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/*
 * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

package javax.imageio.plugins.tiff;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;


A class representing the tags found in an Exif GPS Info IFD.

 The definitions of the data types referenced by the field definitions may be found in the TIFFTag class. 
See Also:
Since:9
/**
 * A class representing the tags found in an Exif GPS Info IFD.
 *
 * <p> The definitions of the data types referenced by the field
 * definitions may be found in the {@link TIFFTag TIFFTag} class.
 *
 * @since 9
 * @see   ExifTIFFTagSet
 */
public final class ExifGPSTagSet extends TIFFTagSet {
    private static ExifGPSTagSet theInstance = null;

    
A tag indicating the GPS tag version (type BYTE, count = 4).

See Also:
  • GPS_VERSION_2_2
/**
     * A tag indicating the GPS tag version (type BYTE, count = 4).
     *
     * @see #GPS_VERSION_2_2
     */
    public static final int TAG_GPS_VERSION_ID = 0;

    
A value to be used with the "GPSVersionID" tag to indicate GPS version 2.2. The value equals the US-ASCII encoding of the byte array {'2', '2', '0', '0'}. 
See Also:
/**
     * A value to be used with the "GPSVersionID" tag to indicate GPS version
     * 2.2.  The value equals the US-ASCII encoding of the byte array
     * {@code {'2', '2', '0', '0'}}.
     *
     * @see #TAG_GPS_VERSION_ID
     */
    public static final String GPS_VERSION_2_2 = "2200";

    
A tag indicating the North or South latitude (type ASCII, count = 2).

See Also:
/**
     * A tag indicating the North or South latitude (type ASCII, count = 2).
     *
     * @see #LATITUDE_REF_NORTH
     * @see #LATITUDE_REF_SOUTH
     */
    public static final int TAG_GPS_LATITUDE_REF = 1;

    
A tag indicating the Latitude (type RATIONAL, count = 3).

/**
     * A tag indicating the Latitude (type RATIONAL, count = 3).
     */
    public static final int TAG_GPS_LATITUDE = 2;

    
A tag indicating the East or West Longitude (type ASCII, count = 2).

See Also:
/**
     * A tag indicating the East or West Longitude (type ASCII, count = 2).
     *
     * @see #LONGITUDE_REF_EAST
     * @see #LONGITUDE_REF_WEST
     */
    public static final int TAG_GPS_LONGITUDE_REF = 3;

    
A tag indicating the Longitude (type RATIONAL, count = 3).

/**
     * A tag indicating the Longitude (type RATIONAL, count = 3).
     */
    public static final int TAG_GPS_LONGITUDE = 4;

    
A tag indicating the Altitude reference (type BYTE, count = 1);

See Also:
/**
     * A tag indicating the Altitude reference (type BYTE, count = 1);
     *
     * @see #ALTITUDE_REF_SEA_LEVEL
     * @see #ALTITUDE_REF_SEA_LEVEL_REFERENCE
     */
    public static final int TAG_GPS_ALTITUDE_REF = 5;

    
A tag indicating the Altitude (type RATIONAL, count = 1).

/**
     * A tag indicating the Altitude (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_ALTITUDE = 6;

    
A tag indicating the GPS time (atomic clock) (type RATIONAL, count = 3).

/**
     * A tag indicating the GPS time (atomic clock) (type RATIONAL, count = 3).
     */
    public static final int TAG_GPS_TIME_STAMP = 7;

    
A tag indicating the GPS satellites used for measurement (type ASCII).

/**
     * A tag indicating the GPS satellites used for measurement (type ASCII).
     */
    public static final int TAG_GPS_SATELLITES = 8;

    
A tag indicating the GPS receiver status (type ASCII, count = 2).

See Also:
/**
     * A tag indicating the GPS receiver status (type ASCII, count = 2).
     *
     * @see #STATUS_MEASUREMENT_IN_PROGRESS
     * @see #STATUS_MEASUREMENT_INTEROPERABILITY
     */
    public static final int TAG_GPS_STATUS = 9;

    
A tag indicating the GPS measurement mode (type ASCII, count = 2).

