Introduction to geofence polygon drawing using Java to develop Amap API

Introduction to Geofence Polygon Drawing Using Java to Develop Amap API

Geofence is a technical means used to determine whether a geographical location is within a specified area and can be used in many scenarios. For example, motion trajectory analysis, electronic fence alarm, etc. The Amap API provides a polygon drawing function for geofences, which makes it easy to mark on the map and determine whether a certain location is within a specified area. The following will introduce how to use Java to develop the geofence polygon drawing function of the Amap API.

First of all, you need to introduce the Java SDK of Amap Map API. You can add the following dependencies in the project's pom.xml file:

<dependency>
  <groupId>com.amap.api</groupId>
  <artifactId>amap-java-sdk</artifactId>
  <version>1.4.0</version>
</dependency>

Then, introduce relevant classes and interfaces into the code:

import com.amap.api.maps.AMap;
import com.amap.api.maps.AMapOptions;
import com.amap.api.maps.CameraUpdateFactory;
import com.amap.api.maps.MapView;
import com.amap.api.maps.model.LatLng;
import com.amap.api.maps.model.LatLngBounds;
import com.amap.api.maps.model.Polygon;
import com.amap.api.maps.model.PolygonOptions;

Next, create a map view object and add Add it to the layout:

MapView mapView = new MapView(context, new AMapOptions());
layout.addView(mapView);

Then, initialize the map object, and set the display position and zoom level of the map:

AMap aMap = mapView.getMap();
aMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(39.90923, 116.397428), 10));

Next, create a polygon coordinate collection and add the polygon's Each vertex coordinate:

List<LatLng> points = new ArrayList<>();
points.add(new LatLng(39.910698, 116.399406));
points.add(new LatLng(39.909819, 116.405778));
points.add(new LatLng(39.919719, 116.405814));
points.add(new LatLng(39.919657, 116.399362));

Then, create a polygon options object and set various properties of the polygon:

PolygonOptions polygonOptions = new PolygonOptions();
polygonOptions.addAll(points);
polygonOptions.strokeColor(Color.RED);
polygonOptions.fillColor(Color.argb(50, 255, 0, 0));
polygonOptions.strokeWidth(10);

Next, add the polygon to the map through the map's addPolygon method , and get the polygon object:

Polygon polygon = aMap.addPolygon(polygonOptions);

Finally, you can use the geofence function by judging whether a location is within the polygon:

LatLng location = new LatLng(39.913678, 116.403873);
boolean contains = polygon.contains(location);
System.out.println("该位置是否在多边形内：" + contains);

The above is how to use Java to develop the Amap API An introduction and sample code for geofence polygon drawing. You can easily draw a polygon through the map's addPolygon method, and you can use the contains method of the Polygon object to determine whether a location is within the polygon. The polygon drawing function of geofence can be widely used in location-related businesses, providing developers with more accurate location judgment and analysis capabilities. Hope this article helps you!

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