Android：マップビューのズームレベルを現在の場所から半径1 kmに設定するにはどうすればよいですか？
半径1kmにズームしたマップビューを設定したいのですが、どうすればわかりませんか？
文書によると、ズームレベル1は地球の赤道を256ピクセルにマッピングします。では、マップビューに半径1KMの領域が表示されるように設定する必要があるズームレベルを計算するにはどうすればよいですか？
更新：
いくつかのブログ投稿を読んだ後、次のコードを書きました。
private int calculateZoomLevel() {
double equatorLength = 6378140; // in meters
double widthInPixels = screenWidth;
double metersPerPixel = equatorLength / 256;
int zoomLevel = 1;
while ((metersPerPixel * widthInPixels) > 2000) {
metersPerPixel /= 2;
++zoomLevel;
}
Log.i("ADNAN", "zoom level = "+zoomLevel);
return zoomLevel;
}
アイデアは、まず、ズームレベル1でピクセルあたりのメートルを計算することです。Googleによると、256ピクセルを使用して地球の赤道を示しています。これで、後続のすべてのズームレベルが2レベルずつ拡大するため、各ズームレベルでピクセルあたりのメートルが半分になります。 ピクセルあたりのメートルと画面の幅の積が2000未満、つまり2 Kmになるズームレベルになるまでこれを行います。
しかし、ズームレベルが半径2Kmの地図を表示しているとは思わない。ここで私が間違っていることを誰かが教えてもらえますか？
次のコードは最終的に使用するものです。画面の幅と、ズームレベル1で地球の赤道の長さが256ピクセルで、その後のズームレベルごとに地球の赤道を表すのに必要なピクセル数が2倍になるという事実を考えると、次の関数は、画面がエリアを表示するズームレベルを返します2Km幅の。
private int calculateZoomLevel(int screenWidth) {
double equatorLength = 40075004; // in meters
double widthInPixels = screenWidth;
double metersPerPixel = equatorLength / 256;
int zoomLevel = 1;
while ((metersPerPixel * widthInPixels) > 2000) {
metersPerPixel /= 2;
++zoomLevel;
}
Log.i("ADNAN", "zoom level = "+zoomLevel);
return zoomLevel;
}
この答えは論理的であり、私はそれが機能していることがわかりますが、結果は正確ではありませんが、理由はわかりませんが、このアプローチに疲れており、この手法ははるかに正確です。
1）オブジェクト上に希望する半径の円を作成します
Circle circle = mGoogleMap.addCircle(new CircleOptions().center(new LatLng(latitude, longitude)).radius(getRadiusInMeters()).strokeColor(Color.RED));
circle.setVisible(true);
getZoomLevel(circle);
2）そのオブジェクトをこの関数に渡し、ズームレベルを設定します リンク
public int getZoomLevel(Circle circle) {
if (circle != null){
double radius = circle.getRadius();
double scale = radius / 500;
zoomLevel =(int) (16 - Math.log(scale) / Math.log(2));
}
return zoomLevel;
}
私は次のユーティリティを使用することになりました：
https://github.com/googlemaps/Android-maps-utils
ライブラリからクラスを抽出したため、ライブラリ全体は必要ありません。ズームレベルを設定する代わりに、境界を使用します。結果は同じです。
正確に1キロメートルを表示するコード：
animateToMeters(1000);
private void animateToMeters(int meters){
int mapHeightInDP = 200;
Resources r = getResources();
int mapSideInPixels = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mapHeightInDP, r.getDisplayMetrics());
LatLng point = new LatLng(0, 0);
LatLngBounds latLngBounds = calculateBounds(point, meters);
if(latLngBounds != null){
cameraUpdate = CameraUpdateFactory.newLatLngBounds(latLngBounds, mapSideInPixels, mapSideInPixels, MARKER_BOUNDS);
if(mMap != null)
mMap.animateCamera(cameraUpdate);
}
}
private LatLngBounds calculateBounds(LatLng center, double radius) {
return new LatLngBounds.Builder().
include(SphericalUtil.computeOffset(center, radius, 0)).
include(SphericalUtil.computeOffset(center, radius, 90)).
include(SphericalUtil.computeOffset(center, radius, 180)).
include(SphericalUtil.computeOffset(center, radius, 270)).build();
}
lib：から抽出された（わずかに変更された）クラス
public class SphericalUtil {
static final double EARTH_RADIUS = 6371009;
/**
* Returns hav() of distance from (lat1, lng1) to (lat2, lng2) on the unit sphere.
*/
static double havDistance(double lat1, double lat2, double dLng) {
return hav(lat1 - lat2) + hav(dLng) * cos(lat1) * cos(lat2);
}
/**
* Returns haversine(angle-in-radians).
* hav(x) == (1 - cos(x)) / 2 == sin(x / 2)^2.
*/
static double hav(double x) {
double sinHalf = sin(x * 0.5);
return sinHalf * sinHalf;
}
/**
* Computes inverse haversine. Has good numerical stability around 0.
* arcHav(x) == acos(1 - 2 * x) == 2 * asin(sqrt(x)).
* The argument must be in [0, 1], and the result is positive.
*/
static double arcHav(double x) {
return 2 * asin(sqrt(x));
}
private SphericalUtil() {}
/**
* Returns the heading from one LatLng to another LatLng. Headings are
* expressed in degrees clockwise from North within the range [-180,180).
* @return The heading in degrees clockwise from north.
