如何在非Google地圖的地圖中顯示某些用戶位置？

Question

我正在制作一個將在地圖上顯示當前位置的應用程序，但是此地圖是圖像（不是Google地圖）。 我怎樣才能做到這一點？ 使用不是Google地圖的地圖。

我想知道是否有可能以某種方式將Google地圖坐標與我要使用的這張地圖相關聯，並使用核心位置獲取這些坐標。

有什么想法嗎？

Answer 1

1. 您的圖片必須經過地理參考。

2. 您將必須知道地圖的投影參數。

3. 如果圖像不在經度/緯度投影中，則必須將核心位置提供的坐標投影到地圖使用的相同投影中。

Answer 2

我對這個問題感到困惑； 緯度+經度坐標並非Google地圖唯一。 您會在同一頁面上同時擁有Google地圖和圖片嗎？ 還是只想顯示圖像？ Google還使用Static Maps API提供此類服務

Answer 3

這是我為FAI地球儀和WGS-84投影的緯度/經度轉換創建的一個類。 您可以使用基本地理點（例如：地圖的中心）進行初始化，並且它將計算該點與其他點之間的距離（以米為單位）。 如果您隨后知道地圖的米/像素分辨率，則可以輕松地將其轉換為像素值。

該課程沒有很多文檔，但是我知道您可以弄清楚。 它使用了我的另一類（向量），但是您應該能夠輕松地用CGPoint替換它。

注意：它不適用於小比例尺地圖。 假設有大比例尺地圖（例如，小於100公里的地圖），則可優化其快速計算時間。

.h文件：

//
//  Earth.h
//
//  Created by René Dekker on 01/10/2011.
//  Copyright 2011. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>
#import "Vector.h"

enum EarthModel {
    EarthModelFAI = 0,
    EarthModelWGS84 = 1
};

@interface Earth : NSObject {
    enum EarthModel theModel;
    double theLongitudeScale;
    double theLatitudeScale;
    CLLocationCoordinate2D baseLocation;
}

@property CLLocationCoordinate2D baseLocation;

+ (Earth *)earthModel:(enum EarthModel)model atLatitude:(double)baseLatitude;
- (void) rebaseAtLatitude:(double)baseLatitude;

+ (Earth *)earthAtLocation:(CLLocationCoordinate2D)location model:(enum EarthModel)model;
- (void) rebaseAtLocation:(CLLocationCoordinate2D)location;

- (Vector *) differenceBetween:(CLLocationCoordinate2D)first and:(CLLocationCoordinate2D)second;
- (double) distanceBetween:(CLLocationCoordinate2D)first and:(CLLocationCoordinate2D)second;
- (CLLocationCoordinate2D) addTo:(CLLocationCoordinate2D)location vector:(Vector *)vector;
- (double) addToLongitude:(double)longitude distance:(double)distance;
- (double) addToLatitude:(double)latitude distance:(double)distance;

- (Vector *) vectorFromBase:(CLLocationCoordinate2D)location;
- (double) distanceFromBase:(CLLocationCoordinate2D)location;
- (CLLocationCoordinate2D) addToBase:(Vector *)vector;

@end

.m文件：

//
//  Earth.m
//
//  Created by René Dekker on 01/10/2011.
//  Copyright 2011. All rights reserved.
//
// The information and formulas used in the WGS84 computations come mainly from:
// http://en.wikipedia.org/wiki/World_Geodetic_System
// http://en.wikipedia.org/wiki/Meridian_arc#Meridian_distance_on_the_ellipsoid
// http://www.holoscenes.com/cgi-bin/moin.cgi/Ellipsoid
// http://www.movable-type.co.uk/scripts/gis-faq-5.1.html
// http://williams.best.vwh.net/avform.htm
// 

#import "Earth.h"

#define WGS_EQUATOR_R   6378137.0
#define WGS_POLAR_R     6356752.314245
#define F               (1/298.257223563)
#define E2              (F * (2 - F))
#define FAI_R           6371000

