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iPhone용 Objective-C에서 Google Directions API polylines 필드를 lat long 포인트로 디코딩하는 방법은 무엇입니까?
Google Directions API를 통해 얻은 길잡이 JSON에 대응하는 지도에 경로를 그리고 싶습니다.https://developers.google.com/maps/documentation/directions/start
계단 필드에서 위도와 경도를 추출하는 방법을 알아냈지만, 곡선 도로를 잘 따라가지 못합니다.필요한 것은 폴리라인 정보를 디코딩하는 것입니다.폴리라인 인코딩 방법에 대한 구글의 설명을 찾았습니다.https://developers.google.com/maps/documentation/utilities/polylinealgorithm
Android용 코드와 폴리라인 디코딩에 관한 Javascript를 찾았습니다.예를 들어 다음과 같습니다.
지도 보기 Google Directions API를 사용하여 길찾기 - 폴리선 디코딩
Android가 Google Directions를 가져오고 구문 분석합니다.
하지만 Objective-C 아이폰 코드에는 같은 것을 찾을 수 없습니다.누군가 도와주실 수 있나요?필요하다면 제가 직접 할 수 있지만, 이미 어딘가에서 이용할 수 있다면 분명히 시간을 절약할 수 있을 거예요.
편집: 여기서 중요한 것은 Base64 인코딩을 문자별로 디코딩할 수 있는 것입니다.좀 더 구체적으로 말하면, 구글에서 JSON에서 Base64 인코딩을 사용하여 인코딩된 다음과 같은 정보를 얻을 수 있습니다.
... "overview_polyline" : {
"points" : "ydelDz~vpN_@NO@QEKWIYIIO?YCS@WFGBEBICCAE?G@y@RKBEBEBAD?HTpB@LALALCNEJEFSP_@LyDv@aB\\GBMB"
},
...
주의: 이 질문은 Google Maps API v1에 대한 것입니다.v2에서는 GMSPollyLine polyLine을 사용하여 이 작업을 수행하는 것이 훨씬 쉽습니다.WithPath는 아래 답변의 수만큼 알려줍니다(@cdescours 덕분에).
만약 그것이 질문과 관련이 있다면 내 블로그에 링크하는 것이 규칙에 어긋나지 않기를 바라지만, 나는 이 문제를 과거에 해결했다.링크된 게시물의 독립형 답변:
@implementation MKPolyline (MKPolyline_EncodedString)
+ (MKPolyline *)polylineWithEncodedString:(NSString *)encodedString {
const char *bytes = [encodedString UTF8String];
NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
NSUInteger idx = 0;
NSUInteger count = length / 4;
CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D));
NSUInteger coordIdx = 0;
float latitude = 0;
float longitude = 0;
while (idx < length) {
char byte = 0;
int res = 0;
char shift = 0;
do {
byte = bytes[idx++] - 63;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1));
latitude += deltaLat;
shift = 0;
res = 0;
do {
byte = bytes[idx++] - 0x3F;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1));
longitude += deltaLon;
float finalLat = latitude * 1E-5;
float finalLon = longitude * 1E-5;
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon);
coords[coordIdx++] = coord;
if (coordIdx == count) {
NSUInteger newCount = count + 10;
coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
count = newCount;
}
}
MKPolyline *polyline = [MKPolyline polylineWithCoordinates:coords count:coordIdx];
free(coords);
return polyline;
}
@end
가장 쉽고 최선의 답은 프레임워크에서 Google이 제공하는 방법을 사용하는 것입니다.
[GMSPolyline polylineWithPath:[GMSPath pathFromEncodedPath:encodedPath]]
iOS에서 Google Map을 사용하여 폴리라인을 포함한 경로를 그리려면 Google 자체에서 폴리라인에서 GMSPath를 쉽게 가져올 수 있습니다.
GMSPath *pathFromPolyline = [GMSPath pathFromEncodedPath:polyLinePoints];
다음은 완전한 코드입니다.
