android - WMS On Android 磁贴加载问题

Question

我正在使用 Google Maps v2 显示来自 wms 的图 block 。我提到了this地点。加载图 block 时出现问题，它们加载了多次我不知道？任何人都可以帮助我吗？

这是我的代码

package com.example.testgooglemaps;

import android.app.Activity;
import android.os.Bundle;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.TileOverlayOptions;
import com.google.android.gms.maps.model.TileProvider;

public class Lanch extends Activity {

    // Google Map
    private GoogleMap googleMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_lanch);

        try {
            // Loading map
            initilizeMap();

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    /**
     * function to load map. If map is not created it will create it for you
     * */
    private void initilizeMap() {
        if (googleMap == null) {
            googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();

            // check if map is created successfully or not
            if (googleMap != null) {
                setUpMap();
            }
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        initilizeMap();
    }

    private void setUpMap() {
        TileProvider wmsTileProvider = TileProviderFactory.getOsgeoWmsTileProvider();
        googleMap.addTileOverlay(new TileOverlayOptions().tileProvider(wmsTileProvider));

        // to satellite so we can see the WMS overlay.
        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    }

}

TileProvider 类...

package com.example.testgooglemaps;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Locale;

import android.util.Log;

public class TileProviderFactory {

    public static WMSTileProvider getOsgeoWmsTileProvider() {

        final String OSGEO_WMS =  "http://localhost/geoserver/magnamaps/wms?service=WMS&version=1.1.0&request=GetMap&layers=magnamaps:bang_apartments&styles=&bbox=%f,%f,%f,%f&width=256&height=256&crs=EPSG:4326&format=image/png&transparent=true";

        WMSTileProvider tileProvider = new WMSTileProvider(256, 256) {

            @Override
            public synchronized URL getTileUrl(int x, int y, int zoom) {
                double[] bbox = getBoundingBox(x, y, zoom);
                String s = String.format(Locale.US, OSGEO_WMS, bbox[MINX], bbox[MINY], bbox[MAXX], bbox[MAXY]);
                Log.d("WMSDEMO", s);
                URL url = null;
                try {
                    url = new URL(s);
                } catch (MalformedURLException e) {
                    throw new AssertionError(e);
                }
                return url;
            }
        };
        return tileProvider;
    }
}

WMSTileProvider 类...

package com.example.testgooglemaps;

import java.net.URLEncoder;

import com.google.android.gms.maps.model.UrlTileProvider;

public abstract class WMSTileProvider extends UrlTileProvider {

    // Web Mercator n/w corner of the map.
    private static final double[] TILE_ORIGIN = { -20037508.34789244, 20037508.34789244 };
    // array indexes for that data
    private static final int ORIG_X = 0;
    private static final int ORIG_Y = 1; // "

    // Size of square world map in meters, using WebMerc projection.
    private static final double MAP_SIZE = 20037508.34789244 * 2;

    // array indexes for array to hold bounding boxes.
    protected static final int MINX = 0;
    protected static final int MAXX = 1;
    protected static final int MINY = 2;
    protected static final int MAXY = 3;

    // cql filters
    private String cqlString = "";

    // Construct with tile size in pixels, normally 256, see parent class.
    public WMSTileProvider(int x, int y) {
        super(x, y);
    }

    protected String getCql() {
        return URLEncoder.encode(cqlString);
    }

    public void setCql(String c) {
        cqlString = c;
    }

    // Return a web Mercator bounding box given tile x/y indexes and a zoom
    // level.
    protected double[] getBoundingBox(int x, int y, int zoom) {
        double tileSize = MAP_SIZE / Math.pow(2, zoom);
        double minx = TILE_ORIGIN[ORIG_X] + x * tileSize;
        double maxx = TILE_ORIGIN[ORIG_X] + (x + 1) * tileSize;
        double miny = TILE_ORIGIN[ORIG_Y] - (y + 1) * tileSize;
        double maxy = TILE_ORIGIN[ORIG_Y] - y * tileSize;

        double[] bbox = new double[4];
        bbox[MINX] = minx;
        bbox[MINY] = miny;
        bbox[MAXX] = maxx;
        bbox[MAXY] = maxy;

        return bbox;
    }

}

编辑:在初始化 map 本身时，缩放级别设置为 3，在此方法中 getTileUrl(int x, int y, int zoom)

Answer 1

在 WMSTileProvider.getBoundingBox 中，您正在计算以 Web 墨卡托投影为单位的边界框，即米。在您的 OSGEO_WMS URL 字符串中，您指定 bbox 单位为 EPSG:4326(度)。因此，每个图 block 的查询很可能是不正确的。

参见 WMS reference对于 bbox 和 srs:

bbox: Bounding box for map extent. Value is minx,miny,maxx,maxy in units of the SRS.

尝试用 EPSG:3857 (WebMercator) 替换您的 srs 值