geolocation | 易学教程

Checking if Longitude/Latitude within Greater Toronto Area in R

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问题 I have a dataset of Longitude and Latitude values and I want to check whether they are in the Greater Toronto Area. Alternative, labeling them with the Closest Census Metropolitan would suffice as well. Is there a way to accomplish this, preferably using R? 回答1: Here is a working example of how to do this with the rgdal package. There are plenty of other ways to do this. I provided a link to where you can get a Toronto shape file if you do not already have one. If you have any questions

Help calculating X and Y from Latitude and Longitude in iPhone

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问题 I'm stuck into some kind of geolocation limbo using a custom map with iPhone. The problem is: I have an UIScrollView and an UIImageView with a image of a custom map for a fair, with all stand locations and so on. My biggest problem is that I intend to use geolocation in order to locate the person inside that map. The problem begins when I try to get the pixel location of a given latitude and longitude. I have several ground control points as reference and even managed to calculate the an

how to get latitude/longitude from one geo address using Qt c++ on windows?

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问题 Its is possible get the coordinates(latitude and longitude), of a geo location using just the geo address (country, state, city, street, etc...), on Qt c++? I know the libraries QGeoCoordinates, QGeoLocation and QGeoAddress, but i don´t know if is possible get coordinates from an address through them. Every help is welcome. 回答1: I needed some time to master this but finally I got it working. At first I tried the classes mentioned by you: QGeoAddress, QGeoLocation, QGeoCoordinate: // standard

How to get the marked speed limit of a road, out of longitude and latitude [closed]

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I know that is not a technical question, but I don't know where else to ask. Is there a way to get the marked speed limit of a road from google or bing maps? or any other web service? You cannot obtain this information from Bing Maps or Google Maps. Nor am I aware of any other webservices that provide this information (certainly not any free ones). Open Street Map ( http://osm.org ) has the ability for ways to be recorded with the maxspeed tag. You could download the OSM planet dataset and host it in a spatial database such as SQL Server 2012, then create your own web service to query the

How does IP geolocating work?

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I'm not looking for a service that does this. I'm just curious as to how geolocation works. Mapping IP addresses to geolocations is done via tables, where an IP maps to a particular location. This location, however, does't need to be accurate, since IP addresses don't carry any information about their locations, these are approximated . From http://en.wikipedia.org/wiki/Geolocation_software : The primary source for IP address data is the regional Internet registries which allocate and distribute IP addresses amongst organizations located in their respective service regions: American Registry

function fail never called if user declines to share geolocation in firefox

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So I have this javascript code. In safari and chrome, if user declines to share location, it goes to fail function as it should; however, in Firefox, it does not. Any helps appreciated. function initGeolocation() { if( navigator.geolocation ) { // Call getCurrentPosition with success and failure callbacks navigator.geolocation.getCurrentPosition( success, fail ); } else { alert("Sorry, your browser does not support geolocation services."); } } var map; function success(position) { var longIDText = document.getElementById('longID'); var latIDText = document.getElementById('latID'); longIDText

Storing user's location in DB and find the nearest users for him

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问题 I am trying to implement a user system, one of the system requirements is find other users that are near you. Location will be filtered by countries but not by cities, so users can get other users from the same country but from different city. The question is how to calculate distances between cities? It doesn't have to be 100% accurate but it have to give some priority for closer users. Will Google Geo location API will satisfy those requirements? What are the alternatives? Any idea how to

Android - Reliably getting the current location

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My app checks at a specific time whether a user is at a given location. I use the alarm manager to start a service that makes this call: locationManager.requestLocationUpdates(bestProvider, 0, 0, listener); And also checks: locationManager.getLastKnownLocation(bestProvider); But I'm having problems when running on a real device. For one thing, getLastKnownLocation is most likely the last place the GPS was on, which could be anywhere (i.e., it could be miles from the user's current location). So I'll just wait for requestLocationUpdates callbacks, and if they aren't there within two minutes,

Expected ratio of ServiceWorker instances to Geolocation Updates

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问题 EDIT: There is a new version of my Brotkrumen Web App in the same location. Most important design/proposed-specification change is that TravelManager subscription should now be Client specific. The TravelEvent must contain the intended Client.id (TravelEvent.source.id). This means that the UA must monitor and filter GeoLocation updates per client. I have also added new demo functionality such as a Trip Summary that is displayed when you press the "Arrive" button. The trip can also be replayed

Get country from coordinates?

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How to get country name in Android, If are known geo coordinates? How to make it the simplest way? Use Below Function for that. public void getAddress(double lat, double lng) { Geocoder geocoder = new Geocoder(HomeActivity.mContext, Locale.getDefault()); try { List<Address> addresses = geocoder.getFromLocation(lat, lng, 1); Address obj = addresses.get(0); String add = obj.getAddressLine(0); GUIStatics.currentAddress = obj.getSubAdminArea() + "," + obj.getAdminArea(); GUIStatics.latitude = obj.getLatitude(); GUIStatics.longitude = obj.getLongitude(); GUIStatics.currentCity= obj.getSubAdminArea(