+ (void)callGoogleServiceToGetRouteDataFromSource:(CLLocation *)sourceLocation toDestination:(CLLocation *)destinationLocation onMap:(GMSMapView *)mapView_{
NSString *baseUrl = [NSString stringWithFormat:@"http://maps.googleapis.com/maps/api/directions/json?origin=%f,%f&destination=%f,%f&sensor=false", sourceLocation.coordinate.latitude, sourceLocation.coordinate.longitude, destinationLocation.coordinate.latitude, destinationLocation.coordinate.longitude];
NSURL *url = [NSURL URLWithString:[baseUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSLog(@"Url: %@", url);
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
GMSMutablePath *path = [GMSMutablePath path];
NSError *error = nil;
NSDictionary *result = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
NSArray *routes = [result objectForKey:@"routes"];
NSDictionary *firstRoute = [routes objectAtIndex:0];
NSDictionary *leg = [[firstRoute objectForKey:@"legs"] objectAtIndex:0];
NSArray *steps = [leg objectForKey:@"steps"];
int stepIndex = 0;
CLLocationCoordinate2D stepCoordinates[1 + [steps count] + 1];
for (NSDictionary *step in steps) {
NSDictionary *start_location = [step objectForKey:@"start_location"];
stepCoordinates[++stepIndex] = [self coordinateWithLocation:start_location];
[path addCoordinate:[self coordinateWithLocation:start_location]];
NSString *polyLinePoints = [[step objectForKey:@"polyline"] objectForKey:@"points"];
GMSPath *polyLinePath = [GMSPath pathFromEncodedPath:polyLinePoints];
for (int p=0; p<polyLinePath.count; p++) {
[path addCoordinate:[polyLinePath coordinateAtIndex:p]];
}
if ([steps count] == stepIndex){
NSDictionary *end_location = [step objectForKey:@"end_location"];
stepCoordinates[++stepIndex] = [self coordinateWithLocation:end_location];
[path addCoordinate:[self coordinateWithLocation:end_location]];
}
}
GMSPolyline *polyline = nil;
polyline = [GMSPolyline polylineWithPath:path];
polyline.strokeColor = [UIColor grayColor];
polyline.strokeWidth = 3.f;
polyline.map = mapView_;
}];
}
+ (CLLocationCoordinate2D)coordinateWithLocation:(NSDictionary*)location
{
double latitude = [[location objectForKey:@"lat"] doubleValue];
double longitude = [[location objectForKey:@"lng"] doubleValue];
return CLLocationCoordinate2DMake(latitude, longitude);
}
Swift 3.0
let polyline = GMSPolyline(path: GMSPath.init(fromEncodedPath: encodedPolyline))
Python 구현
Objective-C에는 없지만 Google 지도에서 폴리라인 문자열을 해독하려면 이 스레드가 필요합니다.(나처럼) 다른 사람이 필요할 경우를 대비해 폴리라인 스트링을 디코딩하기 위한 Python 구현이 있습니다.이것은 Mapbox JavaScript 버전에서 이식된 것입니다. 자세한 내용은 내 repo 페이지를 참조하십시오.
def decode_polyline(polyline_str):
index, lat, lng = 0, 0, 0
coordinates = []
