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comparison geo-backend/src/main/java/de/intevation/gnv/geobackend/sde/datasources/RasterObject.java @ 548:ccd976fc0f7b

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Implemented bilinear interpolation on raster tiles. geo-backend/trunk@520 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Sascha L. Teichmann <sascha.teichmann@intevation.de>
date Sat, 09 Jan 2010 16:12:10 +0000
parents 23d5cc37dd5b
children 0dcf068fb552
comparison
equal deleted inserted replaced
547:23d5cc37dd5b 548:ccd976fc0f7b
87 87
88 public double getValue(Coordinate coordinate) { 88 public double getValue(Coordinate coordinate) {
89 return getValue(coordinate, NEAREST_NEIGHBOR); 89 return getValue(coordinate, NEAREST_NEIGHBOR);
90 } 90 }
91 91
92 public final double interpolateBilinear(double px, double py) {
93
94 if (px < 0.5d) { // left border
95 if (py < 0.5d) { // upper left edge
96 return rasterData[0];
97 }
98 if (py > tileHeight-0.5d) { // lower left edge
99 return rasterData[rasterData.length-tileWidth];
100 }
101 // center left
102 int i = (int)(py -= 0.5d);
103 double t = py - i;
104 i *= tileWidth;
105 return (1d-t)*rasterData[i] + t*rasterData[i+tileWidth];
106 }
107
108 if (px > tileWidth-0.5d) { // right border
109 if (py < 0.5d) { // upper right edge
110 return rasterData[tileWidth-1];
111 }
112 if (py > tileHeight-0.5d) { // lower right edge
113 return rasterData[rasterData.length-1];
114 }
115 // center right
116 int i = (int)(py -= 0.5d);
117 double t = py - i;
118 i = i*tileWidth + tileWidth-1;
119 return (1d-t)*rasterData[i] + t*rasterData[i+tileWidth];
120 }
121
122 if (py < 0.5d) { // top border
123 int i = (int)(px -= 0.5d);
124 double t = px - i;
125 return (1d-t)*rasterData[i] + t*rasterData[i+1];
126 }
127
128 if (py > tileHeight-0.5d) { // bottom border
129 int i = (int)(px -= 0.5d);
130 double t = px - i;
131 i += rasterData.length-tileWidth;
132 return (1d-t)*rasterData[i] + t*rasterData[i+1];
133 }
134
135 // center
136 int i = (int)(py -= 0.5d);
137 int j = (int)(px -= 0.5d);
138 double ti = py - i;
139 double tj = px - j;
140
141 int idx = i*tileWidth + j;
142
143 double v1j1 = rasterData[idx];
144 double v2j1 = rasterData[idx+1];
145
146 idx += tileWidth;
147
148 double v1j2 = rasterData[idx];
149 double v2j2 = rasterData[idx+1];
150
151 double v1 = (1d-tj)*v1j1 + tj*v2j1;
152 double v2 = (1d-tj)*v1j2 + tj*v2j2;
153
154 return (1d-ti)*v1 + ti*v2;
155 }
156
92 public double getValue(Coordinate coordinate, int interpolationType) { 157 public double getValue(Coordinate coordinate, int interpolationType) {
93 158
94 double px = mx*coordinate.x + bx; 159 double px = mx*coordinate.x + bx;
95 double py = my*coordinate.y + by; 160 double py = my*coordinate.y + by;
96 161
97 if (px < 0d || py < 0d || px >= tileWidth || py >= tileHeight) { 162 if (px < 0d || py < 0d || px >= tileWidth || py >= tileHeight) {
98 return Double.NaN; 163 return Double.NaN;
99 } 164 }
100 165
101 /*
102 if (interpolationType == BILINEAR) { 166 if (interpolationType == BILINEAR) {
103 // TODO: implement me! 167 return interpolateBilinear(px, py);
104 } 168 }
105 */
106 169
107 int posX = Math.min(tileWidth-1, (int)Math.round(px)); 170 int posX = Math.min(tileWidth-1, (int)Math.round(px));
108 int posY = Math.min(tileHeight-1, (int)Math.round(py)); 171 int posY = Math.min(tileHeight-1, (int)Math.round(py));
109 172
110 return get(posX, posY); 173 return get(posX, posY);
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