|
| 1 | +/*************************************************************************** |
| 2 | + qgszonalstatistics.cpp - description |
| 3 | + ---------------------------- |
| 4 | + begin : August 29th, 2009 |
| 5 | + copyright : (C) 2009 by Marco Hugentobler |
| 6 | + email : marco at hugis dot net |
| 7 | + ***************************************************************************/ |
| 8 | + |
| 9 | +/*************************************************************************** |
| 10 | + * * |
| 11 | + * This program is free software; you can redistribute it and/or modify * |
| 12 | + * it under the terms of the GNU General Public License as published by * |
| 13 | + * the Free Software Foundation; either version 2 of the License, or * |
| 14 | + * (at your option) any later version. * |
| 15 | + * * |
| 16 | + ***************************************************************************/ |
| 17 | + |
| 18 | +#include "qgszonalstatistics.h" |
| 19 | +#include "qgsgeometry.h" |
| 20 | +#include "qgsvectordataprovider.h" |
| 21 | +#include "qgsvectorlayer.h" |
| 22 | +#include "gdal.h" |
| 23 | +#include "cpl_string.h" |
| 24 | +#include <QProgressDialog> |
| 25 | + |
| 26 | +QgsZonalStatistics::QgsZonalStatistics(QgsVectorLayer* polygonLayer, const QString& rasterFile, const QString& attributePrefix, int rasterBand): \ |
| 27 | + mRasterFilePath(rasterFile), mRasterBand(rasterBand), mPolygonLayer(polygonLayer), mAttributePrefix(attributePrefix), mInputNodataValue( -1 ) |
| 28 | +{ |
| 29 | + |
| 30 | +} |
| 31 | + |
| 32 | +QgsZonalStatistics::QgsZonalStatistics(): mRasterBand(0), mPolygonLayer(0) |
| 33 | +{ |
| 34 | + |
| 35 | +} |
| 36 | + |
| 37 | +QgsZonalStatistics::~QgsZonalStatistics() |
| 38 | +{ |
| 39 | + |
| 40 | +} |
| 41 | + |
| 42 | +int QgsZonalStatistics::calculateStatistics(QProgressDialog* p) |
| 43 | +{ |
| 44 | + if(!mPolygonLayer || !mPolygonLayer->geometryType() == QGis::Polygon) |
| 45 | + { |
| 46 | + return 1; |
| 47 | + } |
| 48 | + |
| 49 | + QgsVectorDataProvider* vectorProvider = mPolygonLayer->dataProvider(); |
| 50 | + if(!vectorProvider) |
| 51 | + { |
| 52 | + return 2; |
| 53 | + } |
| 54 | + |
| 55 | + //open the raster layer and the raster band |
| 56 | + GDALAllRegister(); |
| 57 | + GDALDatasetH inputDataset = GDALOpen(mRasterFilePath.toLocal8Bit().data(), GA_ReadOnly ); |
| 58 | + if ( inputDataset == NULL ) |
| 59 | + { |
| 60 | + return 3; |
| 61 | + } |
| 62 | + |
| 63 | + if ( GDALGetRasterCount( inputDataset ) < (mRasterBand - 1) ) |
| 64 | + { |
| 65 | + GDALClose( inputDataset ); |
| 66 | + return 4; |
| 67 | + } |
| 68 | + |
| 69 | + GDALRasterBandH rasterBand = GDALGetRasterBand( inputDataset, mRasterBand ); |
| 70 | + if ( rasterBand == NULL ) |
| 71 | + { |
| 72 | + GDALClose( inputDataset ); |
| 73 | + return 5; |
| 74 | + } |
| 75 | + mInputNodataValue = GDALGetRasterNoDataValue( rasterBand, NULL ); |
| 76 | + |
| 77 | + //get geometry info about raster layer |
| 78 | + int nCellsX = GDALGetRasterXSize( inputDataset ); |
| 79 | + int nCellsY = GDALGetRasterYSize( inputDataset ); |
| 80 | + double geoTransform[6]; |
