Enable uduints based time coordinates on scan aggregations

cdm/core/src/main/java/ucar/nc2/internal/ncml/AggDatasetOuter.java

@@ -1,4 +1,8 @@
-/* Copyright Unidata */
+/*
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
+ * See LICENSE.txt for license information.
+ */
+
 package ucar.nc2.internal.ncml;
 
 import java.io.IOException;
@@ -11,6 +15,7 @@
 import javax.annotation.Nullable;
 import thredds.inventory.MFile;
 import ucar.ma2.Array;
+import ucar.ma2.DataType;
 import ucar.ma2.InvalidRangeException;
 import ucar.ma2.Range;
 import ucar.ma2.Section;
@@ -32,7 +37,8 @@ class AggDatasetOuter extends AggDataset {
   @Nullable
   final String coordValue; // if theres a coordValue on the netcdf element - may be multiple, blank separated
   final Date coordValueDate; // if its a date
-  final boolean isStringValued; // if coordinat is a String
+  final DataType coordDataType; // coordinate data type
+  final String coordUdunit; // coordinate udunit string, if numeric
 
   // not final because of deffered read
   int ncoord; // number of coordinates in outer dimension
@@ -68,18 +74,18 @@ class AggDatasetOuter extends AggDataset {
       }
     }
 
-    boolean isString = false;
+    DataType aggCoordDataType = DataType.DOUBLE;
     if ((aggregationOuter.type == Type.joinNew) || (aggregationOuter.type == Type.joinExistingOne)
         || (aggregationOuter.type == Type.forecastModelRunCollection)) {
       if (coordValueS == null) {
         coordValueS = extractCoordNameFromFilename(this.getLocation());
-        isString = true;
+        aggCoordDataType = DataType.STRING;
       } else {
         // we just need to know if its string valued
         try {
           Double.parseDouble(coordValueS);
         } catch (NumberFormatException e) {
-          isString = true;
+          aggCoordDataType = DataType.STRING;
         }
       }
     }
@@ -90,8 +96,10 @@ class AggDatasetOuter extends AggDataset {
       this.ncoord = stoker.countTokens();
     }
 
-    this.isStringValued = isString; // LOOK ??
+    coordDataType = aggCoordDataType;
     this.coordValue = coordValueS;
+    // not dealing with scan
+    this.coordUdunit = "";
     this.coordValueDate = null; // LOOK why isnt this set?
   }
 
@@ -115,13 +123,21 @@ private String extractCoordNameFromFilename(String loc) {
     // default is that the coordinates are just the filenames
     // this can be overriden by an explicit declaration, which will replace the variable after ther agg is processed in
     // NcMLReader
+    DataType aggCoordDataType = DataType.DOUBLE;
+    String coordUdunit = "";
     if ((aggregationOuter.type == Type.joinNew) || (aggregationOuter.type == Type.joinExistingOne)
         || (aggregationOuter.type == Type.forecastModelRunCollection)) {
       coordValueS = extractCoordNameFromFilename(this.getLocation());
-      this.isStringValued = true;
-    } else {
-      this.isStringValued = false; // LOOK ??
+      if (aggregationOuter.numericTimeSettings != null) {
+        String[] settings = aggregationOuter.numericTimeSettings.split(" ", 2);
+        aggCoordDataType = DataType.getType(settings[0]);
+        coordUdunit = settings[1];
+      } else {
+        aggCoordDataType = DataType.STRING;
+      }
     }
+    this.coordDataType = aggCoordDataType;
+    this.coordUdunit = coordUdunit;
 
     if (null != aggregationOuter.dateFormatMark) {
       String filename = cd.getName(); // LOOK operates on name, not path

cdm/core/src/main/java/ucar/nc2/internal/ncml/Aggregation.java

@@ -1,6 +1,8 @@
 /*
- * Copyright (c) 1998-2020 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
+ * See LICENSE.txt for license information.
  */
+
 package ucar.nc2.internal.ncml;
 
 import org.jdom2.Element;
@@ -95,6 +97,7 @@ else if (mode.equalsIgnoreCase("first"))
 
