从地址获取纬度/经度

Question

如何使用iPhone SDK 3.x从用户输入的完整地址(街道,城市等)获取经度和纬度？

Answer 1

这是一个更新,更紧凑的unforgiven代码版本,它使用最新的v3 API:

- (CLLocationCoordinate2D) geoCodeUsingAddress:(NSString *)address
{
    double latitude = 0, longitude = 0;
    NSString *esc_addr =  [address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSString *req = [NSString stringWithFormat:@"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%@", esc_addr];
    NSString *result = [NSString stringWithContentsOfURL:[NSURL URLWithString:req] encoding:NSUTF8StringEncoding error:NULL];
    if (result) {
        NSScanner *scanner = [NSScanner scannerWithString:result];
        if ([scanner scanUpToString:@"\"lat\" :" intoString:nil] && [scanner scanString:@"\"lat\" :" intoString:nil]) {
            [scanner scanDouble:&latitude];
            if ([scanner scanUpToString:@"\"lng\" :" intoString:nil] && [scanner scanString:@"\"lng\" :" intoString:nil]) {
                [scanner scanDouble:&longitude];
            }
        }
    }
    CLLocationCoordinate2D center;
    center.latitude = latitude;
    center.longitude = longitude;
    return center;
}

它假设"位置"的坐标首先出现,例如在"视口"的坐标之前,因为它只取得它在"lng"和"lat"键下找到的第一个坐标.如果您担心这里使用的简单扫描技术,请随意使用合适的JSON扫描仪(例如SBJSON).

Answer 2

您可以使用谷歌地理编码此.它就像通过HTTP获取数据并解析它一样简单(它可以返回JSON KML,XML,CSV).

Answer 3

以下是从Google获取经纬度的类似解决方案.注意:此示例使用SBJson库,您可以在github上找到它:

+ (CLLocationCoordinate2D) geoCodeUsingAddress: (NSString *) address
{
    CLLocationCoordinate2D myLocation; 

// -- modified from the stackoverflow page - we use the SBJson parser instead of the string scanner --

        NSString       *esc_addr = [address stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
        NSString            *req = [NSString stringWithFormat: @"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%@", esc_addr];
    NSDictionary *googleResponse = [[NSString stringWithContentsOfURL: [NSURL URLWithString: req] encoding: NSUTF8StringEncoding error: NULL] JSONValue];

    NSDictionary    *resultsDict = [googleResponse valueForKey:  @"results"];   // get the results dictionary
    NSDictionary   *geometryDict = [   resultsDict valueForKey: @"geometry"];   // geometry dictionary within the  results dictionary
    NSDictionary   *locationDict = [  geometryDict valueForKey: @"location"];   // location dictionary within the geometry dictionary

// -- you should be able to strip the latitude & longitude from google's location information (while understanding what the json parser returns) --

    DLog (@"-- returning latitude & longitude from google --");

    NSArray *latArray = [locationDict valueForKey: @"lat"]; NSString *latString = [latArray lastObject];     // (one element) array entries provided by the json parser
    NSArray *lngArray = [locationDict valueForKey: @"lng"]; NSString *lngString = [lngArray lastObject];     // (one element) array entries provided by the json parser

     myLocation.latitude = [latString doubleValue];     // the json parser uses NSArrays which don't support "doubleValue"
    myLocation.longitude = [lngString doubleValue];

    return myLocation;
}