Fix Cell Statistics NoData handling

Fixes #40092
qgis · Nov 17, 2020 · 13a43de · 13a43de
1 parent a503047
commit 13a43de
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Showing 4 changed files with 27 additions and 1 deletion.
diff --git a/src/analysis/processing/qgsalgorithmcellstatistics.cpp b/src/analysis/processing/qgsalgorithmcellstatistics.cpp
@@ -277,7 +277,7 @@ QVariantMap QgsCellStatisticsAlgorithm::processAlgorithm( const QVariantMap &par
             outputBlock->setValue( row, col, mNoDataValue );
           }
         }
-        else if ( !noDataInStack || mIgnoreNoData )
+        else if ( !noDataInStack || ( mIgnoreNoData && cellValueStackSize > 0 ) )
         {
           switch ( method )
           {
@@ -320,6 +320,11 @@ QVariantMap QgsCellStatisticsAlgorithm::processAlgorithm( const QVariantMap &par
           }
           outputBlock->setValue( row, col, result );
         }
+        else
+        {
+          //result is NoData if cellValueStack contains no valid values, eg. all cellValues are NoData
+          outputBlock->setValue( row, col, mNoDataValue );
+        }
       }
     }
     provider->writeBlock( outputBlock.get(), 1, iterLeft, iterTop );

diff --git a/tests/src/analysis/testqgsprocessingalgs.cpp b/tests/src/analysis/testqgsprocessingalgs.cpp
@@ -2360,6 +2360,17 @@ void TestQgsProcessingAlgs::cellStatistics_data()
       << QStringLiteral( "/cellstatistics_median_result_fourLayers_float32.tif" )
       << Qgis::Float32;
 
+  /*
+   * Testcase 19: sum with raster cell stacks containing only nodata
+   */
+  QTest::newRow( "testcase_19" )
+      << QStringList( {"/raster/statisticsRas1_float64.asc", "/raster/statisticsRas1_float64.asc"} )
+      << QStringLiteral( "/raster/statisticsRas3_int32.tif" )
+      << 0
+      << true
+      << QStringLiteral( "/cellstatistics_sum_result_ignoreNoData.tif" )
+      << Qgis::Float64;
+
 }
 
 void TestQgsProcessingAlgs::cellStatistics()

diff --git a/...estdata/control_images/expected_cellStatistics/cellstatistics_sum_result_ignoreNoData.tif b/...estdata/control_images/expected_cellStatistics/cellstatistics_sum_result_ignoreNoData.tif
diff --git a/tests/testdata/raster/statisticsRas4_float64.asc b/tests/testdata/raster/statisticsRas4_float64.asc
@@ -0,0 +1,10 @@
+ncols        4
+nrows        4
+xllcorner    0
+yllcorner    0
+cellsize     1
+nodata_value -9999.0
+ 1.0 1.0 0.0 0.0
+ -9999.0 1.0 2.0 2.0
+ 4.0 0.0 0.0 2.0
+ 4.0 0.0 1.0 1.0