@implementation Earth

double modTo(double x, double lower, double upper)
{
    double range = upper - lower;
    double result = fmod(x - lower, range);
    if (result < 0) {
        result += range;
    }
    return result + lower;
}


- (void) rebaseAtLatitude:(double)baseLatitude
{
    baseLatitude *= PI_DEGREE;
    if (theModel == EarthModelWGS84) {
        double sinLat = sin(baseLatitude);
        double factor = sqrt(1 - E2*sinLat*sinLat);
        theLatitudeScale = PI_DEGREE * WGS_EQUATOR_R * (1-E2) / pow(factor, 3);
        theLongitudeScale = PI_DEGREE * WGS_EQUATOR_R * cos(baseLatitude) / factor;
    } else {
        theLatitudeScale = PI_DEGREE * FAI_R;
        theLongitudeScale = PI_DEGREE * FAI_R * cos(baseLatitude);
    }
}

- (void) rebaseAtLocation:(CLLocationCoordinate2D)location
{
    baseLocation = location;
    [self rebaseAtLatitude:location.latitude];
}

- (CLLocationCoordinate2D) baseLocation
{
    return baseLocation;
}

- (void) setBaseLocation:(CLLocationCoordinate2D)location
{
    baseLocation = location;
    [self rebaseAtLatitude:location.latitude];
}

- (Earth *) initWithModel:(enum EarthModel)model atLocation:(CLLocationCoordinate2D)location
{
    if (!(self = [super init])) {
        return nil;
    }
    theModel = model;
    [self rebaseAtLocation:location];
    return self;
}

+ (Earth *)earthModel:(enum EarthModel)model atLatitude:(double)baseLatitude
{
    CLLocationCoordinate2D location = CLLocationCoordinate2DMake(baseLatitude, 0);
    return [[[Earth alloc] initWithModel:model atLocation:location] autorelease];
}

+ (Earth *)earthAtLocation:(CLLocationCoordinate2D)location model:(enum EarthModel)model
{
    return [[[Earth alloc] initWithModel:model atLocation:location] autorelease];
}

- (Vector *) differenceBetween:(CLLocationCoordinate2D)first and:(CLLocationCoordinate2D)second
{
    double dx = modTo(first.longitude - second.longitude, -180, 180) * theLongitudeScale;
    double dy = (first.latitude - second.latitude) * theLatitudeScale;
    return [Vector withX:dx y:dy];
}

- (double) distanceBetween:(CLLocationCoordinate2D)first and:(CLLocationCoordinate2D)second
{
    double dx = modTo(first.longitude - second.longitude, -180, 180) * theLongitudeScale;
    double dy = (first.latitude - second.latitude) * theLatitudeScale;
    return hypot(dx, dy);
}

- (CLLocationCoordinate2D) addTo:(CLLocationCoordinate2D)location vector:(Vector *)vector
{
    location.latitude += vector.y / theLatitudeScale;
    location.longitude += modTo(vector.x / theLongitudeScale, -180, 180);
    return location;
}

- (Vector *) vectorFromBase:(CLLocationCoordinate2D)location
{
    return [self differenceBetween:location and:baseLocation];
}

- (double) distanceFromBase:(CLLocationCoordinate2D)location
{
    return [self distanceBetween:location and:baseLocation];
}

- (CLLocationCoordinate2D) addToBase:(Vector *)vector
{
    return [self addTo:baseLocation vector:vector];
}

- (double) addToLongitude:(double)longitude distance:(double)distance
{
    return modTo(longitude + distance / theLongitudeScale, -180, 180);
}

- (double) addToLatitude:(double)latitude distance:(double)distance
{
    return latitude + distance / theLatitudeScale;
}

- (NSString *) description
{
    return NSStringFromCLLocationCoordinate2D(baseLocation);
}

@end