001 /**
002 *
003 */
004 package org.wdssii.core;
005
006 import java.util.Arrays;
007
008 /**
009 * @author lakshman
010 *
011 */
012 public class Radial {
013 private float[] values;
014
015 private final float startAzimuth;
016
017 private final float beamWidth;
018
019 private final float azimuthalSpacing;
020
021 private final float nyquist;
022
023 private final float gateWidth;
024
025 private CVector unitVector;
026
027 /** in degrees and kilometers. Does not copy array
028 * @param ny
029 * @param */
030 public Radial(float startAz, float beamWidth,
031 float azimuthalSpacing, float gateWidth,
032 float nyquist, float[] values) {
033 this.gateWidth = gateWidth;
034 this.values = values;
035 this.startAzimuth = startAz;
036 this.beamWidth = beamWidth;
037 this.azimuthalSpacing = azimuthalSpacing;
038 this.nyquist = nyquist;
039 }
040
041 /**
042 * Creates a completely separate copy of the data so that the master can change
043 * without affecting this value.
044 * @param radial
045 */
046 public Radial(Radial master) {
047 this.values = Arrays.copyOf(master.values, master.values.length);
048 this.startAzimuth = master.startAzimuth;
049 this.beamWidth = master.beamWidth;
050 this.azimuthalSpacing = master.azimuthalSpacing;
051 this.nyquist = master.nyquist;
052 this.gateWidth = master.gateWidth;
053 this.unitVector = master.unitVector;
054 }
055
056 /** puts the given angle in the range [0,360) */
057 public static float normalizeAzimuth(float az) {
058 // in range [0,360)
059 if (az < 0)
060 az += 360;
061 else if (az >= 360)
062 az -= 360;
063 return az;
064 }
065
066 public boolean contains(float az) {
067 // returns range [0,360)
068 float diff = normalizeAzimuth(az - startAzimuth);
069 return (diff < azimuthalSpacing);
070 }
071
072 public float[] getValues() {
073 return values;
074 }
075
076 /** returns a completely separate copy of the array. */
077 public float[] getClonedValues() {
078 float[] temp = new float[values.length];
079 for (int i = 0; i < values.length; ++i)
080 temp[i] = values[i];
081 return temp;
082 }
083
084 /** may not be normalized */
085 public float getStartAzimuth() {
086 return startAzimuth;
087 }
088
089 /**
090 * the end azimuth is not normalized in range [0,360) -- the rule instead is
091 * that the azimuth will be greater than the start azimuth.
092 */
093 public float getEndAzimuth() {
094 return (startAzimuth + azimuthalSpacing);
095 }
096
097 /**
098 * the mid azimuth is not normalized in range [0,360) -- the rule instead is
099 * that the azimuth will be greater than the start azimuth.
100 */
101 public float getMidAzimuth() {
102 return (float) (startAzimuth + 0.5 * azimuthalSpacing);
103 }
104
105 /** always positive */
106 public float getBeamWidth() {
107 return beamWidth;
108 }
109
110 public float getAzimuthalSpacing(){
111 return azimuthalSpacing;
112 }
113
114 /** in meters */
115 public float getGateWidthKms() {
116 return gateWidth;
117 }
118
119 public float getValue(int index) {
120 return values[index];
121 }
122
123 public int getNumGates() {
124 return values.length;
125 }
126
127 /** in m/s */
128 public float getNyquist(){
129 return nyquist;
130 }
131
132 /** range in kilometers. */
133 public double getRawValue(double range) {
134 int i = (int) Math.round(range / gateWidth);
135 if (i >= 0 && i < values.length)
136 return values[i];
137 else
138 return DataType.MissingData;
139 }
140
141 /**
142 * get the unit vector along the direction of this radial. This method will
143 * do the computation only on the first call, and return old values after
144 * that, so the elevation is not used after that.
145 */
146 public CVector getUnitVector(float elevation) {
147 if (unitVector == null) {
148 // unit vector in co-ordinate system tangential to
149 // earth at the radar location.
150 double angle_to_xdir = (90 - getMidAzimuth()) * Math.PI / 180.0;
151 unitVector = new CVector(Math.cos(angle_to_xdir), Math
152 .sin(angle_to_xdir), Math.sin(elevation * Math.PI / 180.0))
153 .unit();
154 return unitVector;
155 }
156 return unitVector;
157 }
158
159 /*
160 * @param elevation of the RadialSet @param gateno of point @param radar
161 * location of radar @param ux x-axis of local co-ordinate system tangential
162 * to earth's surface at radar location
163 */
164 public CPoint getLocation(float elevation, int gateno, CPoint radar,
165 CVector ux, CVector uy, CVector uz) {
166 CVector disp = getUnitVector(elevation).multiply(
167 gateno * getGateWidthKms() );
168 CVector disp_global = ux.multiply(disp.x).plus(uy.multiply(disp.y))
169 .plus(uz.multiply(disp.z));
170 CPoint result = radar.plus(disp_global);
171 return result;
172 }
173
174 /** debugging output */
175 public String toStringDB() {
176 String s = "Radial " + startAzimuth + " to " + getEndAzimuth() + " deg"
177 + " " + gateWidth + "km " + " first 10 values: \n";
178 for (int i = 0; i < 10; ++i)
179 s += getValue(i) + " ";
180 return (s + "\n");
181 }
182
183 }