tim/prune/data/Coordinate.java

   1 package tim.prune.data;
   2
   3 /**
   4  * Class to represent a lat/long coordinate
   5  * and provide conversion functions
   6  */
   7 public abstract class Coordinate
   8 {
   9         public static final int NORTH = 0;
  10         public static final int EAST = 1;
  11         public static final int SOUTH = 2;
  12         public static final int WEST = 3;
  13         public static final char[] PRINTABLE_CARDINALS = {'N', 'E', 'S', 'W'};
  14         public static final int FORMAT_DEG_MIN_SEC = 10;
  15         public static final int FORMAT_DEG_MIN = 11;
  16         public static final int FORMAT_DEG = 12;
  17         public static final int FORMAT_DEG_WITHOUT_CARDINAL = 13;
  18         public static final int FORMAT_NONE = 19;
  19
  20         // Instance variables
  21         private boolean _valid = false;
  22         protected int _cardinal = NORTH;
  23         private int _degrees = 0;
  24         private int _minutes = 0;
  25         private int _seconds = 0;
  26         private int _fracs = 0;
  27         private String _originalString = null;
  28         private int _originalFormat = FORMAT_NONE;
  29         private double _asDouble = 0.0;
  30
  31
  32         /**
  33          * Constructor given String
  34          * @param inString string to parse
  35          */
  36         public Coordinate(String inString)
  37         {
  38                 _originalString = inString;
  39                 int strLen = 0;
  40                 if (inString != null)
  41                 {
  42                         inString = inString.trim();
  43                         strLen = inString.length();
  44                 }
  45                 if (strLen > 1)
  46                 {
  47                         // Check for leading character NSEW
  48                         _cardinal = getCardinal(inString.charAt(0));
  49                         // count numeric fields - 1=d, 2=dm, 3=dm.m/dms, 4=dms.s
  50                         int numFields = 0;
  51                         boolean inNumeric = false;
  52                         char currChar;
  53                         long[] fields = new long[4];
  54                         long[] denoms = new long[4];
  55                         try
  56                         {
  57                                 for (int i=0; i<strLen; i++)
  58                                 {
  59                                         currChar = inString.charAt(i);
  60                                         if (currChar >= '0' && currChar <= '9')
  61                                         {
  62                                                 if (!inNumeric)
  63                                                 {
  64                                                         inNumeric = true;
  65                                                         numFields++;
  66                                                         denoms[numFields-1] = 1;
  67                                                 }
  68                                                 fields[numFields-1] = fields[numFields-1] * 10 + (currChar - '0');
  69                                                 denoms[numFields-1] *= 10;
  70                                         }
  71                                         else
  72                                         {
  73                                                 inNumeric = false;
  74                                         }
  75                                 }
  76                                 _valid = (numFields > 0);
  77                         }
  78                         catch (ArrayIndexOutOfBoundsException obe)
  79                         {
  80                                 // more than four fields found - unable to parse
  81                                 _valid = false;
  82                         }
  83                         // parse fields according to number found
  84                         _degrees = (int) fields[0];
  85                         _originalFormat = FORMAT_DEG;
  86                         if (numFields == 2)
  87                         {
  88                                 // String is just decimal degrees
  89                                 double numMins = fields[1] * 60.0 / denoms[1];
  90                                 _minutes = (int) numMins;
  91                                 double numSecs = (numMins - _minutes) * 60.0;
  92                                 _seconds = (int) numSecs;
  93                                 _fracs = (int) ((numSecs - _seconds) * 10);
  94                         }
  95                         else if (numFields == 3)
  96                         {
  97                                 // String is degrees-minutes.fractions
  98                                 _originalFormat = FORMAT_DEG_MIN;
  99                                 _minutes = (int) fields[1];
 100                                 double numSecs = fields[2] * 60.0 / denoms[2];
 101                                 _seconds = (int) numSecs;
 102                                 _fracs = (int) ((numSecs - _seconds) * 10);
 103                         }
 104                         else if (numFields == 4)
 105                         {
 106                                 _originalFormat = FORMAT_DEG_MIN_SEC;
 107                                 // String is degrees-minutes-seconds.fractions
 108                                 _minutes = (int) fields[1];
 109                                 _seconds = (int) fields[2];
 110                                 _fracs = (int) fields[3];
 111                         }
 112                         _asDouble = 1.0 * _degrees + (_minutes / 60.0) + (_seconds / 3600.0) + (_fracs / 36000.0);
 113                         if (_cardinal == WEST || _cardinal == SOUTH || inString.charAt(0) == '-')
 114                                 _asDouble = -_asDouble;
 115                 }
 116                 else _valid = false;
 117         }
 118
 119
 120         /**
 121          * Get the cardinal from the given character
 122          * @param inChar character from file
 123          */
 124         protected abstract int getCardinal(char inChar);
 125
 126
 127         /**
 128          * Constructor
 129          * @param inValue value of coordinate
 130          * @param inFormat format to use
 131          */
 132         protected Coordinate(double inValue, int inFormat)