*/
public static double computeHeading(LatLng from, LatLng to) {
// http://williams.best.vwh.net/avform.htm#Crs
double fromLat = toRadians(from.latitude);
double fromLng = toRadians(from.longitude);
double toLat = toRadians(to.latitude);
double toLng = toRadians(to.longitude);
double dLng = toLng - fromLng;
double heading = atan2(
sin(dLng) * cos(toLat),
cos(fromLat) * sin(toLat) - sin(fromLat) * cos(toLat) * cos(dLng));
return wrap(toDegrees(heading), -180, 180);
}
/**
* Returns the LatLng resulting from moving a distance from an Origin
* in the specified heading (expressed in degrees clockwise from north).
* @param from The LatLng from which to start.
* @param distance The distance to travel.
* @param heading The heading in degrees clockwise from north.
*/
public static LatLng computeOffset(LatLng from, double distance, double heading) {
distance /= EARTH_RADIUS;
heading = toRadians(heading);
// http://williams.best.vwh.net/avform.htm#LL
double fromLat = toRadians(from.latitude);
double fromLng = toRadians(from.longitude);
double cosDistance = cos(distance);
double sinDistance = sin(distance);
double sinFromLat = sin(fromLat);
double cosFromLat = cos(fromLat);
double sinLat = cosDistance * sinFromLat + sinDistance * cosFromLat * cos(heading);
double dLng = atan2(
sinDistance * cosFromLat * sin(heading),
cosDistance - sinFromLat * sinLat);
return new LatLng(toDegrees(asin(sinLat)), toDegrees(fromLng + dLng));
}
/**
* Returns the location of Origin when provided with a LatLng destination,
* meters travelled and original heading. Headings are expressed in degrees
* clockwise from North. This function returns null when no solution is
* available.
* @param to The destination LatLng.
* @param distance The distance travelled, in meters.
* @param heading The heading in degrees clockwise from north.
*/
public static LatLng computeOffsetOrigin(LatLng to, double distance, double heading) {
heading = toRadians(heading);
distance /= EARTH_RADIUS;
// http://lists.maptools.org/pipermail/proj/2008-October/003939.html
double n1 = cos(distance);
double n2 = sin(distance) * cos(heading);
double n3 = sin(distance) * sin(heading);
double n4 = sin(toRadians(to.latitude));
// There are two solutions for b. b = n2 * n4 +/- sqrt(), one solution results
// in the latitude outside the [-90, 90] range. We first try one solution and
// back off to the other if we are outside that range.
double n12 = n1 * n1;
double discriminant = n2 * n2 * n12 + n12 * n12 - n12 * n4 * n4;
if (discriminant < 0) {
// No real solution which would make sense in LatLng-space.
return null;
}
double b = n2 * n4 + sqrt(discriminant);
b /= n1 * n1 + n2 * n2;
double a = (n4 - n2 * b) / n1;
double fromLatRadians = atan2(a, b);
if (fromLatRadians < -PI / 2 || fromLatRadians > PI / 2) {
b = n2 * n4 - sqrt(discriminant);
b /= n1 * n1 + n2 * n2;
fromLatRadians = atan2(a, b);
}
if (fromLatRadians < -PI / 2 || fromLatRadians > PI / 2) {
// No solution which would make sense in LatLng-space.
return null;
}
double fromLngRadians = toRadians(to.longitude) -
atan2(n3, n1 * cos(fromLatRadians) - n2 * sin(fromLatRadians));
return new LatLng(toDegrees(fromLatRadians), toDegrees(fromLngRadians));
}
/**
* Returns the LatLng which lies the given fraction of the way between the
* Origin LatLng and the destination LatLng.
* @param from The LatLng from which to start.
* @param to The LatLng toward which to travel.
* @param fraction A fraction of the distance to travel.
* @return The interpolated LatLng.
*/
public static LatLng interpolate(LatLng from, LatLng to, double fraction) {
// http://en.wikipedia.org/wiki/Slerp
double fromLat = toRadians(from.latitude);
double fromLng = toRadians(from.longitude);
double toLat = toRadians(to.latitude);
double toLng = toRadians(to.longitude);
double cosFromLat = cos(fromLat);
double cosToLat = cos(toLat);
// Computes Spherical interpolation coefficients.
double angle = computeAngleBetween(from, to);
double sinAngle = sin(angle);
if (sinAngle < 1E-6) {
return from;
}
double a = sin((1 - fraction) * angle) / sinAngle;
double b = sin(fraction * angle) / sinAngle;
// Converts from polar to vector and interpolate.
double x = a * cosFromLat * cos(fromLng) + b * cosToLat * cos(toLng);
double y = a * cosFromLat * sin(fromLng) + b * cosToLat * sin(toLng);
double z = a * sin(fromLat) + b * sin(toLat);
// Converts interpolated vector back to polar.
double lat = atan2(z, sqrt(x * x + y * y));
double lng = atan2(y, x);
return new LatLng(toDegrees(lat), toDegrees(lng));
}
/**
* Returns distance on the unit sphere; the arguments are in radians.
*/
private static double distanceRadians(double lat1, double lng1, double lat2, double lng2) {
return arcHav(havDistance(lat1, lat2, lng1 - lng2));
}
/**
* Returns the angle between two LatLngs, in radians. This is the same as the distance
* on the unit sphere.
