GoogleMap API为两点之间的方向提供了错误的坐标 [英] GoogleMap API Gives Wrong Coordinates for Direction between two Points
本文介绍了GoogleMap API为两点之间的方向提供了错误的坐标的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想在iOS 6.1上提供支持，所以我使用GoogleMap，了解iOS7的恢复情况。
我使用GoogleMap API来显示GoogleMap上两点之间的绘制方向。
使用下面的代码进行解析并获取坐标的步骤以在地图上绘制折线：
NSURL * url = [[NSURL alloc] initWithString：[str stringByAddingPercentEscapesUsingEncoding：NSUTF8StringEncoding]];
NSURLRequest * request = [NSURLRequest requestWithURL：url cachePolicy：NSURLRequestUseProtocolCachePolicy timeoutInterval：60.0];
NSData * data = [NSURLConnection sendSynchronousRequest：request returningResponse：nil error：nil];
NSError *错误;
NSDictionary * json = [NSJSONSerialization JSONObjectWithData：data options：kNilOptions error：& error];
NSArray * latestRoutes = [json objectForKey：@routes];
NSMutableDictionary * legs = [[[latestRoutes objectAtIndex：0] objectForKey：@legs] objectAtIndex：0];
NSArray * steps = [legs objectForKey：@steps];
NSString * startLocation，* endLocation，* totalDistance，* totalDuration;
CLLocationCoordinate2D startLoc，endLoc;
startLocation = [legs objectForKey：@start_address];
endLocation = [legs objectForKey：@end_address];
totalDistance = [[legs objectForKey：@distance] objectForKey：@text];
totalDuration = [[leg objectForKey：@duration] objectForKey：@text];
startLoc = CLLocationCoordinate2DMake（[[legs objectForKey：@start_location] objectForKey：@lat] doubleValue] [[[legs objectForKey：@start_location] objectForKey：@lng] doubleValue]） ;
endLoc = CLLocationCoordinate2DMake（[[[legs objectForKey：@end_location] objectForKey：@lat] doubleValue]，[[[legs objectForKey：@end_location] objectForKey：@lng] doubleValue]） ;
NSMutableDictionary * tempDict;
if（[steps count]！= 0）{
GMSMutablePath * path = [GMSMutablePath path];
for（int idx = 0; idx< [steps count] +2; idx ++）{
CLLocationCoordinate2D workingCoordinate;
if（idx == 0）{
workingCoordinate = startLoc;
[path addCoordinate：workingCoordinate];
else if（idx == [steps count] +1）{
workingCoordinate = endLoc;
[path addCoordinate：workingCoordinate];
$ {b
$ b workingCoordinate = CLLocationCoordinate2DMake（[[[[steps [objectAtIndex：idx-1] objectForKey：@start_location] objectForKey：@lat] floatValue] ，[[[steps objectAtIndex：idx-1] objectForKey：@start_location] objectForKey：@lng] floatValue]）;
[path addCoordinate：workingCoordinate];
}
tempDict = nil;
}
//根据点数组创建多段线。
GMSPolyline * rectangle = [GMSPolyline polylineWithPath：path];
rectangle.strokeWidth = 5.0;
rectangle.map = mapView_;
}
它只提供24个步骤，意味着只有24个坐标点创建并绘制Line on地图如下图所示：
你可以看到这条线路不在正确的道路上，所以我能做些什么来解决这个问题？
i也希望在地图上显示方向。
解决方案
下面的答案适用于两个位置之间的平滑路径@ABáo：
- （void）viewDidLoad {
/ /创建一个GMSCameraPosition，告诉地图显示
GMSCameraPosition * camera = [GMSCameraPosition cameraWithLatitude：21.718472 longitude：73.030422 zoom：6];
mapView_ = [GMSMapView mapWithFrame：CGRectZero camera：camera];
mapView_.delegate = self;
mapView_.myLocationEnabled = YES;
mapView_.settings.myLocationButton = YES;
mapView_.settings.indoorPicker = NO;
mapView_.settings.compassButton = YES;
self.view = mapView_;
NSString * str = @http://maps.googleapis.com/maps/api/directions/json?origin=Bharuch,gujarat&destination=vadodara,gujarat&sensor=false;
NSURL * url = [[NSURL alloc] initWithString：[str stringByAddingPercentEscapesUsingEncoding：NSUTF8StringEncoding]];
NSURLRequest * request = [NSURLRequest requestWithURL：url cachePolicy：NSURLRequestUseProtocolCachePolicy timeoutInterval：60.0];
NSData * data = [NSURLConnection sendSynchronousRequest：request returningResponse：nil error：nil];
NSError *错误;
NSDictionary * json = [NSJSONSerialization JSONObjectWithData：data options：kNilOptions error：& error];
NSArray * latestRoutes = [json objectForKey：@routes];
NSString * points = [[[latestRoutes objectAtIndex：0] objectForKey：@overview_polyline] objectForKey：@points];