 133         {
 134                 _asDouble = inValue;
 135                 // Calculate degrees, minutes, seconds
 136                 _degrees = (int) inValue;
 137                 double numMins = (Math.abs(_asDouble)-Math.abs(_degrees)) * 60.0;
 138                 _minutes = (int) numMins;
 139                 double numSecs = (numMins - _minutes) * 60.0;
 140                 _seconds = (int) numSecs;
 141                 _fracs = (int) ((numSecs - _seconds) * 10);
 142                 // Make a string to display on screen
 143                 _originalFormat = FORMAT_NONE;
 144                 if (inFormat == FORMAT_NONE) inFormat = FORMAT_DEG_WITHOUT_CARDINAL;
 145                 _originalString = output(inFormat);
 146                 _originalFormat = inFormat;
 147         }
 148
 149
 150         /**
 151          * @return coordinate as a double
 152          */
 153         public double getDouble()
 154         {
 155                 return _asDouble;
 156         }
 157
 158         /**
 159          * @return true if Coordinate is valid
 160          */
 161         public boolean isValid()
 162         {
 163                 return _valid;
 164         }
 165
 166         /**
 167          * Compares two Coordinates for equality
 168          * @param inOther other Coordinate object with which to compare
 169          * @return true if the two objects are equal
 170          */
 171         public boolean equals(Coordinate inOther)
 172         {
 173                 return (inOther != null && _cardinal == inOther._cardinal
 174                         && _degrees == inOther._degrees
 175                         && _minutes == inOther._minutes
 176                         && _seconds == inOther._seconds
 177                         && _fracs == inOther._fracs);
 178         }
 179
 180
 181         /**
 182          * Output the Coordinate in the given format
 183          * @param inOriginalString the original String to use as default
 184          * @param inFormat format to use, eg FORMAT_DEG_MIN_SEC
 185          * @return String for output
 186          */
 187         public String output(int inFormat)
 188         {
 189                 String answer = _originalString;
 190                 if (inFormat != FORMAT_NONE && inFormat != _originalFormat)
 191                 {
 192                         // TODO: allow specification of precision for output of d-m and d
 193                         // format as specified
 194                         switch (inFormat)
 195                         {
 196                                 case FORMAT_DEG_MIN_SEC: {
 197                                         StringBuffer buffer = new StringBuffer();
 198                                         buffer.append(PRINTABLE_CARDINALS[_cardinal])
 199                                                 .append(threeDigitString(_degrees)).append('°')
 200                                                 .append(twoDigitString(_minutes)).append('\'')
 201                                                 .append(twoDigitString(_seconds)).append('.')
 202                                                 .append(_fracs);
 203                                         answer = buffer.toString(); break;
 204                                 }
 205                                 case FORMAT_DEG_MIN: answer = "" + PRINTABLE_CARDINALS[_cardinal] + threeDigitString(_degrees) + "°"
 206                                         + (_minutes + _seconds / 60.0 + _fracs / 600.0); break;
 207                                 case FORMAT_DEG:
 208                                 case FORMAT_DEG_WITHOUT_CARDINAL: answer = (_asDouble<0.0?"-":"")
 209                                 + (_degrees + _minutes / 60.0 + _seconds / 3600.0 + _fracs / 36000.0); break;
 210                         }
 211                 }
 212                 return answer;
 213         }
 214
 215
 216         /**
 217          * Format an integer to a two-digit String
 218          * @param inNumber number to format
 219          * @return two-character String
 220          */
 221         private static String twoDigitString(int inNumber)
 222         {
 223                 if (inNumber <= 0) return "00";
 224                 if (inNumber < 10) return "0" + inNumber;
 225                 if (inNumber < 100) return "" + inNumber;
 226                 return "" + (inNumber % 100);
 227         }
 228
 229
 230         /**
 231          * Format an integer to a three-digit String for degrees
 232          * @param inNumber number to format
 233          * @return three-character String
 234          */
 235         private static String threeDigitString(int inNumber)
 236         {
 237                 if (inNumber <= 0) return "000";
 238                 if (inNumber < 10) return "00" + inNumber;
 239                 if (inNumber < 100) return "0" + inNumber;
 240                 return "" + (inNumber % 1000);
 241         }
 242
 243
 244         /**
 245          * Create a new Coordinate between two others
 246          * @param inStart start coordinate
 247          * @param inEnd end coordinate
 248          * @param inIndex index of point
 249          * @param inNumPoints number of points to interpolate
 250          * @return new Coordinate object
 251          */
 252         public static Coordinate interpolate(Coordinate inStart, Coordinate inEnd,
 253                 int inIndex, int inNumPoints)
 254         {
 255                 double startValue = inStart.getDouble();
 256                 double endValue = inEnd.getDouble();
 257                 double newValue = startValue + (endValue - startValue) * (inIndex+1) / (inNumPoints + 1);
 258                 Coordinate answer = inStart.makeNew(newValue, inStart._originalFormat);
 259                 return answer;
 260         }
 261
 262
 263         /**
 264          * Make a new Coordinate according to subclass
 265          * @param inValue double value
 266          * @param inFormat format to use
 267          * @return object of Coordinate subclass
 268          */
 269         protected abstract Coordinate makeNew(double inValue, int inFormat);
 270
 271
 272         /**
 273          * Create a String representation for debug
 274          */
 275         public String toString()
 276         {
 277                 return "Coord: " + _cardinal + " (" + _degrees + ") (" + _minutes + ") (" + _seconds + "." + _fracs + ") = " + _asDouble;
 278         }
 279 }