*/
static double computeAngleBetween(LatLng from, LatLng to) {
return distanceRadians(toRadians(from.latitude), toRadians(from.longitude),
toRadians(to.latitude), toRadians(to.longitude));
}
/**
* Returns the distance between two LatLngs, in meters.
*/
public static double computeDistanceBetween(LatLng from, LatLng to) {
return computeAngleBetween(from, to) * EARTH_RADIUS;
}
/**
* Returns the length of the given path, in meters, on Earth.
*/
public static double computeLength(List<LatLng> path) {
if (path.size() < 2) {
return 0;
}
double length = 0;
LatLng prev = path.get(0);
double prevLat = toRadians(prev.latitude);
double prevLng = toRadians(prev.longitude);
for (LatLng point : path) {
double lat = toRadians(point.latitude);
double lng = toRadians(point.longitude);
length += distanceRadians(prevLat, prevLng, lat, lng);
prevLat = lat;
prevLng = lng;
}
return length * EARTH_RADIUS;
}
/**
* Returns the area of a closed path on Earth.
* @param path A closed path.
* @return The path's area in square meters.
*/
public static double computeArea(List<LatLng> path) {
return abs(computeSignedArea(path));
}
/**
* Returns the signed area of a closed path on Earth. The sign of the area may be used to
* determine the orientation of the path.
* "inside" is the surface that does not contain the South Pole.
* @param path A closed path.
* @return The loop's area in square meters.
*/
public static double computeSignedArea(List<LatLng> path) {
return computeSignedArea(path, EARTH_RADIUS);
}
/**
* Returns the signed area of a closed path on a sphere of given radius.
* The computed area uses the same units as the radius squared.
* Used by SphericalUtilTest.
*/
static double computeSignedArea(List<LatLng> path, double radius) {
int size = path.size();
if (size < 3) { return 0; }
double total = 0;
LatLng prev = path.get(size - 1);
double prevTanLat = tan((PI / 2 - toRadians(prev.latitude)) / 2);
double prevLng = toRadians(prev.longitude);
// For each Edge, accumulate the signed area of the triangle formed by the North Pole
// and that Edge ("polar triangle").
for (LatLng point : path) {
double tanLat = tan((PI / 2 - toRadians(point.latitude)) / 2);
double lng = toRadians(point.longitude);
total += polarTriangleArea(tanLat, lng, prevTanLat, prevLng);
prevTanLat = tanLat;
prevLng = lng;
}
return total * (radius * radius);
}
/**
* Returns the signed area of a triangle which has North Pole as a vertex.
* Formula derived from "Area of a spherical triangle given two edges and the included angle"
* as per "Spherical Trigonometry" by Todhunter, page 71, section 103, point 2.
* See http://books.google.com/books?id=3uBHAAAAIAAJ&pg=PA71
* The arguments named "tan" are tan((pi/2 - latitude)/2).
*/
private static double polarTriangleArea(double tan1, double lng1, double tan2, double lng2) {
double deltaLng = lng1 - lng2;
double t = tan1 * tan2;
return 2 * atan2(t * sin(deltaLng), 1 + t * cos(deltaLng));
}
/**
* Wraps the given value into the inclusive-exclusive interval between min and max.
* @param n The value to wrap.
* @param min The minimum.
* @param max The maximum.
*/
static double wrap(double n, double min, double max) {
return (n >= min && n < max) ? n : (mod(n - min, max - min) + min);
}
/**
* Returns the non-negative remainder of x / m.
* @param x The operand.
* @param m The modulus.
*/
static double mod(double x, double m) {
return ((x % m) + m) % m;
}
}
Googleマップは、マイル/ピクセルに近いように動作するようです。ズーム= 13で、1マイル= 100ピクセル。 2マイル= 200ピクセル。各ズームレベルは2倍に増減します。したがって、ズーム14では1マイル= 200ピクセル、ズーム12では1マイル= 50ピクセルになります。
Android Google Mapsライブラリは浮動小数点ズームレベルを使用し、赤道からの緯度も考慮しているため、受け入れられた回答を変換してdouble値を返しました。
public static double getZoomForMetersWide (
final double desiredMeters,
final double mapWidth,
final double latitude )
{
final double latitudinalAdjustment = Math.cos( Math.PI * latitude / 180.0 );
final double arg = EQUATOR_LENGTH * mapWidth * latitudinalAdjustment / ( desiredMeters * 256.0 );
return Math.log( arg ) / Math.log( 2.0 );
}
余談ですが、Androidで最良の結果を得るには、ビューの実際のピクセル数を渡さないでください。ただし、デバイスのピクセル密度に合わせて寸法を調整します。
DisplayMetrics metrics = getResources().getDisplayMetrics();
float mapWidth = mapView.getWidth() / metrics.scaledDensity;
これが誰かを助けることを願っています。
ループを使用してズームレベルを計算するのは非常に単純です。数学を使う方がずっと良いです。
ここで関数（戻り値の型：float）
_public static double calcZoom(int visible_distance, int img_width)
{
// visible_distance -> in meters
// img_width -> in pixels
visible_distance = Math.abs(visible_distance);
double equator_length = 40075016; // in meters
// for an immage of 256 pixel pixel
double zoom256 = Math.log(equator_length/visible_distance)/Math.log(2);
// adapt the zoom to the image size
int x = (int) (Math.log(img_width/256)/Math.log(2));
double zoom = zoom256 + x;
return zoom;
}
_呼び出し例：
_public static void main(String[] args)
{
// computes the zoom for 1km=1000m for an image having 256 width
double zoom = MainClass.calcZoom(1000, 256);
System.out.println("zoom: " + String.valueOf(zoom));
return;
}
_ズームレベルを計算する数式は次のとおりです。
_equator_length = 40075016
zoom_level = logE(equator_length/distance)/logE(2) + logE(img_width/256)/logE(2)
// The zoom_level computed here is a float number.