@try {
// TODO：更好的解析。正则表达式？
NSArray * temp = [self decodePolyLine：[points mutableCopy]];
GMSMutablePath * path = [GMSMutablePath path];
（int idx = 0; idx< [temp count]; idx ++）
{
CLLocation * location = [temp objectAtIndex：idx];
[path addCoordinate：location.coordinate];
}
//根据点数组创建多段线。
GMSPolyline * rectangle = [GMSPolyline polylineWithPath：path];
rectangle.strokeWidth = 5.0;
rectangle.map = mapView_;
$ b @catch（NSException * e）{
// TODO：显示错误
}
}
- （NSMutableArray *）decodePolyLine：（NSMutableString *）编码{
[编码replaceOccurrencesOfString：@\\\\withString：@\\
options：NSLiteralSearch
range：NSMakeRange（0，[encoded length]）];
NSInteger len = [编码长度];
NSInteger index = 0;
NSMutableArray * array = [[NSMutableArray alloc] init];
NSInteger lat = 0;
NSInteger lng = 0;
while（index< len）{
NSInteger b;
NSInteger shift = 0;
NSInteger结果= 0;
do {
b = [encoded characterAtIndex：index ++] - 63;
result | =（b& 0x1f）<<转移;
shift + = 5;
} while（b> = 0x20）;
NSInteger dlat =（（result& 1）？〜（result>> 1）：（result>> 1））;
lat + = dlat;
shift = 0;
结果= 0;
do {
b = [encoded characterAtIndex：index ++] - 63;
result | =（b& 0x1f）<<转移;
shift + = 5;
} while（b> = 0x20）;
NSInteger dlng =（（result& 1）？〜（result>> 1）：（result>> 1））;
lng + = dlng;
NSNumber * latitude = [[NSNumber alloc] initWithFloat：lat * 1e-5];
NSNumber * longitude = [[NSNumber alloc] initWithFloat：lng * 1e-5];
printf（[％f，，[latitude doubleValue]）;
printf（％f），[longitude doubleValue]）;
CLLocation * loc = [[CLLocation alloc] initWithLatitude：[latitude floatValue] longitude：[longitude floatValue]];
[array addObject：loc];
}
返回数组;
}
您可以比较此代码的屏幕截图以前的截图，我用于问问题：
I am using GoogleMap API for showing draw direction between two points on GoogleMap.
i want to give support on iOS 6.1 so i use GoogleMap i know about iOS7 recover this.
using below code for parsing and get Steps for coordinates to draw polyline on Map:
NSString *str=@"http://maps.googleapis.com/maps/api/directions/json?origin=bharuch,gujarat&destination=vadodara,gujarat&sensor=false";
NSURL *url=[[NSURL alloc]initWithString:[str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSArray* latestRoutes = [json objectForKey:@"routes"];
NSMutableDictionary *legs=[[[latestRoutes objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0];
NSArray *steps=[legs objectForKey:@"steps"];
NSString *startLocation,*endLocation,*totalDistance,*totalDuration;
CLLocationCoordinate2D startLoc,endLoc;
startLocation = [legs objectForKey:@"start_address"];
endLocation = [legs objectForKey:@"end_address"];
totalDistance = [[legs objectForKey:@"distance"] objectForKey:@"text"];
totalDuration = [[legs objectForKey:@"duration"] objectForKey:@"text"];
startLoc=CLLocationCoordinate2DMake([[[legs objectForKey:@"start_location"] objectForKey:@"lat"] doubleValue], [[[legs objectForKey:@"start_location"] objectForKey:@"lng"] doubleValue]);
endLoc=CLLocationCoordinate2DMake([[[legs objectForKey:@"end_location"] objectForKey:@"lat"] doubleValue], [[[legs objectForKey:@"end_location"] objectForKey:@"lng"] doubleValue]);
NSMutableDictionary *tempDict;
if ([steps count]!=0) {
GMSMutablePath *path = [GMSMutablePath path];
for(int idx = 0; idx < [steps count]+2; idx++){
CLLocationCoordinate2D workingCoordinate;
if (idx==0) {
workingCoordinate=startLoc;
[path addCoordinate:workingCoordinate];
}
else if (idx==[steps count]+1){
workingCoordinate=endLoc;
[path addCoordinate:workingCoordinate];
}
else{
workingCoordinate=CLLocationCoordinate2DMake([[[[steps objectAtIndex:idx-1] objectForKey:@"start_location"] objectForKey:@"lat"] floatValue], [[[[steps objectAtIndex:idx-1] objectForKey:@"start_location"] objectForKey:@"lng"] floatValue]);
[path addCoordinate:workingCoordinate];
}
tempDict = nil;
}
// create the polyline based on the array of points.
