat, so that you can call it when it gets position.
Try this:
function lat(callback) {
navigator.geolocation.getCurrentPosition(function (position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
callback.call(null, lat, lon);
}, function (error) {
console.log("Something went wrong: ", error);
});
}
function getPosition() {
lat(function (latitude, longitude) {
alert("lat: " + latitude + ", lon: " + longitude);
});
}
http://jsfiddle.net/yJrtR/1/
UPDATE:
Per your comment, if you'd like it to be shown "live", you can use something like this:
window.onload = function () {
var latElement = document.getElementById("lat"),
lonElement = document.getElementById("lon"),
lastUpdatedElement = document.getElementById("last_updated"),
getPositionOptions = {
enableHighAccuracy: false,
timeout: 10000,
maximumAge: 0
},
getPos = function () {
console.log("getPos function called");
navigator.geolocation.getCurrentPosition(function (position) {
console.log("Successfully retrieved position: ", position);
var coords = position.coords;
latElement.innerHTML = coords.latitude;
lonElement.innerHTML = coords.longitude;
lastUpdatedElement.innerHTML = new Date(position.timestamp);
setTimeout(getPos, 5000);
}, function (error) {
console.log("Something went wrong retrieving position: ", error);
setTimeout(getPos, 5000);
}, getPositionOptions);
};
getPos();
};
with the following HTML (just to "simulate" the dialog you speak of):
<div id="dialog">
<div>Your latitude is: <span id="lat"></span></div>
<div>Your longitude is: <span id="lon"></span></div>
<div>Last Updated: <small id="last_updated"></small></div>
</div>
DEMO: http://jsfiddle.net/yJrtR/12/
So what this code does is from the time the window has loaded, it continually re-gets the geo position. There are special options you can pass to the getCurrentPosition, that I declared in getPositionOptions.
As I said before, the getCurrentPosition is asynchronous, so the position could be retrieved at any time after calling getCurrentPosition is called...that's what the callbacks are for. In the options object, I set a timeout - 10000 - that says "don't take any longer than 10 seconds to retrieve the position", and if it does, it will call the error callback. The maximumAge option makes sure it always tries to grab the current location (instead of using a cached version, within a certain period of time.
So when either callback is called (could be 1 second later, could be 20 seconds later...although we set a timeout of 10 seconds), it will update the HTML with the details, and then do it all again 5 seconds later - that's what the setTimeout is for. This is because if we continually tried to get the position (without any kind of delay), the page would be very busy getting the position. 5 second delays, or even up to 15, should be fine.
Reference:
https://developer.mozilla.org/en-US/docs/DOM/window.navigator.geolocation.getCurrentPosition
UPDATE:
There is a specific method for the geolocation feature that lets you watch the position, called watchPosition, doing exactly what I was trying to emulate, but more efficiently. You could try this:
window.onload = function () {
var latElement = document.getElementById("lat"),
lonElement = document.getElementById("lon"),
lastUpdatedElement = document.getElementById("last_updated"),
watchPositionOptions = {
enableHighAccuracy: false,
timeout: 10000,
maximumAge: 0
};
navigator.geolocation.watchPosition(function (position) {
console.log("Successfully retrieved position: ", position);
var coords = position.coords;
latElement.innerHTML = coords.latitude;
lonElement.innerHTML = coords.longitude;
lastUpdatedElement.innerHTML = new Date(position.timestamp);
}, function (error) {
console.log("Something went wrong retrieving position: ", error);
}, watchPositionOptions);
};
DEMO: http://jsfiddle.net/yJrtR/14/
Reference:
https://developer.mozilla.org/en-US/docs/DOM/window.navigator.geolocation.watchPosition?redirect=no