_それはすべての人々です！ ：-）
[〜＃〜] attention [〜＃〜]：上記の解決策は、赤道の隣のズームレベルでのみ有効です。すべての緯度で機能するソリューションが必要な場合は、計算するズームレベルの同じ緯度での緯線の長さが必要です。 calcZoomメソッドは次のように変わります
_private double calcZoom(int visible_distance, int img_width, double atLatitude) {
// visible_distance -> in meters
// img_width -> in pixels
double parallel_length = this.calcParallelLegth(atLatitude); // in meters
// for an immage of 256 pixel pixel
zoom256 = Math.log(parallel_length/visible_distance))/Math.log(2)
// adapt the zoom to the image size
x = (int) Math.log(img_width/256)/Math.log(2)
zoom = zoom256 + x
return zoom;
}
_this.calcParallelLegth(atLatitude)は、atLatitude緯度の緯線の長さを返します。
ライブラリを使用して長さを自分で計算できます（Vincentyの式を使用することが望ましい）。
代わりに
そのようなライブラリがない場合（またはライブラリを検索しない場合、または機能する完全なコードが必要な場合）この回答の最後に、動作するコード全体がありますdouble calcParallelLegth(double atLatitude)の実装では、3％の許容範囲ですべての緯度で平行長のテーブル（Vincenty Formulaeを使用して計算）を使用します。
注意：
あなたが以下の説明を読み、式を理解する必要があります（または式ISが正しいか確認してください）
以下の式の説明：
簡単な方法でそれを置く！
問題を2つの部分に分けましょう。
パート1
256x256サイズの画像のズームを計算します
パート2
異なるサイズの画像にズームを適合させる
パート1の解決
画像サイズは256x256です。ズームレベル0は赤道全体を示します。
それ以降の各ズームレベルでは、その前の半分が表示されます。
赤道は40,075,016メートル long（WGS-84に準拠 （* 1） およびVincentyの式 （* 2） ）
_zoom=0 -> 40,075,016 / 1 = 40,075,016 meters visible Note: 2^0=1
zoom=1 -> 40,075,016 / 2 = 20,037,508 meters visible Note: 2^1=2
zoom=2 -> 40,075,016 / 4 = 10,018,754 meters visible Note: 2^2=4
zoom=3 -> 40,075,016 / 8 = 5,009,377 meters visible Note: 2^3=8
zoom=4 -> 40,075,016 / 16 = 2,504,688.5 meters visible Note: 2^4=16
zoom=5 -> 40,075,016 / 2^5 = 1,252,344.25 meters visible Note= 2^5=32
zoom=6 -> 40,075,016 / 2^6 = 636,172.125 meters visible Note= 2^6=64
...
zoom -> equator_length / 2^zoom = visible_distance
_上記でわかるように、後続の各ズームレベルでは、その前の半分が表示されます。
zoomは、望みのzoom_levelです。
visible_distanceは、画像が水平に表示されるメートル数です。
1 kmが必要な場合は、zoom with visible_distance = 10を計算する必要があります
ズーム式を見つけましょう。
ここで、数学が魔法になります（ "退屈な"魔法のもの）。
_ equator_length / 2^zoom = visible_distance ->
-> equator_length / visible_distance = 2^zoom ->
-> log2(equator_length / visible_distance) = log2(2^zoom) -> (*3)
-> log2(equator_length / visible_distance) = zoom*log2(2) -> (*4)
-> log2(equator_length / visible_distance) = zoom*1 -> (*5)
-> log2(equator_length / visible_distance) = zoom ->
-> logE(equator_length / visible_distance)/logE(2) = zoom -> (*6)
_256x256画像のズームレベルの式は次のとおりです。
_zoom256 = logE(equator_length/visible_distance) / logE(2)
_パート1完了!!
パート2の解決
ズームを希望の画像サイズに合わせます。
画像の幅が2倍になるたびに、赤道全体が1増加するのを見るためにズームが必要になりました。
例：
512x512の画像では、赤道全体を見るのに必要なズームは1です。1024x1024の画像では、赤道全体を見るのに必要なズームは2です。画像2048x2048では、赤道全体を見るのに必要なズームは3です。
それは言った
_width= 256 -> 256/256 = 1 -> zoom=0 (needed to see the whole equator)
width= 512 -> 512/256 = 2 -> zoom=1 (needed to see the whole equator)
width=1024 -> 1024/256 = 4 -> zoom=2 (needed to see the whole equator)
width=2048 -> 2048/256 = 8 -> zoom=3 (needed to see the whole equator)
width=4096 -> 4096/256 = 2^4 -> zoom=4 (needed to see the whole equator)
width=4096 -> 4096/256 = 2^5 -> zoom=5 (needed to see the whole equator)
_... width-> width/256 = 2 ^ x-> zoom = x（赤道全体を見る必要がある）
これは、（zoom_levelは
_- with an 512x512 image, the zoom needed is zoom256+1
- with an 1024x1024 image, the zoom needed is zoom256+2
- with an 2048x2048 image, the zoom needed is zoom256+3
...
