apply_dimension(dim=bands) => do not filter out all nodata tiles

openeo-geotrellis/src/main/scala/org/openeo/geotrellis/OpenEOProcesses.scala

@@ -561,11 +561,15 @@ class OpenEOProcesses extends Serializable {
     return ContextRDD(new org.apache.spark.rdd.PairRDDFunctions[K,MultibandTile](datacube).mapValues(tile => {
       if (!tile.isInstanceOf[EmptyMultibandTile]) {
         val resultTiles = function(tile.bands)
-        MultibandTile(resultTiles)
+        if(resultTiles.exists(!_.isNoDataTile)){
+          MultibandTile(resultTiles)
+        }else{
+          new EmptyMultibandTile(tile.cols,tile.rows,tile.cellType,resultTiles.length)
+        }
       }else{
-        tile
+        tile//at this point, the band count of the empty tile may be wrong
       }
-    }).filter(_._2.bands.exists(!_.isNoDataTile)),datacube.metadata.copy(cellType = scriptBuilder.getOutputCellType()))
+    }),datacube.metadata.copy(cellType = scriptBuilder.getOutputCellType()))
   }
 
   def filterEmptyTile[K:ClassTag](datacube:MultibandTileLayerRDD[K]): RDD[(K, MultibandTile)] with Metadata[TileLayerMetadata[K]]={

openeo-geotrellis/src/test/java/org/openeo/geotrellis/TestOpenEOProcesses.java

@@ -12,11 +12,14 @@
 import org.apache.spark.SparkContext;
 import org.apache.spark.api.java.JavaPairRDD;
 import org.apache.spark.api.java.JavaPairRDD$;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.api.java.function.Function;
 import org.apache.spark.rdd.RDD;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.jupiter.api.DisplayName;
+import scala.Function1;
 import scala.Option;
 import scala.Tuple2;
 import scala.collection.JavaConversions;
@@ -54,24 +57,6 @@ public static void shutDownSparkContext() {
     }
 
 
-    @DisplayName("Test combining all bands.")
-    @Test
-    public void testMapBands() {
-        OpenEOProcessScriptBuilder processBuilder = TestOpenEOProcessScriptBuilder.createNormalizedDifferenceProcess10AddXY();
-        assertEquals(FloatConstantNoDataCellType$.MODULE$,processBuilder.getOutputCellType());
-        Tile tile0 = new UByteConstantTile((byte)3,256,256, (UByteCells)  CellType$.MODULE$.fromName("uint8"));
-        Tile tile1 = new UByteConstantTile((byte)1,256,256, (UByteCells) CellType$.MODULE$.fromName("uint8"));
-        RDD<Tuple2<SpatialKey, MultibandTile>> datacube = TileLayerRDDBuilders$.MODULE$.createMultibandTileLayerRDD(SparkContext.getOrCreate(), new ArrayMultibandTile(new Tile[]{tile0,tile1}), new TileLayout(1, 1, 256, 256));
-        ClassTag<SpatialKey> tag = scala.reflect.ClassTag$.MODULE$.apply(SpatialKey.class);
-        ContextRDD<SpatialKey, MultibandTile, TileLayerMetadata<SpatialKey>> ndviDatacube = (ContextRDD<SpatialKey, MultibandTile, TileLayerMetadata<SpatialKey>>) new OpenEOProcesses().<SpatialKey>mapBandsGeneric(datacube, processBuilder, new HashMap<>(), tag);
-        assertEquals(FloatConstantNoDataCellType$.MODULE$,ndviDatacube.metadata().cellType());
-        List<Tuple2<SpatialKey, MultibandTile>> result = ndviDatacube.toJavaRDD().collect();
-        assertEquals(FloatConstantNoDataCellType$.MODULE$,result.get(0)._2.cellType());
-        System.out.println("result = " + result);
-        assertEquals(1, result.get(0)._2().bandCount());
-        double[] doubles = result.get(0)._2().band(0).toArrayDouble();
-        assertEquals(0.5,doubles[0],0.0);
-    }
 
     @Test
     public void testMapToIntervals() {

openeo-geotrellis/src/test/scala/org/openeo/geotrellis/OpenEOProcessesSpec.scala

@@ -20,7 +20,7 @@ import org.apache.hadoop.security.UserGroupInformation
 import org.apache.spark.rdd.RDD
 import org.apache.spark.{SparkConf, SparkContext}
 import org.junit.Assert._
-import org.junit.jupiter.api.{AfterAll, BeforeAll}
+import org.junit.jupiter.api.{AfterAll, BeforeAll, DisplayName}
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.Arguments.arguments
 import org.junit.jupiter.params.provider.{Arguments, EnumSource, MethodSource}
@@ -598,4 +598,34 @@ class OpenEOProcessesSpec extends RasterMatchers {
 
   }
 
+  @DisplayName("Test combining all bands.")
+  @Test def testMapBands(): Unit = {
+    val processBuilder = TestOpenEOProcessScriptBuilder.createNormalizedDifferenceProcess10AddXY
+    assertEquals(FloatConstantNoDataCellType, processBuilder.getOutputCellType)
+    val inputCellType = UByteConstantNoDataCellType
+    val tile0 = new UByteConstantTile(3.toByte, 256, 256, inputCellType)
+    val tile1 = new UByteConstantTile(1.toByte, 256, 256, inputCellType)
+    val datacube = TileLayerRDDBuilders.createMultibandTileLayerRDD(SparkContext.getOrCreate, new ArrayMultibandTile(Array[Tile](tile0, tile1)), new TileLayout(4, 4, 64, 64))
+    val withEmptyTiles = datacube.withContext{_.map((v1: Tuple2[SpatialKey, MultibandTile]) => {
+      if (v1._1 == new SpatialKey(1, 0)) {
+        val tile = v1._2
+        new Tuple2[SpatialKey, MultibandTile](v1._1, new EmptyMultibandTile(tile.cols, tile.rows, tile.cellType, tile.bandCount))
+      }
+      else v1
+    })}
+
+    val ndviDatacube = new OpenEOProcesses().mapBandsGeneric[SpatialKey](withEmptyTiles, processBuilder, new util.HashMap[String, Any])
+    assertEquals(FloatConstantNoDataCellType, ndviDatacube.metadata.cellType)
+    val result = ndviDatacube.collectAsMap()
+    val key0 = SpatialKey(0, 0)
+    assertEquals(FloatConstantNoDataCellType, result(key0).cellType)
+    System.out.println("result = " + result)
+    assertEquals(1, result(key0).bandCount)
+    val doubles = result(key0).band(0).toArrayDouble
+    assertEquals(0.5, doubles(0), 0.0)
+    assertTrue(result(SpatialKey(1,0)).isInstanceOf[EmptyMultibandTile])
+    // this test fails, because ndvi function doesn't really know the band count
+    //assertEquals(1,result(SpatialKey(1,0)).bandCount)
+  }
+
 }