Google Map Tile Provider (GeoServer And WMS)

Question

I try to get Tile Information(I, J , BBOX) on selected Latitude and Longitude with zooming level in Google Map.

I used this formula to get I, J , BBOX Formula Source

private void getXYFromLatLon(double lat, double lon, final int zoom) {
    int tileSize = 256;
    // double initialResolution = 2 * Math.PI * 6378137 / tileSize;
    double initialResolution = 156543.03392804062;
    double originShift = 20037508.342789244;
    // LatLong to Meter
    double mx = lon * originShift / 180.0;
    double my = Math.log(Math.tan((90 + lat) * Math.PI / 360.0))
            / (Math.PI / 180.0);
    my = my * originShift / 180.0;
    // Meter to Pixels
    double res = initialResolution / (2 * zoom);
    double px = (mx + originShift) / res;
    double py = (my + originShift) / res;

    getBoundingBox(Double.valueOf(px).intValue(), Double.valueOf(py)
            .intValue(), zoom);
    // Pixel to tiles
    final int tx = (int) Math.ceil(px / ((tileSize)) - 1);
    final int ty = (int) Math.ceil(py / ((tileSize)) - 1);

    getTileBound(tx, ty, zoom, tileSize);

    Toast.makeText(getApplicationContext(), "X: " + tx + ",Y: " + ty,
            Toast.LENGTH_SHORT).show();

}private void getTileBound(int tx, int ty, int zoom, int tileSize) {
    double[] min = pixelToMeter(tx * tileSize, ty * tileSize, zoom);
    double[] max = pixelToMeter((tx + 1) * tileSize, (ty + 1) * tileSize,
            zoom);

    builder.append("\nMIN-X:" + min[0]).append("\nMIN-Y:" + min[1])
            .append("\nMAX-X:" + max[0]).append("\nMAX-Y:" + max[1])
            .append("\nI:" + (tx)).append("\nJ:" + (ty));
    ((TextView) findViewById(R.id.textView1)).setText(builder.toString());
    /*
     * Toast.makeText(getApplicationContext(), "X: " + min.toString() +
     * ",Y: " + max.toString(), Toast.LENGTH_SHORT).show();
     */
}public String getTileNumber(final double lat, final double lon,
        final int zoom) {
    int xtile = (int) Math.floor((lon + 180) / 360 * (1 << zoom));
    int ytile = (int) Math
            .floor((1 - Math.log(Math.tan(Math.toRadians(lat)) + 1
                    / Math.cos(Math.toRadians(lat)))
                    / Math.PI)
                    / 2 * (1 << zoom));
    if (xtile < 0)
        xtile = 0;
    if (xtile >= (1 << zoom))
        xtile = ((1 << zoom) - 1);
    if (ytile < 0)
        ytile = 0;
    if (ytile >= (1 << zoom))
        ytile = ((1 << zoom) - 1);
    System.out.println("xtile" + xtile);

    // Toast.makeText(getApplicationContext(),
    // xtile + "YY" + ytile + "Zoom" + (1 << zoom), Toast.LENGTH_LONG)
    // .show();
    return ("" + zoom + "/" + xtile + "/" + ytile);

}private double[] pixelToMeter(int x, int y, int zoom) {
    int tileSize = 256;
    double initialResolution = 2 * Math.PI * 6378137 / tileSize;
    double originShift = 2 * Math.PI * 6378137 / 2;
    double res = initialResolution / (2 * zoom);
    double mx = x * res - originShift;
    double my = y * res - originShift;

    return new double[] { mx, my };

}

The problem based on zooming level i'm not able to find the exact value .. Based on correct value i to have call the WMS webservices

Thanks in advance...

