Mercurial > dive4elements > gnv-client
changeset 548:ccd976fc0f7b
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 |
| files | geo-backend/ChangeLog geo-backend/src/main/java/de/intevation/gnv/geobackend/sde/datasources/RasterObject.java |
| diffstat | 2 files changed, 71 insertions(+), 3 deletions(-) [+] |
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--- a/geo-backend/ChangeLog Sat Jan 09 12:41:26 2010 +0000 +++ b/geo-backend/ChangeLog Sat Jan 09 16:12:10 2010 +0000 @@ -1,3 +1,8 @@ +2009-01-09 Sascha L. Teichmann <sascha.teichmann@intevation.de> + + * src/main/java/de/intevation/gnv/geobackend/sde/datasources/RasterObject.java: + Implemented bilinear interpolation. + 2009-01-09 Sascha L. Teichmann <sascha.teichmann@intevation.de> * src/main/java/de/intevation/gnv/geobackend/sde/datasources/ArcSDEStatement.java:
--- a/geo-backend/src/main/java/de/intevation/gnv/geobackend/sde/datasources/RasterObject.java Sat Jan 09 12:41:26 2010 +0000 +++ b/geo-backend/src/main/java/de/intevation/gnv/geobackend/sde/datasources/RasterObject.java Sat Jan 09 16:12:10 2010 +0000 @@ -89,6 +89,71 @@ return getValue(coordinate, NEAREST_NEIGHBOR); } + public final double interpolateBilinear(double px, double py) { + + if (px < 0.5d) { // left border + if (py < 0.5d) { // upper left edge + return rasterData[0]; + } + if (py > tileHeight-0.5d) { // lower left edge + return rasterData[rasterData.length-tileWidth]; + } + // center left + int i = (int)(py -= 0.5d); + double t = py - i; + i *= tileWidth; + return (1d-t)*rasterData[i] + t*rasterData[i+tileWidth]; + } + + if (px > tileWidth-0.5d) { // right border + if (py < 0.5d) { // upper right edge + return rasterData[tileWidth-1]; + } + if (py > tileHeight-0.5d) { // lower right edge + return rasterData[rasterData.length-1]; + } + // center right + int i = (int)(py -= 0.5d); + double t = py - i; + i = i*tileWidth + tileWidth-1; + return (1d-t)*rasterData[i] + t*rasterData[i+tileWidth]; + } + + if (py < 0.5d) { // top border + int i = (int)(px -= 0.5d); + double t = px - i; + return (1d-t)*rasterData[i] + t*rasterData[i+1]; + } + + if (py > tileHeight-0.5d) { // bottom border + int i = (int)(px -= 0.5d); + double t = px - i; + i += rasterData.length-tileWidth; + return (1d-t)*rasterData[i] + t*rasterData[i+1]; + } + + // center + int i = (int)(py -= 0.5d); + int j = (int)(px -= 0.5d); + double ti = py - i; + double tj = px - j; + + int idx = i*tileWidth + j; + + double v1j1 = rasterData[idx]; + double v2j1 = rasterData[idx+1]; + + idx += tileWidth; + + double v1j2 = rasterData[idx]; + double v2j2 = rasterData[idx+1]; + + double v1 = (1d-tj)*v1j1 + tj*v2j1; + double v2 = (1d-tj)*v1j2 + tj*v2j2; + + return (1d-ti)*v1 + ti*v2; + } + public double getValue(Coordinate coordinate, int interpolationType) { double px = mx*coordinate.x + bx; @@ -98,11 +163,9 @@ return Double.NaN; } - /* if (interpolationType == BILINEAR) { - // TODO: implement me! + return interpolateBilinear(px, py); } - */ int posX = Math.min(tileWidth-1, (int)Math.round(px)); int posY = Math.min(tileHeight-1, (int)Math.round(py));