给定一个位置的经度和纬度，如何知道该位置的有效时区?
在大多数情况下，我们正在寻找IANA/Olson时区id，尽管有些服务可能只返回UTC偏移量或其他一些时区标识符。详细信息请阅读时区标签信息。
当前回答
如果您想使用geonames.org，请使用这段代码。(但是geonames.org有时很慢)
String get_time_zone_time_geonames(GeoPoint gp){
String erg = "";
double Longitude = gp.getLongitudeE6()/1E6;
double Latitude = gp.getLatitudeE6()/1E6;
String request = "http://ws.geonames.org/timezone?lat="+Latitude+"&lng="+ Longitude+ "&style=full";
URL time_zone_time = null;
InputStream input;
// final StringBuilder sBuf = new StringBuilder();
try {
time_zone_time = new URL(request);
try {
input = time_zone_time.openConnection().getInputStream();
final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
final StringBuilder sBuf = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sBuf.append(line);
}
} catch (IOException e) {
Log.e(e.getMessage(), "XML parser, stream2string 1");
} finally {
try {
input.close();
} catch (IOException e) {
Log.e(e.getMessage(), "XML parser, stream2string 2");
}
}
String xmltext = sBuf.toString();
int startpos = xmltext.indexOf("<geonames");
xmltext = xmltext.substring(startpos);
XmlPullParser parser;
try {
parser = XmlPullParserFactory.newInstance().newPullParser();
parser.setInput(new StringReader (xmltext));
int eventType = parser.getEventType();
String tagName = "";
while(eventType != XmlPullParser.END_DOCUMENT) {
switch(eventType) {
case XmlPullParser.START_TAG:
tagName = parser.getName();
break;
case XmlPullParser.TEXT :
if (tagName.equalsIgnoreCase("time"))
erg = parser.getText();
break;
}
try {
eventType = parser.next();
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (XmlPullParserException e) {
e.printStackTrace();
erg += e.toString();
}
} catch (IOException e1) {
e1.printStackTrace();
}
} catch (MalformedURLException e1) {
e1.printStackTrace();
}
return erg;
}
并将其用于:
GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
String Current_TimeZone_Time = get_time_zone_time_geonames(gp);
其他回答
好的，这是没有正确NTP时间的短版本:
String get_xml_server_reponse(String server_url){
URL xml_server = null;
String xmltext = "";
InputStream input;
try {
xml_server = new URL(server_url);
try {
input = xml_server.openConnection().getInputStream();
final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
final StringBuilder sBuf = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null)
{
sBuf.append(line);
}
}
catch (IOException e)
{
Log.e(e.getMessage(), "XML parser, stream2string 1");
}
finally {
try {
input.close();
}
catch (IOException e)
{
Log.e(e.getMessage(), "XML parser, stream2string 2");
}
}
xmltext = sBuf.toString();
} catch (IOException e1) {
e1.printStackTrace();
}
} catch (MalformedURLException e1) {
e1.printStackTrace();
}
return xmltext;
}
long get_time_zone_time_l(GeoPoint gp){
String raw_offset = "";
String dst_offset = "";
double Longitude = gp.getLongitudeE6()/1E6;
double Latitude = gp.getLatitudeE6()/1E6;
long tsLong = System.currentTimeMillis()/1000;
if (tsLong != 0)
{
// https://maps.googleapis.com/maps/api/timezone/xml?location=39.6034810,-119.6822510×tamp=1331161200&sensor=false
String request = "https://maps.googleapis.com/maps/api/timezone/xml?location="+Latitude+","+ Longitude+ "×tamp="+tsLong +"&sensor=false";
String xmltext = get_xml_server_reponse(request);
if(xmltext.compareTo("")!= 0)
{
int startpos = xmltext.indexOf("<TimeZoneResponse");
xmltext = xmltext.substring(startpos);
XmlPullParser parser;
try {
parser = XmlPullParserFactory.newInstance().newPullParser();
parser.setInput(new StringReader (xmltext));
int eventType = parser.getEventType();
String tagName = "";
while(eventType != XmlPullParser.END_DOCUMENT) {
switch(eventType) {
case XmlPullParser.START_TAG:
tagName = parser.getName();
break;
case XmlPullParser.TEXT :
if (tagName.equalsIgnoreCase("raw_offset"))
if(raw_offset.compareTo("")== 0)
raw_offset = parser.getText();
if (tagName.equalsIgnoreCase("dst_offset"))
if(dst_offset.compareTo("")== 0)
dst_offset = parser.getText();
break;
}
try {
eventType = parser.next();
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (XmlPullParserException e) {
e.printStackTrace();
erg += e.toString();
}
}
int ro = 0;
if(raw_offset.compareTo("")!= 0)
{
float rof = str_to_float(raw_offset);