changes = {'latitude': 0, 'longitude': 0}
# Coordinates have variable length when encoded, so just keep
# track of whether we've hit the end of the string. In each
# while loop iteration, a single coordinate is decoded.
while index < len(polyline_str):
# Gather lat/lon changes, store them in a dictionary to apply them later
for unit in ['latitude', 'longitude']:
shift, result = 0, 0
while True:
byte = ord(polyline_str[index]) - 63
index+=1
result |= (byte & 0x1f) << shift
shift += 5
if not byte >= 0x20:
break
if (result & 1):
changes[unit] = ~(result >> 1)
else:
changes[unit] = (result >> 1)
lat += changes['latitude']
lng += changes['longitude']
coordinates.append((lat / 100000.0, lng / 100000.0))
return coordinates
- (MKPolyline *)polylineWithEncodedString:(NSString *)encodedString {
const char *bytes = [encodedString UTF8String];
NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
NSUInteger idx = 0;
NSUInteger count = length / 4;
CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D));
NSUInteger coordIdx = 0;
float latitude = 0;
float longitude = 0;
while (idx < length) {
char byte = 0;
int res = 0;
char shift = 0;
do {
byte = bytes[idx++] - 63;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1));
latitude += deltaLat;
shift = 0;
res = 0;
do {
byte = bytes[idx++] - 0x3F;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1));
longitude += deltaLon;
float finalLat = latitude * 1E-5;
float finalLon = longitude * 1E-5;
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon);
coords[coordIdx++] = coord;
if (coordIdx == count) {
NSUInteger newCount = count + 10;
coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
count = newCount;
}
}
MKPolyline *polyline = [MKPolyline polylineWithCoordinates:coords count:coordIdx];
free(coords);
return polyline;
}
- (MKPolygonRenderer *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
// MKPolygonRenderer *polylineView = [[MKPolygonRenderer alloc] initWithOverlay:overlay];
MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];
polylineView.strokeColor = [UIColor redColor];
polylineView.lineWidth = 4.0;
[self zoomToPolyLine:mapview polyline:overlay animated:YES];
return polylineView;
}
-(void)zoomToPolyLine: (MKMapView*)map polyline: (MKPolyline*)polyline animated: (BOOL)animated
{
[map setVisibleMapRect:[polyline boundingMapRect] edgePadding:UIEdgeInsetsMake(25.0, 25.0, 25.0, 25.0) animated:animated];
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
// NSLog(@"didUpdateToLocation: %@", newLocation);
CLLocation *currentLocation = newLocation;
if (currentLocation != nil) {
currlong = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.longitude];
currlt = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.latitude];
}
NSString *origin = [NSString stringWithFormat:@"%@%@%@",currlt,@",",currlong];
//I have just mention static location
NSString *drivein = @"23.0472963,72.52757040000006";
NSString *apikey = [NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/directions/json?origin=%@&destination=%@",origin,drivein];
NSURL *url = [NSURL URLWithString:apikey];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
NSURLResponse *response;
NSError *error;
NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
if(!error)
{
NSData *data = [responseString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *jsonResponse = [NSJSONSerialization JSONObjectWithData:data
options:kNilOptions
error:&error];
NSArray *routesArray = [jsonResponse objectForKey:@"routes"];
NSLog(@"route array %@",routesArray);
if ([routesArray count] > 0)
{
NSDictionary *routeDict = [routesArray objectAtIndex:0];
NSDictionary *routeOverviewPolyline = [routeDict objectForKey:@"overview_polyline"];
NSString *points = [routeOverviewPolyline objectForKey:@"points"];
MKPolyline *line = [self polylineWithEncodedString:points];
[mapview addOverlay:line];
}
}
MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(currentLocation.coordinate, 500, 500);
MKCoordinateRegion adjustedRegion = [mapview regionThatFits:viewRegion];
[mapview setRegion:adjustedRegion animated:YES];
mapview.showsUserLocation = YES;
MKPointAnnotation *point = [[MKPointAnnotation alloc] init];
point.coordinate = currentLocation.coordinate;
point.title = @"Your current Locations";
point.subtitle = @"You are here!";
[mapview addAnnotation:point];
[locationmanger stopUpdatingLocation];
}
길찾기 앱은 다음과 같습니다.keyPlace는 대상 객체입니다.