   // experimental
   protected String dateFormatMark;
+  protected String numericTimeSettings;
   // protected EnumSet<NetcdfDataset.Enhance> enhance = null; // default no enhancement
   protected boolean isDate;
   protected DateFormatter dateFormatter = new DateFormatter();
@@ -153,13 +156,17 @@ public void addDataset(AggDataset nested) {
    * @param subdirs equals "false" if should not descend into subdirectories
    * @param olderThan files must be older than this time (now - lastModified >= olderThan); must be a time unit, may ne
    *        bull
+   * @param numericTimeSettings numeric time settings (data type and udunits compatible string,
+   *        e.g. "float seconds since 1985-10-18T12:31:00", may be null)
    */
   public void addDatasetScan(Element crawlableDatasetElement, String dirName, String suffix, String regexpPatternString,
-      String dateFormatMark, Set<NetcdfDataset.Enhance> enhanceMode, String subdirs, String olderThan) {
+      String dateFormatMark, Set<NetcdfDataset.Enhance> enhanceMode, String subdirs, String olderThan,
+      String numericTimeSettings) {
 
     datasetManager.addDirectoryScan(dirName, suffix, regexpPatternString, subdirs, olderThan, enhanceMode);
 
     this.dateFormatMark = dateFormatMark;
+    this.numericTimeSettings = numericTimeSettings;
     if (dateFormatMark != null) {
       isDate = true;
       if (type == Type.joinExisting)

cdm/core/src/main/java/ucar/nc2/internal/ncml/AggregationExisting.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -76,7 +76,13 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
       }
 
     } else {
-      coordCacheVar = new CoordValueVar(dimName, DataType.STRING, "");
+      DataType coordDataType = DataType.STRING;
+      String coordUnits = "";
+      if (typicalDataset instanceof AggDatasetOuter) {
+        coordDataType = ((AggDatasetOuter) typicalDataset).coordDataType;
+        coordUnits = ((AggDatasetOuter) typicalDataset).coordUdunit;
+      }
+      coordCacheVar = new CoordValueVar(dimName, coordDataType, coordUnits);
     }
     if (coordCacheVar != null) {
       cacheList.add(coordCacheVar); // coordinate variable is always cached
@@ -134,8 +140,14 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
     if (type == Type.joinExistingOne) {
       // replace aggregation coordinate variable
       joinAggCoordOpt.ifPresent(joinAgg -> rootGroup.removeVariable(joinAgg.shortName));
+      DataType coordDataType = DataType.STRING;
+      String coordUnits = "";
+      if (typicalDataset instanceof AggDatasetOuter) {
+        coordDataType = ((AggDatasetOuter) typicalDataset).coordDataType;
+        coordUnits = ((AggDatasetOuter) typicalDataset).coordUdunit;
+      }
 
-      joinAggCoord = VariableDS.builder().setName(dimName).setDataType(DataType.STRING).setParentGroupBuilder(rootGroup)
+      joinAggCoord = VariableDS.builder().setName(dimName).setDataType(coordDataType).setParentGroupBuilder(rootGroup)
           .setDimensionsByName(dimName);
       joinAggCoord.setProxyReader(this);
       rootGroup.addVariable(joinAggCoord);
@@ -144,6 +156,9 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
       joinAggCoord.addAttribute(new Attribute(_Coordinate.AxisType, "Time"));
       joinAggCoord.addAttribute(new Attribute(CDM.LONG_NAME, "time coordinate"));
       joinAggCoord.addAttribute(new Attribute(CF.STANDARD_NAME, "time"));
+      if (coordUnits != null && !coordUnits.equals("")) {
+        joinAggCoord.addAttribute(new Attribute(CF.UNITS, coordUnits));
+      }
     }
 
     if (timeUnitsChange && joinAggCoord != null) {

cdm/core/src/main/java/ucar/nc2/internal/ncml/AggregationNew.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -149,7 +149,7 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
   private DataType getCoordinateType() {
     List<AggDataset> nestedDatasets = getDatasets();
     AggDatasetOuter first = (AggDatasetOuter) nestedDatasets.get(0);
-    return first.isStringValued ? DataType.STRING : DataType.DOUBLE;
+    return first.coordDataType;
   }
 
