split channel attributes for Modis

Author: TomBlock

core/src/main/java/com/bc/fiduceo/reader/modis/MxD021KM_Reader.java

@@ -16,12 +16,11 @@
 import com.bc.fiduceo.reader.time.TimeLocator;
 import com.bc.fiduceo.reader.time.TimeLocator_TAI1993Scan;
 import com.bc.fiduceo.util.NetCDFUtils;
-import com.bc.fiduceo.util.TimeUtils;
-import ucar.ma2.Array;
-import ucar.ma2.ArrayInt;
-import ucar.ma2.InvalidRangeException;
-import ucar.ma2.MAMath;
+import org.esa.snap.core.util.StringUtils;
+import ucar.ma2.*;
+import ucar.ma2.DataType;
 import ucar.nc2.Attribute;
+import ucar.nc2.AttributeContainer;
 import ucar.nc2.Structure;
 import ucar.nc2.Variable;
 
@@ -31,8 +30,6 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Date;
 import java.util.List;
 
 import static com.bc.fiduceo.reader.modis.ModisConstants.LATITUDE_VAR_NAME;
@@ -483,4 +480,44 @@ private void injectThermalNoiseVariables() throws IOException {
             arrayCache.inject(new ThermalNoiseVariable(noiseVariable, i, productSize.getNy()));
         }
     }
+
+    @SuppressWarnings("ConstantConditions")
+    @Override
+    protected void splitAttributes(Variable channelVariable, int index, int numChannels) {
+        final ArrayList<Attribute> toRemove = new ArrayList<>();
+        final ArrayList<Attribute> toAdd = new ArrayList<>();
+
+        final AttributeContainer attributes = channelVariable.attributes();
+        for (Attribute attribute : attributes) {
+            toRemove.add(attribute);
+
+            final DataType dataType = attribute.getDataType();
+            if (dataType.isString()) {
+                final String stringValue = attribute.getStringValue();
+                final String[] tokens = StringUtils.split(stringValue, new char[]{','}, true);
+                if (tokens.length == numChannels) {
+                    final Attribute newAttribute = new Attribute(attribute.getShortName(), tokens[index]);
+                    toAdd.add(newAttribute);
+                } else {
+                    toAdd.add(attribute);
+                }
+            } else if (dataType.isNumeric()) {
+                final int length = attribute.getLength();
+                if (length == numChannels) {
+                    final Number numericValue = attribute.getNumericValue(index);
+                    final Attribute newAttribute = new Attribute(attribute.getShortName(), numericValue);
+                    toAdd.add(newAttribute);
+                } else {
+                    toAdd.add(attribute);
+                }
+            }
+        }
+
+        for (Attribute attribute : toRemove) {
+            attributes.remove(attribute);
+        }
+        for (Attribute attribute : toAdd) {
+            attributes.addAttribute(attribute);
+        }
+    }
 }

core/src/main/java/com/bc/fiduceo/reader/netcdf/NetCDFReader.java

@@ -150,11 +150,16 @@ private void addChannelVariables(List<Variable> result, Variable variable, int n
             final Variable channelVariable = variable.section(section);
             final String channelVariableName = variableBaseName + layerExtension.getExtension(channel);
             channelVariable.setName(channelVariableName);
+            splitAttributes(channelVariable, channel, numChannels);
             result.add(channelVariable);
             origin[channel_dimension_index]++;
         }
     }
 
+    protected void splitAttributes(Variable channelVariable, int index, int numChannels) {
+        // nothing to do here. If required, readers may override this method tb 2020-11-25
+    }
+
     protected Array acquisitionTimeFromTimeLocator(int y, Interval interval) throws IOException {
         final int height = interval.getY();
         final int width = interval.getX();

core/src/test/java/com/bc/fiduceo/reader/modis/MxD021KM_Reader_IO_Test.java

@@ -204,18 +204,22 @@ public void testGetVariables_Terra() throws IOException, InvalidRangeException {
         variable = variables.get(18);
         assertEquals("EV_1KM_RefSB_ch10", variable.getShortName());
         assertEquals(DataType.USHORT, variable.getDataType());
+        NCTestUtils.assertAttribute(variable, "radiance_scales", "0.0036217605");
 
         variable = variables.get(34);
         assertEquals("EV_1KM_RefSB_Uncert_Indexes_ch11", variable.getShortName());
         assertEquals(DataType.UBYTE, variable.getDataType());
+        NCTestUtils.assertAttribute(variable, "specified_uncertainty", "1.5");
 
         variable = variables.get(48);
         assertEquals("EV_1KM_Emissive_ch22", variable.getShortName());
         assertEquals(DataType.USHORT, variable.getDataType());
+        NCTestUtils.assertAttribute(variable, "band_names", "22");
 
         variable = variables.get(65);
         assertEquals("EV_1KM_Emissive_Uncert_Indexes_ch23", variable.getShortName());
         assertEquals(DataType.UBYTE, variable.getDataType());
+        NCTestUtils.assertAttribute(variable, "scaling_factor", "4.0");
 
         variable = variables.get(69);
         assertEquals("EV_1KM_Emissive_Uncert_Indexes_ch28", variable.getShortName());