- with an WIDTHxHEIGHT image, the zoom needed is zoom256+x
_xが必要なのは、望みの画像サイズにズームを適合させるためです。
だから、それはからのxの抽出の問題です
_width/256 = 2^x
_やってみましょう
_width/256 = 2^x ->
-> log2(width/256) = log2(2^x) -> (*3)
-> log2(width/256) = x * log2(2) -> (*4)
-> log2(width/256) = x * 1 -> (*5)
-> log2(width/256) = x ->
-> logE(width/256) / logE(2) = x -> (*6)
_これでx式ができました。
wIDTHxHEIGHT画像のズームレベルの式は次のとおりです。
_zoom = zoom256 + x
_したがって、512x512画像で1kmを表示したい場合は、
_zoom256 = logE(40075016/1000) / logE(2) = 15.29041547592718
x = logE(512/256) / logE(2) = 1
zoom = zoom256 + z = 15.29041547592718 + 1 = 16.29041547592718
_整数でなければならない場合
_zoom = floor(zoom) = 16
_完了！
_(*3) expr1=expr2 <-> log(expr1)=log(expr2)
(*4) logN(a^b) = b * logN(a)
(*5) logN(N) = 1
(*6) logN(expr) = log(expr)/log(N)
(*7) log(a/b) = log(a) - log(b)
_これは、緯度と経度の画像幅ごとにズームレベルを計算する完全なコードです。
_class MainClass
{
public static int getParallelLength(double atLatitude)
{
int FR_LAT = 0; // from latitude
int TO_LAT = 1; // to latidude
int PA_LEN = 2; // parallel length in meters)
int PC_ERR = 3; // percentage error
// fr_lat| to_lat | par_len| perc_err
double tbl[][] = {
{ 0.00, 12.656250000000000, 40075016, 2.410},
{12.66, 17.402343750000000, 39107539, 2.180},
{17.40, 22.148437500000000, 38252117, 2.910},
{22.15, 25.708007812500000, 37135495, 2.700},
{25.71, 28.377685546875000, 36130924, 2.330},
{28.38, 31.047363281250000, 35285940, 2.610},
{31.05, 33.717041015625000, 34364413, 2.890},
{33.72, 35.719299316406250, 33368262, 2.380},
{35.72, 37.721557617187500, 32573423, 2.560},
{37.72, 39.723815917968750, 31738714, 2.750},
{39.72, 41.726074218750000, 30865121, 2.950},
{41.73, 43.227767944335938, 29953681, 2.360},
{43.23, 44.729461669921875, 29245913, 2.480},
{44.73, 46.231155395507812, 28517939, 2.620},
{46.23, 47.732849121093750, 27770248, 2.760},
{47.73, 49.234542846679688, 27003344, 2.900},
{49.23, 50.360813140869141, 26217745, 2.290},
{50.36, 51.487083435058594, 25616595, 2.380},
{51.49, 52.613353729248047, 25005457, 2.480},
{52.61, 53.739624023437500, 24384564, 2.580},
{53.74, 54.865894317626953, 23754152, 2.690},
{54.87, 55.992164611816406, 23114464, 2.800},
{55.99, 57.118434906005859, 22465745, 2.920},
{57.12, 57.963137626647949, 21808245, 2.280},
{57.96, 58.807840347290039, 21309508, 2.360},
{58.81, 59.652543067932129, 20806081, 2.440},
{59.65, 60.497245788574219, 20298074, 2.520},
{60.50, 61.341948509216309, 19785597, 2.610},
{61.34, 62.186651229858398, 19268762, 2.700},
{62.19, 63.031353950500488, 18747680, 2.800},
{63.03, 63.876056671142578, 18222465, 2.900},
{63.88, 64.509583711624146, 17693232, 2.250},
{64.51, 65.143110752105713, 17293739, 2.320},
{65.14, 65.776637792587280, 16892100, 2.390},
{65.78, 66.410164833068848, 16488364, 2.460},
{66.41, 67.043691873550415, 16082582, 2.530},
{67.04, 67.677218914031982, 15674801, 2.610},
{67.68, 68.310745954513550, 15265074, 2.690},
{68.31, 68.944272994995117, 14853450, 2.780},
{68.94, 69.577800035476685, 14439980, 2.870},
{69.58, 70.211327075958252, 14024715, 2.970},
{70.21, 70.686472356319427, 13607707, 2.300},
{70.69, 71.161617636680603, 13293838, 2.360},
{71.16, 71.636762917041779, 12979039, 2.430},
{71.64, 72.111908197402954, 12663331, 2.500},
{72.11, 72.587053477764130, 12346738, 2.570},
{72.59, 73.062198758125305, 12029281, 2.640},
{73.06, 73.537344038486481, 11710981, 2.720},
{73.54, 74.012489318847656, 11391862, 2.800},
{74.01, 74.487634599208832, 11071946, 2.890},
{74.49, 74.962779879570007, 10751254, 2.980},
{74.96, 75.319138839840889, 10429810, 2.310},
{75.32, 75.675497800111771, 10188246, 2.370},
{75.68, 76.031856760382652, 9946280, 2.430},
{76.03, 76.388215720653534, 9703923, 2.500},
{76.39, 76.744574680924416, 9461183, 2.560},
{76.74, 77.100933641195297, 9218071, 2.640},
{77.10, 77.457292601466179, 8974595, 2.710},
{77.46, 77.813651561737061, 8730766, 2.790},
{77.81, 78.170010522007942, 8486593, 2.880},
{78.17, 78.526369482278824, 8242085, 2.970},
{78.53, 78.793638702481985, 7997252, 2.290},
{78.79, 79.060907922685146, 7813420, 2.350},