| 81 | + if ( GDALGetGeoTransform( inputDataset, geoTransform ) != CE_None ) |
| 82 | + { |
| 83 | + GDALClose( inputDataset ); |
| 84 | + return 6; |
| 85 | + } |
| 86 | + double cellsizeX = geoTransform[1]; |
| 87 | + if(cellsizeX < 0) |
| 88 | + { |
| 89 | + cellsizeX = -cellsizeX; |
| 90 | + } |
| 91 | + double cellsizeY = geoTransform[5]; |
| 92 | + if(cellsizeY < 0) |
| 93 | + { |
| 94 | + cellsizeY = -cellsizeY; |
| 95 | + } |
| 96 | + QgsRectangle rasterBBox(geoTransform[0], geoTransform[3] - (nCellsY * cellsizeY), geoTransform[0] + (nCellsX * cellsizeX), geoTransform[3]); |
| 97 | + |
| 98 | + //add the new count, sum, mean fields to the provider |
| 99 | + QList<QgsField> newFieldList; |
| 100 | + QgsField countField(mAttributePrefix + "count", QVariant::Int); |
| 101 | + QgsField sumField(mAttributePrefix + "sum", QVariant::Double); |
| 102 | + QgsField meanField(mAttributePrefix + "mean", QVariant::Double); |
| 103 | + newFieldList.push_back(countField); |
| 104 | + newFieldList.push_back(sumField); |
| 105 | + newFieldList.push_back(meanField); |
| 106 | + if(!vectorProvider->addAttributes( newFieldList )) |
| 107 | + { |
| 108 | + return 7; |
| 109 | + } |
| 110 | + |
| 111 | + //index of the new fields |
| 112 | + int countIndex = vectorProvider->fieldNameIndex(mAttributePrefix + "count"); |
| 113 | + int sumIndex = vectorProvider->fieldNameIndex(mAttributePrefix + "sum"); |
| 114 | + int meanIndex = vectorProvider->fieldNameIndex(mAttributePrefix + "mean"); |
| 115 | + |
| 116 | + if (countIndex == -1 || sumIndex == -1 || meanIndex == -1) |
| 117 | + { |
| 118 | + return 8; |
| 119 | + } |
| 120 | + |
| 121 | + //progress dialog |
| 122 | + long featureCount = vectorProvider->featureCount(); |
| 123 | + if(p) |
| 124 | + { |
| 125 | + p->setMaximum(featureCount); |
| 126 | + } |
| 127 | + |
| 128 | + |
| 129 | + //iterate over each polygon |
| 130 | + vectorProvider->select(QgsAttributeList(), QgsRectangle(), true, false); |
| 131 | + vectorProvider->rewind(); |
| 132 | + QgsFeature f; |
| 133 | + double count = 0; |
| 134 | + double sum = 0; |
| 135 | + double mean = 0; |
| 136 | + float* scanLine; |
| 137 | + int featureCounter = 0; |
| 138 | + //x- and y- coordinate of current cell |
| 139 | + double cellCenterX = 0; |
| 140 | + double cellCenterY = 0; |
| 141 | + QgsPoint currentCellCenter; |
| 142 | + |
| 143 | + while(vectorProvider->nextFeature(f)) |
| 144 | + { |
| 145 | + if(p) |
| 146 | + { |
| 147 | + p->setValue(featureCounter); |
| 148 | + } |
| 149 | + |
| 150 | + if(p && p->wasCanceled()) |
| 151 | + { |
| 152 | + break; |
| 153 | + } |
| 154 | + |
| 155 | + QgsGeometry* featureGeometry = f.geometry(); |
| 156 | + if(!featureGeometry) |
| 157 | + { |
| 158 | + ++featureCounter; |
| 159 | + continue; |
| 160 | + } |
| 161 | + |
| 162 | + int offsetX, offsetY, nCellsX, nCellsY; |
| 163 | + if(cellInfoForBBox(rasterBBox, featureGeometry->boundingBox(), cellsizeX, cellsizeY, offsetX, offsetY, nCellsX, nCellsY) != 0) |
| 164 | + { |
| 165 | + ++featureCounter; |
| 166 | + continue; |
| 167 | + } |
| 168 | + |
