使用Google地图SDK在地图上绘制错误多段线 [英] Wrong polyline drawing on map with Google Maps SDK

问题描述

我正在尝试使用Google地图SDK在我的地图上绘制路线。
这个是我调用的URL，我解析了对坐标数组的JSON响应：

  id jsonResponse = [NSJSONSerialization JSONObjectWithData：responseObject options：NSJSONReadingMutableContainers error：nil]; 
 
 int points_count = 0; 
 points_count = [[[[[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps] count]; 
 
 NSArray * steps = nil; 
 if（points_count&& [[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] count]）
 {
 steps = [[ [[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps]; 
} 
 
 NSMutableArray * coordinates = [[NSMutableArray alloc] initWithCapacity：points_count]; 
 for（int i = 0; i< points_count; i ++）
 {
 NSDictionary * start; 
 NSDictionary *完成; 
 
 double st_lat = [[[[steps [objectAtIndex：i] objectForKey：@start_location] valueForKey：@lat] doubleValue]; 
 double st_lon = [[[[steps [objectAtIndex：i] objectForKey：@start_location] valueForKey：@lng] doubleValue]; 
 
 if（st_lat> 0.0f& st_lon> 0.0f）
 {
 start = @ {@latitude：[NSNumber numberWithDouble：st_lat]， @longitude：[NSNumber numberWithDouble：st_lon]}; 
} 
 
 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）
 {
 finish = @ {@latitude：[NSNumber numberWithDouble：end_lat]， @longitude：[NSNumber numberWithDouble：end_lon]}; 
} 
 
 [坐标addObject：@ {@start：start，@finish：finish}]; 
} 
  

比使用此方法绘制地图视图：

  GMSMutablePath * path = [GMSMutablePath path]; 
 for（NSDictionary * d in directions）
 {
 NSDictionary * start = d [@start]; 
 NSDictionary * finish = d [@finish]; 
 
 CLLocationCoordinate2D c_start = CLLocationCoordinate2DMake（[start [@latitude] doubleValue]，[start [@longitude] doubleValue]）; 
 CLLocationCoordinate2D c_finish = CLLocationCoordinate2DMake（[finish [@latitude] doubleValue]，[finish [@longitude] doubleValue]）; 
 
 [path addCoordinate：c_start]; 
 [path addCoordinate：c_finish]; 
} 
 
 GMSPolyline * line = [GMSPolyline polylineWithPath：path]; 
 line.strokeColor = [UIColor redColor]; 
 line.strokeWidth = 2.0f; 
 line.map = self.mapView; 
  

我在这里做错了什么？

解决方案

所以问题是我用 start_location 和 end_location 而不是 polyline - > points 。修正了我的代码：

请求URL例如： https://maps.googleapis.com/maps/api/directions/json？来源= 40.716072，-74.008836和目的地= 40.697545，-73.983892& sensor = false& waypoints = optimize：true& mode = driving

  id jsonResponse = [NSJSONSerialization JSONObjectWithData：responseObject options：NSJSONReadingMutableContainers error：nil]; 
 
 int points_count = 0; 
 points_count = [[[[[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps] count]; 
 
 NSArray * steps = nil; 
 if（points_count&& [[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] count]）
 {
 steps = [[ [[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps]; 
} 
 
 NSMutableArray * coordinates = [[NSMutableArray alloc] initWithCapacity：points_count]; 
 for（int i = 0; i< points_count; i ++）
 {
 NSString * toDecode = [[[steps objectAtIndex：i] objectForKey：@polyline] valueForKey：@点]; 
 NSArray * locations = [AppUtils decodePolylineWithString：toDecode]; 
 
 for（int i = 0; i< locations.count; i ++）
 {
 if（i！= locations.count  -  1）{
 CLLocation * start = [locations objectAtIndex：i]; 
 CLLocation * finish = [locations objectAtIndex：i + 1]; 
 [坐标addObject：@ {@start：start，@finish：finish}]; 
} 
} 
} 
 
 GMSMutablePath * path = [GMSMutablePath path]; 
 for（NSDictionary * d in directions）
 {
 CLLocation * start = d [@start]; 
 CLLocation * finish = d [@finish]; 
 
 [path addCoordinate：start.coordinate]; 
 [path addCoordinate：finish.coordinate]; 
} 
 
 GMSPolyline * line = [GMSPolyline polylineWithPath：path]; 
 line.strokeColor = [UIColor redColor]; 
 line.strokeWidth = 2.0f; 
 line.map = self.mapView; 
 
