从地址获取经度/纬度 [英] Get latitude/longitude from address

问题描述

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

How can I get latitude and longitude from a full address (street, city, etc.) input by the user, using the iPhone SDK 3.x?

推荐答案

这是Unforgiven代码的更新，更紧凑的版本，它使用最新的v3 API:

Here's an updated, more compact, version of unforgiven's code, which uses the latest 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;
}

假设位置"的坐标排在第一位，例如在视口"之前，因为它只需要在"lng"和"lat"键下找到的第一个坐标.如果您担心此处使用的这种简单扫描技术，请随时使用适当的JSON扫描器(例如SBJSON).

It makes the assumption that the coordinates for "location" come first, e.g. before those for "viewport", because it just takes the first coords it finds under the "lng" and "lat" keys. Feel free to use a proper JSON scanner (e.g. SBJSON) if you are worried about this simple scanning technique used here.

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