See Also:
/**
     * A tag indicating the GPS measurement mode (type ASCII, count = 2).
     *
     * @see #MEASURE_MODE_2D
     * @see #MEASURE_MODE_3D
     */
    public static final int TAG_GPS_MEASURE_MODE = 10;

    
A tag indicating the Measurement precision (type RATIONAL, count = 1).

/**
     * A tag indicating the Measurement precision (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_DOP = 11;

    
A tag indicating the Speed unit (type ASCII, count = 2).

See Also:
/**
     * A tag indicating the Speed unit (type ASCII, count = 2).
     *
     * @see #SPEED_REF_KILOMETERS_PER_HOUR
     * @see #SPEED_REF_MILES_PER_HOUR
     * @see #SPEED_REF_KNOTS
     */
    public static final int TAG_GPS_SPEED_REF = 12;

    
A tag indicating the Speed of GPS receiver (type RATIONAL, count = 1).

/**
     * A tag indicating the Speed of GPS receiver (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_SPEED = 13;

    
A tag indicating the Reference for direction of movement (type ASCII,
count = 2).

See Also:
/**
     * A tag indicating the Reference for direction of movement (type ASCII,
     * count = 2).
     *
     * @see #DIRECTION_REF_TRUE
     * @see #DIRECTION_REF_MAGNETIC
     */
    public static final int TAG_GPS_TRACK_REF = 14;

    
A tag indicating the Direction of movement (type RATIONAL, count = 1).

/**
     * A tag indicating the Direction of movement (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_TRACK = 15;

    
A tag indicating the Reference for direction of image (type ASCII,
count = 2).

See Also:
/**
     * A tag indicating the Reference for direction of image (type ASCII,
     * count = 2).
     *
     * @see #DIRECTION_REF_TRUE
     * @see #DIRECTION_REF_MAGNETIC
     */
    public static final int TAG_GPS_IMG_DIRECTION_REF = 16;

    
A tag indicating the Direction of image (type RATIONAL, count = 1).

/**
     * A tag indicating the Direction of image (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_IMG_DIRECTION = 17;

    
A tag indicating the Geodetic survey data used (type ASCII).

/**
     * A tag indicating the Geodetic survey data used (type ASCII).
     */
    public static final int TAG_GPS_MAP_DATUM = 18;

    
A tag indicating the Reference for latitude of destination (type
ASCII, count = 2).

See Also:
/**
     * A tag indicating the Reference for latitude of destination (type
     * ASCII, count = 2).
     *
     * @see #LATITUDE_REF_NORTH
     * @see #LATITUDE_REF_SOUTH
     */
    public static final int TAG_GPS_DEST_LATITUDE_REF = 19;

    
A tag indicating the Latitude of destination (type RATIONAL, count = 3).

/**
     * A tag indicating the Latitude of destination (type RATIONAL, count = 3).
     */
    public static final int TAG_GPS_DEST_LATITUDE = 20;

    
A tag indicating the Reference for longitude of destination (type
ASCII, count = 2).

See Also:
/**
     * A tag indicating the Reference for longitude of destination (type
     * ASCII, count = 2).
     *
     * @see #LONGITUDE_REF_EAST
     * @see #LONGITUDE_REF_WEST
     */
    public static final int TAG_GPS_DEST_LONGITUDE_REF = 21;

    
A tag indicating the Longitude of destination (type RATIONAL,
count = 3).

/**
     * A tag indicating the Longitude of destination (type RATIONAL,
     * count = 3).
     */
    public static final int TAG_GPS_DEST_LONGITUDE = 22;

    
A tag indicating the Reference for bearing of destination (type ASCII,
count = 2).

See Also:
/**
     * A tag indicating the Reference for bearing of destination (type ASCII,
     * count = 2).
     *
     * @see #DIRECTION_REF_TRUE
     * @see #DIRECTION_REF_MAGNETIC
     */
    public static final int TAG_GPS_DEST_BEARING_REF = 23;

    
A tag indicating the Bearing of destination (type RATIONAL, count = 1).

/**
     * A tag indicating the Bearing of destination (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_DEST_BEARING = 24;

    
A tag indicating the Reference for distance to destination (type ASCII,
count = 2).

See Also:
/**
     * A tag indicating the Reference for distance to destination (type ASCII,
     * count = 2).
     *
     * @see #DEST_DISTANCE_REF_KILOMETERS
     * @see #DEST_DISTANCE_REF_MILES
     * @see #DEST_DISTANCE_REF_KNOTS
     */
    public static final int TAG_GPS_DEST_DISTANCE_REF = 25;

    
A tag indicating the Distance to destination (type RATIONAL, count = 1).