- (void)getDirections {
CLLocation *newLocation;// = currentUserLocation;
MKPointAnnotation *annotation = [[[MKPointAnnotation alloc] init] autorelease];
annotation.coordinate = CLLocationCoordinate2DMake(newLocation.coordinate.latitude, newLocation.coordinate.longitude);
annotation.title = @"You";
[mapView addAnnotation:annotation];
CLLocationCoordinate2D endCoordinate;
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/directions/json?origin=%f,%f&destination=%f,%f&sensor=false&mode=walking", newLocation.coordinate.latitude, newLocation.coordinate.longitude, keyPlace.lat, keyPlace.lon]];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request startSynchronous];
if ([[request.responseString.JSONValue valueForKey:@"status"] isEqualToString:@"ZERO_RESULTS"]) {
[[[[UIAlertView alloc] initWithTitle:@"Error"
message:@"Could not route path from your current location"
delegate:nil
cancelButtonTitle:@"Close"
otherButtonTitles:nil, nil] autorelease] show];
self.navigationController.navigationBar.userInteractionEnabled = YES;
return;
}
int points_count = 0;
if ([[request.responseString.JSONValue objectForKey:@"routes"] count])
points_count = [[[[[[request.responseString.JSONValue objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];
if (!points_count) {
[[[[UIAlertView alloc] initWithTitle:@"Error"
message:@"Could not route path from your current location"
delegate:nil
cancelButtonTitle:@"Close"
otherButtonTitles:nil, nil] autorelease] show];
self.navigationController.navigationBar.userInteractionEnabled = YES;
return;
}
CLLocationCoordinate2D points[points_count * 2];
int j = 0;
NSArray *steps = nil;
if (points_count && [[[[request.responseString.JSONValue objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
steps = [[[[[request.responseString.JSONValue objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
for (int i = 0; i < points_count; i++) {
double st_lat = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lat"] doubleValue];
double st_lon = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lng"] doubleValue];
//NSLog(@"lat lon: %f %f", st_lat, st_lon);
if (st_lat > 0.0f && st_lon > 0.0f) {
points[j] = CLLocationCoordinate2DMake(st_lat, st_lon);
j++;
}
double end_lat = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lat"] doubleValue];
double end_lon = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lng"] doubleValue];
if (end_lat > 0.0f && end_lon > 0.0f) {
points[j] = CLLocationCoordinate2DMake(end_lat, end_lon);
endCoordinate = CLLocationCoordinate2DMake(end_lat, end_lon);
j++;
}
}
MKPolyline *polyline = [MKPolyline polylineWithCoordinates:points count:points_count * 2];
[mapView addOverlay:polyline];
}
#pragma mark - MapKit
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
MKPinAnnotationView *annView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"currentloc"] autorelease];
annView.canShowCallout = YES;
annView.animatesDrop = YES;
return annView;
}
- (MKOverlayView *)mapView:(MKMapView *)mapView
viewForOverlay:(id<MKOverlay>)overlay {
MKPolylineView *overlayView = [[[MKPolylineView alloc] initWithOverlay:overlay] autorelease];
overlayView.lineWidth = 5;
overlayView.strokeColor = [UIColor purpleColor];
overlayView.fillColor = [[UIColor purpleColor] colorWithAlphaComponent:0.5f];
return overlayView;
}
VBA의 디코딩 코드가 필요한 경우는, 다음의 포토가 동작하고 있습니다.