{79.06, 79.328177142888308, 7629414, 2.410},
{79.33, 79.595446363091469, 7445240, 2.470},
{79.60, 79.862715583294630, 7260900, 2.540},
{79.86, 80.129984803497791, 7076399, 2.600},
{80.13, 80.397254023700953, 6891742, 2.680},
{80.40, 80.664523243904114, 6706931, 2.750},
{80.66, 80.931792464107275, 6521972, 2.830},
{80.93, 81.199061684310436, 6336868, 2.920},
{81.20, 81.399513599462807, 6151624, 2.250},
{81.40, 81.599965514615178, 6012600, 2.310},
{81.60, 81.800417429767549, 5873502, 2.360},
{81.80, 82.000869344919920, 5734331, 2.420},
{82.00, 82.201321260072291, 5595088, 2.480},
{82.20, 82.401773175224662, 5455775, 2.550},
{82.40, 82.602225090377033, 5316394, 2.620},
{82.60, 82.802677005529404, 5176947, 2.690},
{82.80, 83.003128920681775, 5037435, 2.770},
{83.00, 83.203580835834146, 4897860, 2.850},
{83.20, 83.404032750986516, 4758224, 2.930},
{83.40, 83.554371687350795, 4618528, 2.260},
{83.55, 83.704710623715073, 4513719, 2.320},
{83.70, 83.855049560079351, 4408878, 2.370},
{83.86, 84.005388496443629, 4304006, 2.430},
{84.01, 84.155727432807907, 4199104, 2.490},
{84.16, 84.306066369172186, 4094172, 2.560},
{84.31, 84.456405305536464, 3989211, 2.630},
{84.46, 84.606744241900742, 3884223, 2.700},
{84.61, 84.757083178265020, 3779207, 2.770},
{84.76, 84.907422114629298, 3674165, 2.850},
{84.91, 85.057761050993577, 3569096, 2.940},
{85.06, 85.170515253266785, 3464003, 2.270},
{85.17, 85.283269455539994, 3385167, 2.320},
{85.28, 85.396023657813203, 3306318, 2.380},
{85.40, 85.508777860086411, 3227456, 2.440},
{85.51, 85.621532062359620, 3148581, 2.500},
{85.62, 85.734286264632829, 3069693, 2.570},
{85.73, 85.847040466906037, 2990793, 2.630},
{85.85, 85.959794669179246, 2911882, 2.710},
{85.96, 86.072548871452454, 2832959, 2.780},
{86.07, 86.185303073725663, 2754025, 2.860},
{86.19, 86.298057275998872, 2675080, 2.950},
{86.30, 86.382622927703778, 2596124, 2.280},
{86.38, 86.467188579408685, 2536901, 2.330},
{86.47, 86.551754231113591, 2477672, 2.390},
{86.55, 86.636319882818498, 2418437, 2.440},
{86.64, 86.720885534523404, 2359197, 2.510},
{86.72, 86.805451186228311, 2299952, 2.570},
{86.81, 86.890016837933217, 2240701, 2.640},
{86.89, 86.974582489638124, 2181446, 2.710},
{86.97, 87.059148141343030, 2122186, 2.790},
{87.06, 87.143713793047937, 2062921, 2.870},
{87.14, 87.228279444752843, 2003652, 2.950},
{87.23, 87.291703683531523, 1944378, 2.280},
{87.29, 87.355127922310203, 1899919, 2.340},
{87.36, 87.418552161088883, 1855459, 2.390},
{87.42, 87.481976399867563, 1810996, 2.450},
{87.48, 87.545400638646242, 1766531, 2.510},
{87.55, 87.608824877424922, 1722063, 2.580},
{87.61, 87.672249116203602, 1677594, 2.650},
{87.67, 87.735673354982282, 1633122, 2.720},
{87.74, 87.799097593760962, 1588648, 2.790},
{87.80, 87.862521832539642, 1544172, 2.880},
{87.86, 87.925946071318322, 1499695, 2.960},
{87.93, 87.973514250402332, 1455215, 2.290},
{87.97, 88.021082429486341, 1421854, 2.340},
{88.02, 88.068650608570351, 1388493, 2.400},
{88.07, 88.116218787654361, 1355130, 2.460},
{88.12, 88.163786966738371, 1321766, 2.520},
{88.16, 88.211355145822381, 1288401, 2.580},
{88.21, 88.258923324906391, 1255036, 2.650},
{88.26, 88.306491503990401, 1221669, 2.730},
{88.31, 88.354059683074411, 1188302, 2.800},
{88.35, 88.401627862158421, 1154934, 2.880},
{88.40, 88.449196041242431, 1121565, 2.970},
{88.45, 88.484872175555438, 1088195, 2.290},
{88.48, 88.520548309868445, 1063167, 2.350},
{88.52, 88.556224444181453, 1038139, 2.410},
{88.56, 88.591900578494460, 1013110, 2.470},
{88.59, 88.627576712807468, 988081, 2.530},
{88.63, 88.663252847120475, 963052, 2.590},
{88.66, 88.698928981433482, 938022, 2.660},
{88.70, 88.734605115746490, 912992, 2.740},
{88.73, 88.770281250059497, 887961, 2.810},
{88.77, 88.805957384372505, 862930, 2.900},
{88.81, 88.841633518685512, 837899, 2.980},
{88.84, 88.868390619420268, 812867, 2.300},
{88.87, 88.895147720155023, 794093, 2.360},
{88.90, 88.921904820889779, 775319, 2.420},
{88.92, 88.948661921624534, 756545, 2.480},