| 169 | + scanLine = ( float * ) CPLMalloc( sizeof( float ) * nCellsX ); |
| 170 | + cellCenterY = rasterBBox.yMaximum() - offsetY * cellsizeY - cellsizeY / 2; |
| 171 | + count = 0; |
| 172 | + sum = 0; |
| 173 | + float currentValue; |
| 174 | + |
| 175 | + for(int i = 0; i < nCellsY; ++i) |
| 176 | + { |
| 177 | + GDALRasterIO( rasterBand, GF_Read, offsetX, offsetY + i, nCellsX, 1, scanLine, nCellsX, 1, GDT_Float32, 0, 0 ); |
| 178 | + cellCenterX = rasterBBox.xMinimum() + offsetX * cellsizeX + cellsizeX / 2; |
| 179 | + for(int j = 0; j < nCellsX; ++j) |
| 180 | + { |
| 181 | + currentCellCenter = QgsPoint(cellCenterX, cellCenterY); |
| 182 | + if(featureGeometry->contains(¤tCellCenter)) |
| 183 | + { |
| 184 | + if(scanLine[j] != mInputNodataValue) //don't consider nodata values |
| 185 | + { |
| 186 | + sum += scanLine[j]; |
| 187 | + ++count; |
| 188 | + } |
| 189 | + } |
| 190 | + cellCenterX += cellsizeX; |
| 191 | + } |
| 192 | + cellCenterY -= cellsizeY; |
| 193 | + } |
| 194 | + |
| 195 | + if(count == 0) |
| 196 | + { |
| 197 | + mean = 0; |
| 198 | + } |
| 199 | + else |
| 200 | + { |
| 201 | + mean = sum / count; |
| 202 | + } |
| 203 | + |
| 204 | + //write the new AEY value to the vector data provider |
| 205 | + QgsChangedAttributesMap changeMap; |
| 206 | + QgsAttributeMap changeAttributeMap; |
| 207 | + changeAttributeMap.insert(countIndex, QVariant(count)); |
| 208 | + changeAttributeMap.insert(sumIndex, QVariant(sum)); |
| 209 | + changeAttributeMap.insert(meanIndex, QVariant(mean)); |
| 210 | + changeMap.insert(f.id(), changeAttributeMap); |
| 211 | + vectorProvider->changeAttributeValues(changeMap); |
| 212 | + |
| 213 | + CPLFree(scanLine); |
| 214 | + ++featureCounter; |
| 215 | + } |
| 216 | + |
| 217 | + if(p) |
| 218 | + { |
| 219 | + p->setValue(featureCount); |
| 220 | + } |
| 221 | + |
| 222 | + GDALClose( inputDataset ); |
| 223 | + return 0; |
| 224 | +} |
| 225 | + |
| 226 | +int QgsZonalStatistics::cellInfoForBBox(const QgsRectangle& rasterBBox, const QgsRectangle& featureBBox, double cellSizeX, double cellSizeY, \ |
| 227 | + int& offsetX, int& offsetY, int& nCellsX, int& nCellsY) const |
| 228 | +{ |
| 229 | + //get intersecting bbox |
| 230 | + QgsRectangle intersectBox = rasterBBox.intersect(&featureBBox); |
| 231 | + if(intersectBox.isEmpty()) |
| 232 | + { |
| 233 | + nCellsX = 0; nCellsY = 0; offsetX = 0; offsetY = 0; |
| 234 | + return 0; |
| 235 | + } |
| 236 | + |
| 237 | + //get offset in pixels in x- and y- direction |
| 238 | + offsetX = (int)( (intersectBox.xMinimum() - rasterBBox.xMinimum()) / cellSizeX); |
| 239 | + offsetY = (int)( (rasterBBox.yMaximum() - intersectBox.yMaximum()) / cellSizeY); |
| 240 | + |
| 241 | + int maxColumn = (int) ( (intersectBox.xMaximum() - rasterBBox.xMinimum()) / cellSizeX) + 1; |
| 242 | + int maxRow = (int) ( (rasterBBox.yMaximum() - intersectBox.yMinimum()) / cellSizeY ) + 1; |
| 243 | + |
| 244 | + nCellsX = maxColumn - offsetX; |
| 245 | + nCellsY = maxRow - offsetY; |
| 246 | + |
| 247 | + return 0; |
| 248 | +} |
| 249 | + |
| 250 | + |
| 251 | + |
| 252 | + |
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