/**
     * A tag indicating the Distance to destination (type RATIONAL, count = 1).
     */
    public static final int TAG_GPS_DEST_DISTANCE = 26;

    
A tag indicating the Name of GPS processing method (type UNDEFINED).

/**
     * A tag indicating the Name of GPS processing method (type UNDEFINED).
     */
    public static final int TAG_GPS_PROCESSING_METHOD = 27;

    
A tag indicating the Name of GPS area (type UNDEFINED).

/**
     * A tag indicating the Name of GPS area (type UNDEFINED).
     */
    public static final int TAG_GPS_AREA_INFORMATION = 28;

    
A tag indicating the GPS date (type ASCII, count 11).

/**
     * A tag indicating the GPS date (type ASCII, count 11).
     */
    public static final int TAG_GPS_DATE_STAMP = 29;

    
A tag indicating the GPS differential correction (type SHORT,
count = 1).

See Also:
/**
     * A tag indicating the GPS differential correction (type SHORT,
     * count = 1).
     *
     * @see #DIFFERENTIAL_CORRECTION_NONE
     * @see #DIFFERENTIAL_CORRECTION_APPLIED
     */
    public static final int TAG_GPS_DIFFERENTIAL = 30;

    
A value to be used with the "GPSLatitudeRef" and
"GPSDestLatitudeRef" tags.

See Also:
/**
     * A value to be used with the "GPSLatitudeRef" and
     * "GPSDestLatitudeRef" tags.
     *
     * @see #TAG_GPS_LATITUDE_REF
     * @see #TAG_GPS_DEST_LATITUDE_REF
     */
    public static final String LATITUDE_REF_NORTH = "N";

    
A value to be used with the "GPSLatitudeRef" and
"GPSDestLatitudeRef" tags.

See Also:
/**
     * A value to be used with the "GPSLatitudeRef" and
     * "GPSDestLatitudeRef" tags.
     *
     * @see #TAG_GPS_LATITUDE_REF
     * @see #TAG_GPS_DEST_LATITUDE_REF
     */
    public static final String LATITUDE_REF_SOUTH = "S";

    
A value to be used with the "GPSLongitudeRef" and
"GPSDestLongitudeRef" tags.

See Also:
/**
     * A value to be used with the "GPSLongitudeRef" and
     * "GPSDestLongitudeRef" tags.
     *
     * @see #TAG_GPS_LONGITUDE_REF
     * @see #TAG_GPS_DEST_LONGITUDE_REF
     */
    public static final String LONGITUDE_REF_EAST = "E";

    
A value to be used with the "GPSLongitudeRef" and
"GPSDestLongitudeRef" tags.

See Also:
/**
     * A value to be used with the "GPSLongitudeRef" and
     * "GPSDestLongitudeRef" tags.
     *
     * @see #TAG_GPS_LONGITUDE_REF
     * @see #TAG_GPS_DEST_LONGITUDE_REF
     */
    public static final String LONGITUDE_REF_WEST = "W";

    
A value to be used with the "GPSAltitudeRef" tag.

See Also:
  • TAG_GPS_ALTITUDE_REF
/**
     * A value to be used with the "GPSAltitudeRef" tag.
     *
     * @see #TAG_GPS_ALTITUDE_REF
     */
    public static final int ALTITUDE_REF_SEA_LEVEL = 0;

    
A value to be used with the "GPSAltitudeRef" tag.

See Also:
  • TAG_GPS_ALTITUDE_REF
/**
     * A value to be used with the "GPSAltitudeRef" tag.
     *
     * @see #TAG_GPS_ALTITUDE_REF
     */
    public static final int ALTITUDE_REF_SEA_LEVEL_REFERENCE = 1;

    
A value to be used with the "GPSStatus" tag.

See Also:
  • TAG_GPS_STATUS
/**
     * A value to be used with the "GPSStatus" tag.
     *
     * @see #TAG_GPS_STATUS
     */
    public static final String STATUS_MEASUREMENT_IN_PROGRESS = "A";

    
A value to be used with the "GPSStatus" tag.

