001 /**
002 *
003 */
004 package org.wdssii.core;
005
006 import java.util.Date;
007
008 import org.apache.commons.logging.Log;
009 import org.apache.commons.logging.LogFactory;
010
011 import ucar.units.ConversionException;
012 import ucar.units.Converter;
013 import ucar.units.Unit;
014
015 /**
016 *
017 * A regularly spaced grid where the first dimension is latitude and the second dimension is longitude.
018 * The (0,0) location is the north-west corner. In the first dimension, latitude decreases (southward)
019 * and in the second dimension, longitude increases (eastward).
020 *
021 * @author lakshman
022 *
023 */
024 public class LatLonGrid extends DataType {
025 private static Log log = LogFactory.getLog(LatLonGrid.class);
026 private final float deltaLat, deltaLon;
027 private float[][] values;
028
029 /** {@inheritDoc} */
030 public LatLonGrid(LatLonGrid master){
031 super(master);
032 deltaLat = master.deltaLat;
033 deltaLon = master.deltaLon;
034 values = copyOf(master.values);
035 }
036
037 public LatLonGrid(Location nwCorner, Date time, String typeName, float deltaLat, float deltaLon, float[][] values){
038 super(nwCorner, time, typeName);
039 this.deltaLat = deltaLat;
040 this.deltaLon = deltaLon;
041 this.values = values;
042 }
043
044 /** All the values are initialized to zero */
045 public LatLonGrid(Location nwCorner, Date time, String typeName, float deltaLat, float deltaLon, int numLat, int numLon){
046 this(nwCorner, time, typeName, deltaLat, deltaLon, new float[numLat][numLon] );
047 }
048
049 public float[][] getValues(){
050 return values;
051 }
052
053 public int getNumLat(){
054 return values.length;
055 }
056
057 public int getNumLon(){
058 if ( values.length == 0 ){
059 return 0;
060 } else {
061 return values[0].length;
062 }
063 }
064
065 /** positive number that indicates the size of a pixel in lat-direction */
066 public float getDeltaLat(){
067 return deltaLat;
068 }
069
070 /** positive number that indicates the size of a pixel in lon-direction */
071 public float getDeltaLon(){
072 return deltaLon;
073 }
074
075 /** Converts all the values in this grid to the specified unit.
076 * @see UdUnits.parse()
077 * @param grid
078 * @param toUnit Use UdUnits.parse() to create this Unit
079 */
080 public void convertToUnit(Unit toUnit) {
081 if (this.getUnit() == null) {
082 log.debug("Missing units in " + this.getTypeName() + " assuming "
083 + toUnit);
084 return;
085 }
086 Unit gridUnit = UdUnits.parse(this.getUnit());
087 if (gridUnit.equals(toUnit)) {
088 return;
089 }
090 try {
091 Converter converter = gridUnit.getConverterTo(toUnit);
092 float[][] values = this.getValues();
093 for (int i = 0; i < values.length; ++i) {
094 for (int j = 0; j < values.length; ++j) {
095 values[i][j] = converter.convert(values[i][j]);
096 }
097 }
098 } catch (ConversionException e) {
099 log.error("Unit in " + this.getTypeName() + " is " + gridUnit
100 + "; expected something compatible with " + toUnit);
101 }
102 }
103
104 /** Get the value at a Location. The height is ignored and MissingData is returned for values outside */
105 public float getValue(Location loc){
106 try{
107 // not reusing Pixel code since this is more efficient
108 int i = (int) Math.rint( (this.getLocation().getLatitude() - loc.getLatitude()) / this.deltaLat);
109 int j = (int) Math.rint( (loc.getLongitude() - this.getLocation().getLongitude()) / this.deltaLon);
110 return values[i][j];
111 } catch(Exception e) {
112 return DataType.MissingData;
113 }
114 }
115
116 /** returns the Pixel corresponding to the location. The height is ignored but a null value is
117 * returned if the location is outside the grid.
118 */
119 public Pixel getPixel(Location loc){
120 int i = (int) Math.rint( (this.getLocation().getLatitude() - loc.getLatitude()) / this.deltaLat);
121 int j = (int) Math.rint( (loc.getLongitude() - this.getLocation().getLongitude()) / this.deltaLon);
122 if ( i >= 0 && i < getNumLat() && j >= 0 && j < getNumLon() ){
123 return new Pixel(i,j);
124 } else {
125 return null;
126 }
127 }
128
129 public float getValue(Pixel p){
130 return values[p.x][p.y];
131 }
132
133 public static class Pixel {
134 public int x;
135 public int y;
136 public Pixel(int x, int y){
137 this.x = x;
138 this.y = y;
139 }
140 }
141
142 /** Can be used to set all the values of the grid at once. */
143 public void setValues(float[][] values2) {
144 values = values2;
145 }
146 }