{88.95, 88.975419022359290, 737771, 2.540},
{88.98, 89.002176123094046, 718996, 2.610},
{89.00, 89.028933223828801, 700221, 2.680},
{89.03, 89.055690324563557, 681446, 2.750},
{89.06, 89.082447425298312, 662671, 2.830},
{89.08, 89.109204526033068, 643896, 2.910},
{89.11, 89.129272351584135, 625121, 2.250},
{89.13, 89.149340177135201, 611039, 2.300},
{89.15, 89.169408002686268, 596957, 2.350},
{89.17, 89.189475828237335, 582876, 2.410},
{89.19, 89.209543653788401, 568794, 2.470},
{89.21, 89.229611479339468, 554712, 2.530},
{89.23, 89.249679304890535, 540630, 2.600},
{89.25, 89.269747130441601, 526548, 2.670},
{89.27, 89.289814955992668, 512466, 2.740},
{89.29, 89.309882781543735, 498384, 2.820},
{89.31, 89.329950607094801, 484302, 2.900},
{89.33, 89.350018432645868, 470219, 2.990},
{89.35, 89.365069301809172, 456137, 2.310},
{89.37, 89.380120170972475, 445575, 2.370},
{89.38, 89.395171040135779, 435013, 2.420},
{89.40, 89.410221909299082, 424451, 2.480},
{89.41, 89.425272778462386, 413889, 2.550},
{89.43, 89.440323647625689, 403328, 2.610},
{89.44, 89.455374516788993, 392766, 2.680},
{89.46, 89.470425385952296, 382204, 2.760},
{89.47, 89.485476255115600, 371642, 2.840},
{89.49, 89.500527124278904, 361080, 2.920},
{89.50, 89.511815276151381, 350518, 2.260},
{89.51, 89.523103428023859, 342596, 2.310},
{89.52, 89.534391579896337, 334674, 2.360},
{89.53, 89.545679731768814, 326753, 2.420},
{89.55, 89.556967883641292, 318831, 2.480},
{89.56, 89.568256035513770, 310910, 2.540},
{89.57, 89.579544187386247, 302988, 2.610},
{89.58, 89.590832339258725, 295066, 2.680},
{89.59, 89.602120491131203, 287145, 2.750},
{89.60, 89.613408643003680, 279223, 2.830},
{89.61, 89.624696794876158, 271301, 2.910},
{89.62, 89.633162908780520, 263380, 2.250},
{89.63, 89.641629022684882, 257438, 2.300},
{89.64, 89.650095136589243, 251497, 2.360},
{89.65, 89.658561250493605, 245556, 2.410},
{89.66, 89.667027364397967, 239615, 2.470},
{89.67, 89.675493478302329, 233673, 2.540},
{89.68, 89.683959592206691, 227732, 2.600},
{89.68, 89.692425706111052, 221791, 2.670},
{89.69, 89.700891820015414, 215849, 2.750},
{89.70, 89.709357933919776, 209908, 2.830},
{89.71, 89.717824047824138, 203967, 2.910},
{89.72, 89.724173633252406, 198026, 2.250},
{89.72, 89.730523218680673, 193570, 2.300},
{89.73, 89.736872804108941, 189114, 2.350},
{89.74, 89.743222389537209, 184658, 2.410},
{89.74, 89.749571974965477, 180202, 2.470},
{89.75, 89.755921560393745, 175746, 2.530},
{89.76, 89.762271145822012, 171290, 2.600},
{89.76, 89.768620731250280, 166834, 2.670},
{89.77, 89.774970316678548, 162378, 2.740},
{89.77, 89.781319902106816, 157922, 2.820},
{89.78, 89.787669487535084, 153466, 2.900},
{89.79, 89.794019072963351, 149010, 2.990},
{89.79, 89.798781262034552, 144554, 2.310},
{89.80, 89.803543451105753, 141212, 2.360},
{89.80, 89.808305640176954, 137869, 2.420},
{89.81, 89.813067829248155, 134527, 2.480},
{89.81, 89.817830018319356, 131185, 2.540},
{89.82, 89.822592207390556, 127843, 2.610},
{89.82, 89.827354396461757, 124501, 2.680},
{89.83, 89.832116585532958, 121159, 2.750},
{89.83, 89.836878774604159, 117817, 2.830},
{89.84, 89.841640963675360, 114475, 2.910},
{89.84, 89.845212605478764, 111133, 2.250},
{89.85, 89.848784247282168, 108627, 2.300},
{89.85, 89.852355889085572, 106120, 2.360},
{89.85, 89.855927530888977, 103614, 2.410},
{89.86, 89.859499172692381, 101107, 2.470},
{89.86, 89.863070814495785, 98601, 2.540},
{89.86, 89.866642456299189, 96094, 2.600},
{89.87, 89.870214098102593, 93588, 2.670},
{89.87, 89.873785739905998, 91081, 2.750},
{89.87, 89.877357381709402, 88575, 2.830},
{89.88, 89.880929023512806, 86068, 2.910},
{89.88, 89.883607754865352, 83562, 2.240},
{89.88, 89.886286486217898, 81682, 2.300},
{89.89, 89.888965217570444, 79802, 2.350},
{89.89, 89.891643948922990, 77922, 2.410},
{89.89, 89.894322680275536, 76042, 2.470},
{89.89, 89.897001411628082, 74162, 2.530},
{89.90, 89.899680142980628, 72282, 2.600},
{89.90, 89.902358874333174, 70402, 2.660},
{89.90, 89.905037605685720, 68523, 2.740},