Function decodeGeopoints(encoded)
decodeGeopoints = ""
' This code is a port to VBA from code published here:
' http://blog.synyx.de/2010/06/routing-driving-directions-on-android-part-1-get-the-route/
'//decoding
'List poly = new ArrayList();
'// replace two backslashes by one (some error from the transmission)
'encoded = encoded.replace("\\", "\");
encoded = Replace(encoded, "\\", "\")
'int index = 0, len = encoded.length();
Dim index As Long
index = 0
Dim leng As Long
leng = Len(encoded)
'int lat = 0, lng = 0;
Dim lat As Long
lat = 0
Dim lng As Long
lng = 0
'while (index < len) {
While (index < leng)
'int b, shift = 0, result = 0;
Dim b, shift, result As Long
b = 0
shift = 0
result = 0
'do {
Do
'b = encoded.charAt(index++) - 63;
index = index + 1
b = Asc(Mid(encoded, index, 1)) - 63
'result |= (b & 0x1f) << shift;
result = result Or ((b And 31) * (2 ^ shift))
'shift += 5;
shift = shift + 5
'} while (b >= 0x20);
Loop While (b >= 32)
'int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
Dim dlat As Long
If (result And 1) <> 0 Then
dlat = Not Int(result / 2)
Else
dlat = Int(result / 2)
End If
'lat += dlat;
lat = lat + dlat
'shift = 0;
shift = 0
'result = 0;
result = 0
'do {
Do
'b = encoded.charAt(index++) - 63;
index = index + 1
b = Asc(Mid(encoded, index, 1)) - 63
'result |= (b & 0x1f) << shift;
result = result Or ((b And 31) * (2 ^ shift))
'shift += 5;
shift = shift + 5
'} while (b >= 0x20);
Loop While (b >= 32)
'int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
Dim dlng As Long
If (result And 1) <> 0 Then
dlng = Not Int(result / 2)
Else
dlng = Int(result / 2)
End If
'lng += dlng;
lng = lng + dlng
'GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6), (int) (((double) lng / 1E5) * 1E6));
Dim myLat, myLng As Double
myLat = (lat / 100000)
'myLat = myLat * 1000000
myLng = (lng / 100000)
'myLng = myLng * 1000000
'poly.add(p);
decodeGeopoints = decodeGeopoints & Comma2Dot(myLng) & "," & Comma2Dot(myLat) & ",0 "
'}
Wend
End Function
구글 지도의 경우, 그것은 이미 간단한 방법을 가지고 있다.polylineWithPath그래서 저는 이 토막이 더 좋아요.
-(void)drawPathFrom:(CLLocation*)source toDestination:(CLLocation*)destination{
NSString *baseUrl = [NSString stringWithFormat:@"http://maps.googleapis.com/maps/api/directions/json?origin=%f,%f&destination=%f,%f&sensor=true", source.coordinate.latitude, source.coordinate.longitude, destination.coordinate.latitude, destination.coordinate.longitude];
NSURL *url = [NSURL URLWithString:[baseUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSLog(@"Url: %@", url);
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
if(!connectionError){
NSDictionary *result = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
NSArray *routes = [result objectForKey:@"routes"];
NSDictionary *firstRoute = [routes objectAtIndex:0];
NSString *encodedPath = [firstRoute[@"overview_polyline"] objectForKey:@"points"];
GMSPolyline *polyPath = [GMSPolyline polylineWithPath:[GMSPath pathFromEncodedPath:encodedPath]];
polyPath.strokeColor = [UIColor redColor];
polyPath.strokeWidth = 3.5f;
polyPath.map = _mapView;
}
}];
}
Swift 4.2 / Swift 5
let gmsPolyline = GMSPolyline(path: GMSPath(fromEncodedPath: encodedPolyline))
gmsPolyline.map = map
이건 내가 다시 생각해본 Sedate Alien의 대답이야.중복된 코드를 제거하고 수동으로 할당하는 대신 NSMutableData를 사용하기 위한 구현 세이브와 동일합니다.