ro = (int)rof;
}
int dof = 0;
if(dst_offset.compareTo("")!= 0)
{
float doff = str_to_float(dst_offset);
dof = (int)doff;
}
tsLong = (tsLong + ro + dof) * 1000;
}
return tsLong;
}
并将其用于:
GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
long Current_TimeZone_Time_l = get_time_zone_time_l(gp);
It's indeed important to recognize that this a more complicated problem than most would suspect. In practice many of us are also willing to accept a working set of code that works for "as many cases as possible", where at least its fatal issues can be identified and minimized collectively. So I post this with all of that and the spirit of the OP in mind. Finally, for practical value to others who are trying to convert GPS to timezone with the end goal of having a location-sensitive time object (and more importantly to help advance the quality of average implementations with time objects that follow from this wiki) here is what I generated in Python (please feel free to edit):
import pytz
from datetime import datetime
from tzwhere import tzwhere
def timezoned_unixtime(latitude, longitude, dt):
tzw = tzwhere.tzwhere()
timezone_str = tzw.tzNameAt(latitude, longitude)
timezone = pytz.timezone(timezone_str)
timezone_aware_datetime = timezone.localize(dt, is_dst=None)
unix_time = (timezone_aware_datetime - datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()
return unix_time
dt = datetime(year=2017, month=1, day=17, hour=12, minute=0, second=0)
print timezoned_unixtime(latitude=40.747854, longitude=-74.004733, dt=dt)
如果您想使用geonames.org，请使用这段代码。(但是geonames.org有时很慢)
String get_time_zone_time_geonames(GeoPoint gp){
String erg = "";
double Longitude = gp.getLongitudeE6()/1E6;
double Latitude = gp.getLatitudeE6()/1E6;
String request = "http://ws.geonames.org/timezone?lat="+Latitude+"&lng="+ Longitude+ "&style=full";
URL time_zone_time = null;
InputStream input;
// final StringBuilder sBuf = new StringBuilder();
try {
time_zone_time = new URL(request);
try {
input = time_zone_time.openConnection().getInputStream();
final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
final StringBuilder sBuf = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sBuf.append(line);
}
} catch (IOException e) {
Log.e(e.getMessage(), "XML parser, stream2string 1");
} finally {
try {
input.close();
} catch (IOException e) {
Log.e(e.getMessage(), "XML parser, stream2string 2");
}
}
String xmltext = sBuf.toString();
int startpos = xmltext.indexOf("<geonames");
xmltext = xmltext.substring(startpos);
XmlPullParser parser;
try {
parser = XmlPullParserFactory.newInstance().newPullParser();
parser.setInput(new StringReader (xmltext));
int eventType = parser.getEventType();
String tagName = "";
while(eventType != XmlPullParser.END_DOCUMENT) {
switch(eventType) {
case XmlPullParser.START_TAG:
tagName = parser.getName();
break;
case XmlPullParser.TEXT :
if (tagName.equalsIgnoreCase("time"))
erg = parser.getText();
break;
}
try {
eventType = parser.next();
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (XmlPullParserException e) {
e.printStackTrace();
erg += e.toString();
}
} catch (IOException e1) {
e1.printStackTrace();
}
} catch (MalformedURLException e1) {
e1.printStackTrace();
}
return erg;
}
并将其用于:
GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
String Current_TimeZone_Time = get_time_zone_time_geonames(gp);
There are several sources online that have geojson data for timezones (here's one, here's another) Use a geometry library to create polygon objects from the geojson coordinates (shapely [python], GEOS [c++], JTS [java], NTS [.net]). Convert your lat/lng to a point object (however your library represents that) and check if it intersects the timezone polygon. from shapely.geometry import Polygon, Point def get_tz_from_lat_lng(lat, lng): for tz, geojson in timezones.iteritems(): coordinates = geojson['features'][0]['geometry']['coordinates'] polygon = Polygon(coordinates) point = Point(lng, lat) if polygon.contains(point): return tz
node.js的这个解决方案怎么样 https://github.com/mattbornski/tzwhere
和它的Python对等体: https://github.com/pegler/pytzwhere
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