See Also:
  • TAG_GPS_STATUS
/**
     * A value to be used with the "GPSStatus" tag.
     *
     * @see #TAG_GPS_STATUS
     */
    public static final String STATUS_MEASUREMENT_INTEROPERABILITY = "V";

    
A value to be used with the "GPSMeasureMode" tag.

See Also:
  • TAG_GPS_MEASURE_MODE
/**
     * A value to be used with the "GPSMeasureMode" tag.
     *
     * @see #TAG_GPS_MEASURE_MODE
     */
    public static final String MEASURE_MODE_2D = "2";

    
A value to be used with the "GPSMeasureMode" tag.

See Also:
  • TAG_GPS_MEASURE_MODE
/**
     * A value to be used with the "GPSMeasureMode" tag.
     *
     * @see #TAG_GPS_MEASURE_MODE
     */
    public static final String MEASURE_MODE_3D = "3";

    
A value to be used with the "GPSSpeedRef" tag.

See Also:
  • TAG_GPS_SPEED_REF
/**
     * A value to be used with the "GPSSpeedRef" tag.
     *
     * @see #TAG_GPS_SPEED_REF
     */
    public static final String SPEED_REF_KILOMETERS_PER_HOUR = "K";

    
A value to be used with the "GPSSpeedRef" tag.

See Also:
  • TAG_GPS_SPEED_REF
/**
     * A value to be used with the "GPSSpeedRef" tag.
     *
     * @see #TAG_GPS_SPEED_REF
     */
    public static final String SPEED_REF_MILES_PER_HOUR = "M";

    
A value to be used with the "GPSSpeedRef" tag.

See Also:
  • TAG_GPS_SPEED_REF
/**
     * A value to be used with the "GPSSpeedRef" tag.
     *
     * @see #TAG_GPS_SPEED_REF
     */
    public static final String SPEED_REF_KNOTS = "N";

    
A value to be used with the "GPSTrackRef", "GPSImgDirectionRef",
and "GPSDestBearingRef" tags.

See Also:
/**
     * A value to be used with the "GPSTrackRef", "GPSImgDirectionRef",
     * and "GPSDestBearingRef" tags.
     *
     * @see #TAG_GPS_TRACK_REF
     * @see #TAG_GPS_IMG_DIRECTION_REF
     * @see #TAG_GPS_DEST_BEARING_REF
     */
    public static final String DIRECTION_REF_TRUE = "T";

    
A value to be used with the "GPSTrackRef", "GPSImgDirectionRef",
and "GPSDestBearingRef" tags.

See Also:
/**
     * A value to be used with the "GPSTrackRef", "GPSImgDirectionRef",
     * and "GPSDestBearingRef" tags.
     *
     * @see #TAG_GPS_TRACK_REF
     * @see #TAG_GPS_IMG_DIRECTION_REF
     * @see #TAG_GPS_DEST_BEARING_REF
     */
    public static final String DIRECTION_REF_MAGNETIC = "M";

    
A value to be used with the "GPSDestDistanceRef" tag.

See Also:
  • TAG_GPS_DEST_DISTANCE_REF
/**
     * A value to be used with the "GPSDestDistanceRef" tag.
     *
     * @see #TAG_GPS_DEST_DISTANCE_REF
     */
    public static final String DEST_DISTANCE_REF_KILOMETERS = "K";

    
A value to be used with the "GPSDestDistanceRef" tag.

See Also:
  • TAG_GPS_DEST_DISTANCE_REF
/**
     * A value to be used with the "GPSDestDistanceRef" tag.
     *
     * @see #TAG_GPS_DEST_DISTANCE_REF
     */
    public static final String DEST_DISTANCE_REF_MILES = "M";

    
A value to be used with the "GPSDestDistanceRef" tag.

See Also:
  • TAG_GPS_DEST_DISTANCE_REF
/**
     * A value to be used with the "GPSDestDistanceRef" tag.
     *
     * @see #TAG_GPS_DEST_DISTANCE_REF
     */
    public static final String DEST_DISTANCE_REF_KNOTS = "N";

    
A value to be used with the "GPSDifferential" tag.

