在谷歌地图静态api中绘制圆形路径
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【中文标题】在谷歌地图静态api中绘制圆形路径【英文标题】:Draw a circle path in google map static api 【发布时间】:2019-07-07 17:01:28 【问题描述】:我正在使用android中的地图静态api开发一个应用程序
这是业务逻辑,用这个位置从google静态api获取用户位置请求并围绕这个位置画一个圆圈
这是我正在使用的代码
https://maps.googleapis.com/maps/api/staticmap?center=29.31166,47.481766&zoom=7&size=600x300&maptype=roadmap&key=My Key
现在的问题是如何在它周围画一个圆圈,我搜索了它,发现它是使用路径完成的,但不明白如何获得该路径
【问题讨论】:
【参考方案1】:你只需要像Developers Guide一样绘制路径:
http://maps.googleapis.com/maps/api/staticmap?center=29.31166,47.48177&zoom=7&size=600x300&path=color:0x0000FFFF|weight:3|fillcolor:0x0000FF77|<FIRST_POINT_LAT>,<FIRST_POINT_LNG>|<SECOND_POINT_LAT>,<SECOND_POINT_LNG>|...|<LAST_POINT_LAT>,<LAST_POINT_LNG>&key=<YOUR_API_KEY>
<FIRST_POINT_LAT>,<FIRST_POINT_LNG>|<SECOND_POINT_LAT>,<SECOND_POINT_LNG>|...|<LAST_POINT_LAT>,<LAST_POINT_LNG>
是你的圆路径的坐标。对于它的计算,你可以使用这样的方法:
private List<LatLng> getCirclePoints(LatLng center, double radius)
List<LatLng> circlePoints = new ArrayList<>();
// convert center coordinates to radians
double lat_rad = Math.toRadians(center.latitude);
double lon_rad = Math.toRadians(center.longitude);
double dist = radius / 6378137;
// calculate circle path point for each 5 degrees
for (int deg = 0; deg < 360; deg += 5)
double rad = Math.toRadians(deg);
// calculate coordinates of next circle path point
double new_lat = Math.asin(Math.sin(lat_rad) * Math.cos(dist) + Math.cos(lat_rad) * Math.sin(dist) * Math.cos(rad));
double new_lon = lon_rad + Math.atan2(Math.sin(rad) * Math.sin(dist) * Math.cos(lat_rad), Math.cos(dist)
- Math.sin(lat_rad) * Math.sin(new_lat));
// convert new lat and lon to degrees
double new_lat_deg = Math.toDegrees(new_lat);
double new_lon_deg = Math.toDegrees(new_lon);
circlePoints.add(new LatLng(new_lat_deg, new_lon_deg));
return circlePoints;
您可以用这种方式格式化静态地图 API URL:
private String buildStaticApiUrlWithCircle(LatLng mapCenter, int zoom, int width, int height,
LatLng circleCenter, double circleRadius, int pathWeight, String pathColor, String fillColor)
List<LatLng> circlePoints =getCirclePoints(circleCenter, circleRadius);
StringBuilder url = new StringBuilder();
url.append("http://maps.googleapis.com/maps/api/staticmap?");
url.append(String.format("center=%8.5f,%8.5f", mapCenter.latitude, mapCenter.longitude));
url.append(String.format("&zoom=%d", zoom));
url.append(String.format("&size=%dx%d", width, height));
// set circle path properties
url.append(String.format("&path="));
url.append(String.format("color:%s", pathColor));
url.append(String.format("|weight:%d", pathWeight));
url.append(String.format("|fillcolor:%s", fillColor));
// add circle path points
for (LatLng point : circlePoints)
url.append(String.format("|%8.5f,%8.5f", point.latitude, point.longitude));
// add API key to URL
url.append(String.format("&key=%s", <YOUR_API_KEY>)));
return url.toString();
圆形路径和填充颜色应设置为String
"0xRRGGBBAA"
格式,其中RR
- 红色通道的值,GG
- 绿色通道的值,BB
- 蓝色通道的值和@ 987654334@ - alpha 通道的值(例如"0x0000FFFF"
- 纯蓝色不透明,"0xFF000077"
- 纯红色 50% 透明等等)。
当你这样使用buildStaticApiUrlWithCircle()
时:
...
int mapZoom = 7;
int mapWidth = 600;
int mapHeight = 300;
LatLng mapCenter = new LatLng(29.31166, 47.481766);
LatLng circleCenter = new LatLng(29.376297, 47.976379);
double circleRadiusMerers = 35000;
String circlePathColor = "0x0000FFFF";
String circleFillColor = "0x0000FF99";
String mapUrl = buildStaticApiUrlWithCircle(mapCenter, mapZoom, mapWidth, mapHeight,
circleCenter, circleRadiusMerers, 3, circlePathColor, circleFillColor);
try
Bitmap mapBitmap = new GetStaticMapAsyncTask().execute(mapUrl).get();
mMapImageView.setImageBitmap(mapBitmap);
catch (InterruptedException e)
e.printStackTrace();
catch (ExecutionException e)
e.printStackTrace();
...
GetStaticMapAsyncTask
在哪里:
private class GetStaticMapAsyncTask extends AsyncTask<String, Void, Bitmap>
protected void onPreExecute()
super.onPreExecute();
protected Bitmap doInBackground(String... params)
Bitmap bitmap = null;
HttpURLConnection connection = null;
try
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
int responseCode = connection.getResponseCode();
InputStream stream = connection.getInputStream();
bitmap = BitmapFactory.decodeStream(stream);
catch (MalformedURLException e)
e.printStackTrace();
catch (IOException e)
e.printStackTrace();
finally
if (connection != null)
connection.disconnect();
return bitmap;
@Override
protected void onPostExecute(Bitmap result)
super.onPostExecute(result);
你会得到类似的东西:
另外,您可以使用Google Maps Lite Mode 代替静态地图 API(Lite 模式支持绘制圆圈)。甚至,如果您需要在地图的中心精确绘制圆圈 - 直接在位图画布上绘制。例如,您可以这样修改GetStaticMapAsyncTask
的doInBackground()
:
protected Bitmap doInBackground(String... params)
Bitmap bitmap = null;
HttpURLConnection connection = null;
try
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
int responseCode = connection.getResponseCode();
InputStream stream = connection.getInputStream();
Bitmap mapBitmap = BitmapFactory.decodeStream(stream);
Paint locaionMarkerPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
locaionMarkerPaint.setColor(Color.BLUE);
bitmap = Bitmap.createBitmap(mapBitmap.getWidth(), mapBitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
canvas.drawBitmap(mapBitmap,0,0, null);
canvas.drawCircle(mapBitmap.getWidth()/ 2, mapBitmap.getHeight() / 2, 20, locaionMarkerPaint);
catch (MalformedURLException e)
e.printStackTrace();
catch (IOException e)
e.printStackTrace();
finally
if (connection != null)
connection.disconnect();
return bitmap;
【讨论】:
这似乎是一个很好的解决方案,我没有尝试过,我使用了静态图像并将其作为我的地图的掩码,但是您的解决方案鼓励我尝试,会尝试并获得回到你身边以上是关于在谷歌地图静态api中绘制圆形路径的主要内容,如果未能解决你的问题,请参考以下文章