geolocation

问题 We know that due to the infamous China GPS offset problem, GPS (WSG-84) map coordinates don't correspond exactly to the coordinate system that state-approved Chinese maps use (GCJ-02). The question is, how does one make sure that placing a marker via the Baidu Maps API at the coordinates reported by navigator.geolocation.getCurrentPosition() will match reality? Would the GPS chip of a device manufactured or approved for use in China return coordinates that don't match the actual position of a

问题 Disclaimer: Any API is NO OPTION for me because of the vast amounts of places I want to process. I know there are plenty of services out there but I'd like to have my own solution Ok, after this is said here my question :) There are platforms like OpenStreetMap and maybe others who are doing very well in bringing the world of maps into the open source community. What I need I have an address located anywhere in the world and I want to compute the latitude and longitude, elevation would be

问题 I am using the QML MapItemView component with a C++ QAbstractListModel -based model. The MapItemView is working fine when the model is reset, or whenever a new item is added or an existing item is removed. However, the MapItemView is not reflecting changes to already added items. I have first experienced this issue with Qt 5.4 but I still face it after updating to Qt 5.5 The following example shows the issue with 2 different models : a C++ model based on QAbstractListModel and a QML ListModel

问题 For example, I have a latitude and longitude in decimal format (as opposed to Degrees-Hours-Minutes like lat=44.1° 9.5' 30''). To search for nearby objects, I must specify the search "radius" as a rectangle with four values: north = 44.1; south = -9.9; east = -22.4; west = 55.2; Is there a formula or rule of thumb how to convert decimal lat/long values into a rectangular bounding box, such that the given latitude/longitude is in the center of that box? Must I fiddle around myself with a WGS84

问题 I've encountered a rather strange situation where the backend developer asked me to force the city name that is returned from performing a geolocation to be in a specific language? For instance have it return København instead of Copenhagen no matter what language the iOS is to. I couldn't find anything on the web regarding this. Your help will be much appreciated. Thanks 回答1: Not sure if this is the best and safest solution but you could temporarily change the locale while you make the

问题 I’m learning HTML5 and testing the new features on a Qt hybrid application. Now I’m working on a simple geolocation example but when I call navigator.geolocation.getCurrentPosition(displayLocation); it seems the QtWebKit does not support it, but acording to this http://trac.webkit.org/wiki/QtWebKitFeatures22 the version of QtWebKit that comes with Qt4.8.0 supports geolocation. This is the code I’m using: window.onload = function() { getMyLocation(); } function getMyLocation() { if(navigator

问题 I'm looking for a elegant solution that calculates the center between several latitude-longitude coordinates (for example, to simply center a map to the center of a google-maps polygon). Table: locations : id | city | latitude | longitude ----------------------------------------------- 1 | Berlin | 52.524268 | 13.406290 ----------------------------------------------- 2 | London | 51.508129 | -0.1280050 ----------------------------------------------- 3 | Hamburg | 53.551084 | 9.9936817 -------

问题 I am using npm package geolocation but I have also used logic such as if (navigator.geolocation) and I keep getting ReferenceError: navigator is not defined As such? var geo = function(){ //using Mr. Concolato's example function geolocation(){ if(geo.geolocation()){//blah navigator.geolocation.getCurrentPosition(coords) console.log(coords); } } } 来源： https://stackoverflow.com/questions/27573293/what-causes-node-to-return-navigator-is-not-defined

问题 I've got a bunch of "locations" - some are accurate (gaborone, botswana), some are geocodes (40.75,-73.997) and some are completely useless (#siliconcape). I need to find a way to run through the list and determine the City and Country of each string and geocode, and return nulls for the invalid locations. Is there some sort of library/service/api/method that can be used to determine whether or not a given string represents a valid geographical location? While accounting for typos, ordering

问题 From what I have read this takes some complicated Math that I am not good at. So, I am asking here. Does anyone have experience converting a MKMapPoint or CLLocationCoordinate2D to a UTM value? I found this resource (http://www.uwgb.edu/dutchs/usefuldata/UTMFormulas.HTM) but the math is overwhelming. 回答1: You could use one lib to do that, or analyze the code of one lib to understand the algorithm and do it yourself. This is a c++ lib that does the job: http://geographiclib.sourceforge.net