http://192.168.1.102:1005/geoserver/estater/wms?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetFeatureInfo&FORMAT=image%2Fpng&TRANSPARENT=true&QUERY_LAYERS=buildings&LAYERS=kwt_buildings&INFO_FORMAT=application%2Fjson&propertyName=grid_id%2Cbuild_id&I=90&J=161&WIDTH=256&HEIGHT=256&CRS=EPSG%3A3857&STYLES=&BBOX=5342031.032794397%2C3420709.8898182083%2C5343254.02524696%2C3421932.882270771

N Dorigatti N Dorigatti · Accepted Answer · 2015-09-04T07:20:39

I did not look at your code, but I have mine working since years, so here it is the WMS tile provider class:

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);
}

@SuppressWarnings("deprecation")
protected String getCql() {
    try {
        return URLEncoder.encode(cqlString, Charset.defaultCharset().name());
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        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;
}
}

And here is something on how i use it:

public static WMSTileProvider getWMSTileProviderByName(String layerName) {
        final String OSGEO_WMS = "http://yourserver/geoserver/gwc/service/wms/?"
                + "LAYERS=" + layerName
                + "&FORMAT=image/png8&"
                + "PROJECTION=EPSG:3857&"
                + "TILEORIGIN=lon=-20037508.34,lat=-20037508.34&"
                + "TILESIZE=w=256,h=256"
                + "&MAXEXTENT=-20037508.34,-20037508.34,20037508.34,20037508.34&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG:3857"
                + "&BBOX=%f,%f,%f,%f&WIDTH=256&HEIGHT=256";

        return new WMSTileProvider(256, 256) {

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

Can't give you more code, but I hope can help you

EDIT: Given the comment, now i see what you need. Here it is some code (old but working) on which you have to work a bit, it was a sort of hack:

    private static final double[] TILES_ORIGIN = {-20037508.34789244, 20037508.34789244};//TODO Duplicate from WMS PROVIDER, put as utils
    // Size of square world map in meters, using WebMerc projection.
    private static final double MAP_SIZE = 20037508.34789244 * 2;//TODO Duplicate from WMS PROVIDER, put as utils
    private static final double ORIGIN_SHIFT = Math.PI * 6378137d;

/**
     * Transform the y map meter in y cordinate
     *
     * @param latitude the latitude of map
     * @return meters of y cordinate
     */
    private double inMetersYCoordinate(double latitude) {
        if (latitude < 0) {
            return -inMetersYCoordinate(-latitude);
        }
        return (Math.log(Math.tan((90d + latitude) * Math.PI / 360d)) / (Math.PI / 180d)) * ORIGIN_SHIFT / 180d;
    }

    /**
     * Transform the x map meter in x cordinate
     *
     * @param longitude the longitude of map
     * @return meters of x cordinate
     */
    private double inMetersXCoordinate(double longitude) {
        return longitude * ORIGIN_SHIFT / 180.0;
    }

/**
     * Get the Tile from x and y cordinates
     *
     * @param pointX    x of the map
     * @param pointY    y of the map
     * @param zoomLevel zoom of Tile
     * @return the relative TileDataInfo
     */
private TileDataInfo getTileByCoordinate(double pointX, double pointY, int zoomLevel) {
    final double tileDim = MAP_SIZE / Math.pow(2d, zoomLevel);

    final int tileX = (int) ((pointX - TILES_ORIGIN[0]) / tileDim);
    final int tileY = (int) ((TILES_ORIGIN[1] - pointY) / tileDim);

    return new TileDataInfo(tileX, tileY, zoomLevel);
}

private static class TileDataInfo {
    int tileX;
    int tileY;
    int tileZoom;

    public TileDataInfo(int tileX, int tileY, int tileZoom) {
        this.tileX = tileX;
        this.tileY = tileY;
        this.tileZoom = tileZoom;
    }

}

In order to get the code right, you have to convert latitude in meters using the "inMetersYCoordinate", the longitude using "inMetersXCoordinate" and then use "getTileByCoordinate" to calculate the tile x,y,z (i,j,zoom for you)

Google Map Tile Provider (GeoServer And WMS)

1 Answers