 $ b +（NSArray *）decodePolylineWithString :( NSString *）encodedString 
 {
 NSMutableArray * coordinates = [NSMutableArray array]; 
 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）<<转移; 
 shift + = 5; 
} while（byte> = 0x20）; （res& 1）？〜（res>> 1）：（res>> 1））; 
 
 float deltaLat = 
 latitude + = deltaLat; 
 
 shift = 0; 
 res = 0; 
 
 do {
 byte = bytes [idx ++]  -  0x3F; 
 res | =（byte& 0x1F）<<转移; 
 shift + = 5; 
} while（byte> = 0x20）; （res& 1）？〜（res>> 1）：（res>> 1））; 
 
 float deltaLon = 
 longitude + = deltaLon; 
 
 float finalLat =纬度* 1E-5; 
 float finalLon = longitude * 1E-5; 
 
 CLLocationCoordinate2D coord = CLLocationCoordinate2DMake（finalLat，finalLon）; 
 coords [coordIdx ++] = coord; 
 CLLocation * location = [[CLLocation alloc] initWithLatitude：finalLat longitude：finalLon]; 
 [coordinates addObject：location]; 
 
 if（coordIdx == count）{
 NSUInteger newCount = count + 10; 
 coords = realloc（coords，newCount * sizeof（CLLocationCoordinate2D））; 
 count = newCount; 
} 
} 
 
 free（coords）; 
返回坐标; 
} 
  

我知道这有点肮脏，但这很有效，而且效果很好。

享受。

I'm trying to draw route on my map using Google Maps SDK. This is the URL that i'm calling and I parse the JSON response to array of coordinates:

    id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];

    int points_count = 0;
    points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];

    NSArray *steps = nil;
    if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
    {
        steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
    }

    NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
    for (int i = 0; i < points_count; i++)
    {
        NSDictionary *start;
        NSDictionary *finish;

        double st_lat = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lat"] doubleValue];
        double st_lon = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lng"] doubleValue];

        if (st_lat > 0.0f && st_lon > 0.0f)
        {
            start = @{ @"latitude" : [NSNumber numberWithDouble:st_lat], @"longitude" : [NSNumber numberWithDouble:st_lon] };
        }

        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)
        {
            finish = @{ @"latitude" : [NSNumber numberWithDouble:end_lat], @"longitude" : [NSNumber numberWithDouble:end_lon] };
        }

        [coordinates addObject:@{ @"start" : start, @"finish" : finish }];
    }

And than drawing on the map view with this method:

GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
    NSDictionary *start = d[@"start"];
    NSDictionary *finish = d[@"finish"];

    CLLocationCoordinate2D c_start = CLLocationCoordinate2DMake([start[@"latitude"] doubleValue], [start[@"longitude"] doubleValue]);
    CLLocationCoordinate2D c_finish = CLLocationCoordinate2DMake([finish[@"latitude"] doubleValue], [finish[@"longitude"] doubleValue]);

    [path addCoordinate:c_start];
    [path addCoordinate:c_finish];
}

GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;

Why it is drawing like that and not going into the street it self?

What am I doing wrong here?

解决方案

So the problem was that I used the start_location and end_location instead of the polyline -> points. Fixed my code into this:

Request URL for example: https://maps.googleapis.com/maps/api/directions/json?origin=40.716072,-74.008836&destination=40.697545,-73.983892&sensor=false&waypoints=optimize:true&mode=driving

id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];

int points_count = 0;
points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];

NSArray *steps = nil;
if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
{
    steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
}

NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
for (int i = 0; i < points_count; i++)
{
    NSString *toDecode = [[[steps objectAtIndex:i] objectForKey:@"polyline"] valueForKey:@"points"];
    NSArray *locations = [AppUtils decodePolylineWithString:toDecode];

    for (int i = 0 ; i < locations.count ; i++)
    {
        if (i != locations.count - 1) {
            CLLocation *start = [locations objectAtIndex:i];
            CLLocation *finish = [locations objectAtIndex:i + 1];
            [coordinates addObject:@{ @"start" : start, @"finish" : finish }];
        }
    }
}

GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
    CLLocation *start = d[@"start"];
    CLLocation *finish = d[@"finish"];

    [path addCoordinate:start.coordinate];
    [path addCoordinate:finish.coordinate];
}

GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;


+ (NSArray*)decodePolylineWithString:(NSString *)encodedString
{
    NSMutableArray *coordinates = [NSMutableArray array];
    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;
        CLLocation *location = [[CLLocation alloc] initWithLatitude:finalLat longitude:finalLon];
        [coordinates addObject:location];

        if (coordIdx == count) {
            NSUInteger newCount = count + 10;
            coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
            count = newCount;
        }
    }

    free(coords);
    return coordinates;
}

I know it's a little bit dirty, but that's work and it works great.

Enjoy.

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