See Also:
  • TAG_GPS_DIFFERENTIAL
/**
     * A value to be used with the "GPSDifferential" tag.
     *
     * @see #TAG_GPS_DIFFERENTIAL
     */
    public static final int DIFFERENTIAL_CORRECTION_NONE = 0;

    
A value to be used with the "GPSDifferential" tag.

See Also:
  • TAG_GPS_DIFFERENTIAL
/**
     * A value to be used with the "GPSDifferential" tag.
     *
     * @see #TAG_GPS_DIFFERENTIAL
     */
    public static final int DIFFERENTIAL_CORRECTION_APPLIED = 1;

    static class GPSVersionID extends TIFFTag {
        public GPSVersionID() {
            super("GPSVersionID",
                  TAG_GPS_VERSION_ID,
                  1 << TIFFTag.TIFF_BYTE);
        }
    }

    static class GPSLatitudeRef extends TIFFTag {
        public GPSLatitudeRef() {
            super("GPSLatitudeRef",
                  TAG_GPS_LATITUDE_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSLatitude extends TIFFTag {
        public GPSLatitude() {
            super("GPSLatitude",
                  TAG_GPS_LATITUDE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSLongitudeRef extends TIFFTag {
        public GPSLongitudeRef() {
            super("GPSLongitudeRef",
                  TAG_GPS_LONGITUDE_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSLongitude extends TIFFTag {
        public GPSLongitude() {
            super("GPSLongitude",
                  TAG_GPS_LONGITUDE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSAltitudeRef extends TIFFTag {
        public GPSAltitudeRef() {
            super("GPSAltitudeRef",
                  TAG_GPS_ALTITUDE_REF,
                  1 << TIFFTag.TIFF_BYTE);

            addValueName(ALTITUDE_REF_SEA_LEVEL, "Sea level");
            addValueName(ALTITUDE_REF_SEA_LEVEL_REFERENCE,
                         "Sea level reference (negative value)");
        }
    }

    static class GPSAltitude extends TIFFTag {
        public GPSAltitude() {
            super("GPSAltitude",
                  TAG_GPS_ALTITUDE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSTimeStamp extends TIFFTag {
        public GPSTimeStamp() {
            super("GPSTimeStamp",
                  TAG_GPS_TIME_STAMP,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSSatellites extends TIFFTag {
        public GPSSatellites() {
            super("GPSSatellites",
                  TAG_GPS_SATELLITES,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSStatus extends TIFFTag {
        public GPSStatus() {
            super("GPSStatus",
                  TAG_GPS_STATUS,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSMeasureMode extends TIFFTag {
        public GPSMeasureMode() {
            super("GPSMeasureMode",
                  TAG_GPS_MEASURE_MODE,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDOP extends TIFFTag {
        public GPSDOP() {
            super("GPSDOP",
                  TAG_GPS_DOP,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSSpeedRef extends TIFFTag {
        public GPSSpeedRef() {
            super("GPSSpeedRef",
                  TAG_GPS_SPEED_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSSpeed extends TIFFTag {
        public GPSSpeed() {
            super("GPSSpeed",
                  TAG_GPS_SPEED,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSTrackRef extends TIFFTag {
        public GPSTrackRef() {
            super("GPSTrackRef",
                  TAG_GPS_TRACK_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSTrack extends TIFFTag {
        public GPSTrack() {
            super("GPSTrack",
                  TAG_GPS_TRACK,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSImgDirectionRef extends TIFFTag {
        public GPSImgDirectionRef() {
            super("GPSImgDirectionRef",
                  TAG_GPS_IMG_DIRECTION_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSImgDirection extends TIFFTag {
        public GPSImgDirection() {
            super("GPSImgDirection",
                  TAG_GPS_IMG_DIRECTION,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSMapDatum extends TIFFTag {
        public GPSMapDatum() {
            super("GPSMapDatum",
                  TAG_GPS_MAP_DATUM,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDestLatitudeRef extends TIFFTag {
        public GPSDestLatitudeRef() {
            super("GPSDestLatitudeRef",
                  TAG_GPS_DEST_LATITUDE_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDestLatitude extends TIFFTag {
        public GPSDestLatitude() {
            super("GPSDestLatitude",
                  TAG_GPS_DEST_LATITUDE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSDestLongitudeRef extends TIFFTag {
        public GPSDestLongitudeRef() {
            super("GPSDestLongitudeRef",
                  TAG_GPS_DEST_LONGITUDE_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDestLongitude extends TIFFTag {
        public GPSDestLongitude() {
            super("GPSDestLongitude",
                  TAG_GPS_DEST_LONGITUDE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSDestBearingRef extends TIFFTag {
        public GPSDestBearingRef() {
            super("GPSDestBearingRef",
                  TAG_GPS_DEST_BEARING_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDestBearing extends TIFFTag {
        public GPSDestBearing() {
            super("GPSDestBearing",
                  TAG_GPS_DEST_BEARING,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSDestDistanceRef extends TIFFTag {
        public GPSDestDistanceRef() {
            super("GPSDestDistanceRef",
                  TAG_GPS_DEST_DISTANCE_REF,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDestDistance extends TIFFTag {
        public GPSDestDistance() {
            super("GPSDestDistance",
                  TAG_GPS_DEST_DISTANCE,
                  1 << TIFFTag.TIFF_RATIONAL);
        }
    }