{89.91, 89.907716337038266, 66643, 2.820},
{89.91, 89.910395068390812, 64763, 2.900},
{89.91, 89.913073799743358, 62883, 2.980},
{89.91, 89.915082848257768, 61003, 2.310},
{89.92, 89.917091896772178, 59593, 2.360},
{89.92, 89.919100945286587, 58183, 2.420},
{89.92, 89.921109993800997, 56773, 2.480},
{89.92, 89.923119042315406, 55363, 2.540},
{89.92, 89.925128090829816, 53953, 2.610},
{89.93, 89.927137139344225, 52543, 2.680},
{89.93, 89.929146187858635, 51134, 2.750},
{89.93, 89.931155236373044, 49724, 2.830},
{89.93, 89.933164284887454, 48314, 2.910},
{89.93, 89.934671071273257, 46904, 2.250},
{89.93, 89.936177857659061, 45846, 2.300},
{89.94, 89.937684644044865, 44789, 2.360},
{89.94, 89.939191430430668, 43731, 2.410},
{89.94, 89.940698216816472, 42674, 2.470},
{89.94, 89.942205003202275, 41617, 2.540},
{89.94, 89.943711789588079, 40559, 2.600},
{89.94, 89.945218575973882, 39502, 2.670},
{89.95, 89.946725362359686, 38444, 2.740},
{89.95, 89.948232148745490, 37387, 2.820},
{89.95, 89.949738935131293, 36329, 2.900}
};
for(int r=0; r < tbl.length; r++)
{
double fromLat = tbl[r][FR_LAT];
double toLat = tbl[r][TO_LAT];
double atLat = atLatitude;
if(fromLat <= atLat && atLat < toLat)
{
double parallelLength = tbl[r][PA_LEN];
return (int)parallelLength;
}
}
return 0;
}
public static double calcZoom(int visible_distance, int img_width, double atLat)
{
// visible_distance -> in meters
// img_width -> in pixels
// atLat -> the latitude you want the zoom level
visible_distance = Math.abs(visible_distance);
double parallel_length = MainClass.getParallelLength(atLat); // in meters
// for an immage of 256 pixel pixel
double zoom256 = Math.log(parallel_length/visible_distance)/Math.log(2);
// adapt the zoom to the image size
int x = (int) (Math.log(img_width/256)/Math.log(2));
double zoom = zoom256 + x;
return zoom;
}
public static void main(String[] args)
{
int len;
double zoom;
// equator length
len = MainClass.getParallelLength(0);
System.out.println("parallel length at 0: " + String.valueOf(len));
// legth parallel at latitude 89.9 (near the north pole)
len = MainClass.getParallelLength(89.9);
System.out.println("parallel length at 89.9: " + String.valueOf(len));
// the zoom level needed to see 100km=100000m in a img having
// width 256 at equator latitude
zoom = MainClass.calcZoom(100000, 256, 0);
System.out.println("zoom (100km, width:256, lat:0): " + String.valueOf(zoom));
// the zoom level needed to see 100km=100000m in a img having
// width 512 at equator latitude
zoom = MainClass.calcZoom(100000, 512, 0);
System.out.println("zoom (100km, width:512, lat:0): " + String.valueOf(zoom));
// the zoom level needed to see 100km=100000m in a img having
// width 256 at latitude 60
zoom = MainClass.calcZoom(100000, 256, 60);
System.out.println("zoom (100km, width:256, lat:60): " + String.valueOf(zoom));
return;
}
}
_最終的な作業ソリューション：
public static void getZoomForMetersWide(GoogleMap googleMap, int mapViewWidth, LatLng latLngPoint, int desiredMeters) {
DisplayMetrics metrics = App.getAppCtx().getResources().getDisplayMetrics();
float mapWidth = mapViewWidth / metrics.density;
final int EQUATOR_LENGTH = 40075004;
final int TIME_ANIMATION_MILIS = 1500;
final double latitudinalAdjustment = Math.cos(Math.PI * latLngPoint.latitude / 180.0);
final double arg = EQUATOR_LENGTH * mapWidth * latitudinalAdjustment / (desiredMeters * 256.0);
double valToZoom = Math.log(arg) / Math.log(2.0);
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLngPoint, Float.valueOf(String.valueOf(valToZoom))), TIME_ANIMATION_MILIS , null);
}
追伸@sho回答と@Lionel Briandコメントを使用する
私はそれを見つけるための多くの方法があると確信しています私はこの技術を使用してズームレベルを計算します
mMap.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener() {
private float currentZoom = -1;
@Override
public void onCameraChange(CameraPosition position) {
if (position.zoom != currentZoom){
currentZoom = position.zoom; // here you get zoom level
Toast.makeText(this, "Zoom Value is : "+currentZoom, Toast.LENGTH_SHORT).show();
}
}
});