@implementation MKPolyline (EncodedString)
+ (float)decodeBytes:(const char *)bytes atPos:(NSUInteger *)idx toValue:(float *)value {
char byte = 0;
int res = 0;
char shift = 0;
do {
byte = bytes[(*idx)++] - 0x3F;
res |= (byte & 0x1F) << shift;
shift += 5;
}
while (byte >= 0x20);
(*value) += ((res & 1) ? ~(res >> 1) : (res >> 1));
return (*value) * 1E-5;
}
+ (MKPolyline *)polylineWithEncodedString:(NSString *)encodedString {
const char *bytes = [encodedString UTF8String];
NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
NSUInteger idx = 0;
NSMutableData *data = [NSMutableData data];
float lat = 0;
float lon = 0;
CLLocationCoordinate2D coords = CLLocationCoordinate2DMake(0, 0);
while (idx < length) {
coords.latitude = [self decodeBytes:bytes atPos:&idx toValue:&lat];
coords.longitude = [self decodeBytes:bytes atPos:&idx toValue:&lon];
[data appendBytes:&coords length:sizeof(CLLocationCoordinate2D)];
}
return [MKPolyline polylineWithCoordinates:(CLLocationCoordinate2D *)data.bytes count:data.length / sizeof(CLLocationCoordinate2D)];
}
@end
다른 답변은 Apple Maps 사용인 것 같습니다.Google Maps를 사용하기 위해 @Sedate Alien의 훌륭한 카테고리를 수정해야 했습니다.
카테고리 변경
+ (GMSPolyline *)polylineWithEncodedString:(NSString *)encodedString {
const char *bytes = [encodedString UTF8String];
NSUInteger length = [encodedString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
NSUInteger idx = 0;
NSUInteger count = length / 4;
CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D));
NSUInteger coordIdx = 0;
float latitude = 0;
float longitude = 0;
while (idx < length) {
char byte = 0;
int res = 0;
char shift = 0;
do {
byte = bytes[idx++] - 63;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1));
latitude += deltaLat;
shift = 0;
res = 0;
do {
byte = bytes[idx++] - 0x3F;
res |= (byte & 0x1F) << shift;
shift += 5;
} while (byte >= 0x20);
float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1));
longitude += deltaLon;
float finalLat = latitude * 1E-5;
float finalLon = longitude * 1E-5;
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon);
coords[coordIdx++] = coord;
if (coordIdx == count) {
NSUInteger newCount = count + 10;
coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
count = newCount;
}
}
GMSMutablePath *path = [[GMSMutablePath alloc] init];
int i;
for (i = 0; i < coordIdx; i++)
{
[path addCoordinate:coords[i]];
}
GMSPolyline *polyline = [GMSPolyline polylineWithPath:path];
free(coords);
return polyline;
}
사용.
// Here I make the call to the Google Maps API to get the routes between two points...
....
// Get the encoded array of points.
NSString *points = routes[@"routes"][0][@"overview_polyline"][@"points"];
// Use the modified category to get a polyline from the points.
GMSPolyline *polyline = [GMSPolyline polylineWithEncodedString:points];
// Add the polyline to the map.
polyline.strokeColor = [UIColor redColor];
polyline.strokeWidth = 10.f;
polyline.map = theMapView;
}
이것을 신속히 실행하려고 하는 사람이 있다면, swift(2.3)에 맞춘 @RootCode의 회답은 다음과 같습니다.
let path = GMSMutablePath()
let steps = directionsToShowOnMap.steps
for (idx, step) in steps.enumerate() {
path.addCoordinate(coordinateFromJson(step["start_location"]))
if let polylinePoints = step["polyline"].string, subpath = GMSPath(fromEncodedPath: polylinePoints) {
for c in 0 ..< subpath.count() {
path.addCoordinate(subpath.coordinateAtIndex(c))
}
}
if idx == steps.count - 1 {
path.addCoordinate(coordinateFromJson(step["end_location"]))
}
}
let polyline = GMSPolyline(path: path)
polyline.strokeColor = UIColor.blueColor()
polyline.strokeWidth = 3
polyline.map = mapView
그 후:
private func coordinateFromJson(location: JSON) -> CLLocationCoordinate2D {
return CLLocationCoordinate2DMake(location["lat"].double!, location["lng"].double!)
}
언급URL : https://stackoverflow.com/questions/9217274/how-to-decode-the-google-directions-api-polylines-field-into-lat-long-points-in
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