    static class GPSProcessingMethod extends TIFFTag {
        public GPSProcessingMethod() {
            super("GPSProcessingMethod",
                  TAG_GPS_PROCESSING_METHOD,
                  1 << TIFFTag.TIFF_UNDEFINED);
        }
    }

    static class GPSAreaInformation extends TIFFTag {
        public GPSAreaInformation() {
            super("GPSAreaInformation",
                  TAG_GPS_AREA_INFORMATION,
                  1 << TIFFTag.TIFF_UNDEFINED);
        }
    }

    static class GPSDateStamp extends TIFFTag {
        public GPSDateStamp() {
            super("GPSDateStamp",
                  TAG_GPS_DATE_STAMP,
                  1 << TIFFTag.TIFF_ASCII);
        }
    }

    static class GPSDifferential extends TIFFTag {
        public GPSDifferential() {
            super("GPSDifferential",
                  TAG_GPS_DIFFERENTIAL,
                  1 << TIFFTag.TIFF_SHORT);
            addValueName(DIFFERENTIAL_CORRECTION_NONE,
                         "Measurement without differential correction");
            addValueName(DIFFERENTIAL_CORRECTION_APPLIED,
                         "Differential correction applied");

        }
    }

    private static List<TIFFTag> initTags() {
        ArrayList<TIFFTag> tags = new ArrayList<TIFFTag>(31);

        tags.add(new GPSVersionID());
        tags.add(new GPSLatitudeRef());
        tags.add(new GPSLatitude());
        tags.add(new GPSLongitudeRef());
        tags.add(new GPSLongitude());
        tags.add(new GPSAltitudeRef());
        tags.add(new GPSAltitude());
        tags.add(new GPSTimeStamp());
        tags.add(new GPSSatellites());
        tags.add(new GPSStatus());
        tags.add(new GPSMeasureMode());
        tags.add(new GPSDOP());
        tags.add(new GPSSpeedRef());
        tags.add(new GPSSpeed());
        tags.add(new GPSTrackRef());
        tags.add(new GPSTrack());
        tags.add(new GPSImgDirectionRef());
        tags.add(new GPSImgDirection());
        tags.add(new GPSMapDatum());
        tags.add(new GPSDestLatitudeRef());
        tags.add(new GPSDestLatitude());
        tags.add(new GPSDestLongitudeRef());
        tags.add(new GPSDestLongitude());
        tags.add(new GPSDestBearingRef());
        tags.add(new GPSDestBearing());
        tags.add(new GPSDestDistanceRef());
        tags.add(new GPSDestDistance());
        tags.add(new GPSProcessingMethod());
        tags.add(new GPSAreaInformation());
        tags.add(new GPSDateStamp());
        tags.add(new GPSDifferential());
        return tags;
    }

    private ExifGPSTagSet() {
        super(initTags());
    }

    
Returns a shared instance of an ExifGPSTagSet. 
Returns:an ExifGPSTagSet instance.
/**
     * Returns a shared instance of an {@code ExifGPSTagSet}.
     *
     * @return an {@code ExifGPSTagSet} instance.
     */
    public synchronized static ExifGPSTagSet getInstance() {
        if (theInstance == null) {
            theInstance = new ExifGPSTagSet();
        }
        return theInstance;
    }
}