GMSPolyline *rectangle = [GMSPolyline polylineWithPath:path];
rectangle.strokeWidth=5.0;
rectangle.map = mapView_;
}
its gives only 24 steps means only 24 Coordinates for create point and draw Line on Map which is shown as below image:
you can see that line is not on proper road so what can i do to solve this? i also want to show direction on map too.
解决方案
Below answer is for smooth path between two location with help of @A Báo:
-(void)viewDidLoad { // Create a GMSCameraPosition that tells the map to display the GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:21.718472 longitude:73.030422 zoom:6]; mapView_ = [GMSMapView mapWithFrame:CGRectZero camera:camera]; mapView_.delegate=self; mapView_.myLocationEnabled = YES; mapView_.settings.myLocationButton=YES; mapView_.settings.indoorPicker=NO; mapView_.settings.compassButton=YES; self.view = mapView_; NSString *str=@"http://maps.googleapis.com/maps/api/directions/json?origin=Bharuch,gujarat&destination=vadodara,gujarat&sensor=false"; NSURL *url=[[NSURL alloc]initWithString:[str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]; NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0]; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; NSError* error; NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error]; NSArray* latestRoutes = [json objectForKey:@"routes"]; NSString *points=[[[latestRoutes objectAtIndex:0] objectForKey:@"overview_polyline"] objectForKey:@"points"]; @try { // TODO: better parsing. Regular expression? NSArray *temp= [self decodePolyLine:[points mutableCopy]]; GMSMutablePath *path = [GMSMutablePath path]; for(int idx = 0; idx < [temp count]; idx++) { CLLocation *location=[temp objectAtIndex:idx]; [path addCoordinate:location.coordinate]; } // create the polyline based on the array of points. GMSPolyline *rectangle = [GMSPolyline polylineWithPath:path]; rectangle.strokeWidth=5.0; rectangle.map = mapView_; } @catch (NSException * e) { // TODO: show error } } -(NSMutableArray *)decodePolyLine: (NSMutableString *)encoded { [encoded replaceOccurrencesOfString:@"\\\\" withString:@"\\" options:NSLiteralSearch range:NSMakeRange(0, [encoded length])]; NSInteger len = [encoded length]; NSInteger index = 0; NSMutableArray *array = [[NSMutableArray alloc] init] ; NSInteger lat=0; NSInteger lng=0; while (index < len) { NSInteger b; NSInteger shift = 0; NSInteger result = 0; do { b = [encoded characterAtIndex:index++] - 63; result |= (b & 0x1f) << shift; shift += 5; } while (b >= 0x20); NSInteger dlat = ((result & 1) ? ~(result >> 1) : (result >> 1)); lat += dlat; shift = 0; result = 0; do { b = [encoded characterAtIndex:index++] - 63; result |= (b & 0x1f) << shift; shift += 5; } while (b >= 0x20); NSInteger dlng = ((result & 1) ? ~(result >> 1) : (result >> 1)); lng += dlng; NSNumber *latitude = [[NSNumber alloc] initWithFloat:lat * 1e-5] ; NSNumber *longitude = [[NSNumber alloc] initWithFloat:lng * 1e-5] ; printf("[%f,", [latitude doubleValue]); printf("%f]", [longitude doubleValue]); CLLocation *loc = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]] ; [array addObject:loc]; } return array; }
Screenshot of this code you can compare it with previous screenshot which i used in asking Question:
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