WellKnownZoomContextFinder.java

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2016 Open Source Geospatial Foundation (OSGeo)
 *    (C) 2014-2016 Boundless Spatial
 *    
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.ysld.parse;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

import javax.annotation.Nullable;

/**
 * A collection of commonly used ZoomContexts
 * 
 * @author Kevin Smith, Boundless
 *
 */
public class WellKnownZoomContextFinder implements ZoomContextFinder {

    static private WellKnownZoomContextFinder INSTANCE = new WellKnownZoomContextFinder();

    public static WellKnownZoomContextFinder getInstance() {
        return INSTANCE;
    }

    private WellKnownZoomContextFinder() {
        contexts = new HashMap<>();
        canonicalNames = new TreeSet<>();

        // Google Spherical Mercator at 96 DPI
        ZoomContext googleMercatorExtended = new RatioZoomContext(559_082_263.9508929, 2);
        contexts.put("WebMercator".toUpperCase(), googleMercatorExtended);
        contexts.put("SphericalMercator".toUpperCase(), googleMercatorExtended);
        contexts.put("GoogleMercator".toUpperCase(), googleMercatorExtended);
        contexts.put("EPSG:3587".toUpperCase(), googleMercatorExtended);
        contexts.put("EPSG:900913".toUpperCase(), googleMercatorExtended); // The name used by GWC
        contexts.put("EPSG:3857".toUpperCase(), googleMercatorExtended);
        contexts.put("EPSG:3785".toUpperCase(), googleMercatorExtended);
        contexts.put("OSGEO:41001".toUpperCase(), googleMercatorExtended);
        contexts.put("DEFAULT".toUpperCase(), googleMercatorExtended);
        canonicalNames.add("EPSG:3857");

        // WGS84 Plate Carrée starting with one 256x256 tile at 96 DPI
        // Do NOT use the name EPSG:4326 as GWC defines a gridset named that. with different levels.
        ZoomContext plateCarree = new RatioZoomContext(559_082_263.9508929, 2);
        contexts.put("PlateCarree".toUpperCase(), plateCarree);
        contexts.put("PlateCarrée".toUpperCase(), plateCarree);
        contexts.put("WGS84".toUpperCase(), plateCarree);
        contexts.put("CRS84".toUpperCase(), plateCarree);
        contexts.put("GoogleCRS84Quad".toUpperCase(), plateCarree); // The Name used by GWC
        canonicalNames.add("WGS84");

        // Note the above two contexts have identical zoom levels but are conceptually distinct due
        // to the difference in CRS.
        
        ZoomContext niceScales = new ListZoomContext(Arrays.asList(
                5_000_000_000d,
                2_000_000_000d,
                1_000_000_000d,
                  500_000_000d, // 0
                  200_000_000d,
                  100_000_000d,
                   50_000_000d,
                   20_000_000d,
                   10_000_000d,
                    5_000_000d,
                    2_000_000d,
                    1_000_000d,
                      500_000d,
                      200_000d,
                      100_000d,
                       50_000d,
                       20_000d,
                       10_000d,
                        5_000d,
                        2_000d,
                        1_000d,
                          500d,
                          200d,
                          100d,
                           50d,
                           20d,
                           10d,
                            5d,
                            2d,
                            1d
                ), -3);
        contexts.put("NiceScales".toUpperCase(), niceScales);
        canonicalNames.add("NiceScales");
    }

    final Set<String> canonicalNames;

    final Map<String, ZoomContext> contexts;

    @Override
    public @Nullable ZoomContext get(String name) {
        return contexts.get(name.toUpperCase());
    }

    @Override
    public Set<String> getNames() {
        return contexts.keySet();
    }

    @Override
    public Set<String> getCanonicalNames() {
        return Collections.unmodifiableSet(canonicalNames);
    }

}