 }

cdm/core/src/main/java/ucar/nc2/internal/ncml/NcmlReader.java

@@ -1,7 +1,8 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
+
 package ucar.nc2.internal.ncml;
 
 import java.io.FileNotFoundException;
@@ -1526,6 +1527,7 @@ private Aggregation readAgg(Element aggElem, String ncmlLocation, NetcdfDataset.
       String olderS = scanElem.getAttributeValue("olderThan");
 
       String dateFormatMark = scanElem.getAttributeValue("dateFormatMark");
+      String numericTimeSettings = scanElem.getAttributeValue("numericTimeSettings");
       Set<NetcdfDataset.Enhance> enhanceMode = NetcdfDataset.parseEnhanceMode(scanElem.getAttributeValue("enhance"));
 
       // possible relative location
@@ -1534,7 +1536,7 @@ private Aggregation readAgg(Element aggElem, String ncmlLocation, NetcdfDataset.
       // can embed a full-blown crawlableDatasetImpl element
       Element cdElement = scanElem.getChild("crawlableDatasetImpl", ncNS); // ok if null
       agg.addDatasetScan(cdElement, dirLocation, suffix, regexpPatternString, dateFormatMark, enhanceMode, subdirs,
-          olderS);
+          olderS, numericTimeSettings);
 
       if ((cancelTask != null) && cancelTask.isCancel()) {
         return agg;

cdm/core/src/main/java/ucar/nc2/ncml/Aggregation.java

@@ -2,6 +2,7 @@
  * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE.txt for license information.
  */
+
 package ucar.nc2.ncml;
 
 import org.jdom2.Element;
@@ -153,6 +154,7 @@ else if (mode.equalsIgnoreCase("first"))
 
   // experimental
   protected String dateFormatMark;
+  protected String numericTimeSettings;
   // protected EnumSet<NetcdfDataset.Enhance> enhance = null; // default no enhancement
   protected boolean isDate;
   protected DateFormatter dateFormatter = new DateFormatter();
@@ -199,6 +201,7 @@ public void addDataset(Dataset nested) {
     explicitDatasets.add(nested);
   }
 
+
   /**
    * Add a dataset scan
    *
@@ -214,10 +217,33 @@ public void addDataset(Dataset nested) {
    */
   public void addDatasetScan(Element crawlableDatasetElement, String dirName, String suffix, String regexpPatternString,
       String dateFormatMark, Set<NetcdfDataset.Enhance> enhanceMode, String subdirs, String olderThan) {
+    addDatasetScan(crawlableDatasetElement, dirName, suffix, regexpPatternString, dateFormatMark, enhanceMode, subdirs,
+        olderThan, null);
+  }
+
+  /**
+   * Add a dataset scan
+   *
+   * @param crawlableDatasetElement defines a CrawlableDataset, or null
+   * @param dirName scan this directory
+   * @param suffix filter on this suffix (may be null)
+   * @param regexpPatternString include if full name matches this regular expression (may be null)
+   * @param dateFormatMark create dates from the filename (may be null)
+   * @param enhanceMode how should files be enhanced
+   * @param subdirs equals "false" if should not descend into subdirectories
+   * @param olderThan files must be older than this time (now - lastModified >= olderThan); must be a time unit, may ne
+   *        bull
+   * @param numericTimeSettings numeric time settings (data type and udunits compatible string,
+   *        e.g. "float seconds since 1985-10-18T12:31:00", may be null)
+   */
+  public void addDatasetScan(Element crawlableDatasetElement, String dirName, String suffix, String regexpPatternString,
+      String dateFormatMark, Set<NetcdfDataset.Enhance> enhanceMode, String subdirs, String olderThan,
+      String numericTimeSettings) {
 
     datasetManager.addDirectoryScan(dirName, suffix, regexpPatternString, subdirs, olderThan, enhanceMode);
 
     this.dateFormatMark = dateFormatMark;
+    this.numericTimeSettings = numericTimeSettings;
     if (dateFormatMark != null) {
       isDate = true;
       if (type == Type.joinExisting)

cdm/core/src/main/java/ucar/nc2/ncml/AggregationExisting.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -71,7 +71,13 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
       }
 
     } else {
-      coordCacheVar = new CoordValueVar(dimName, DataType.STRING, "");
+      DataType coordDataType = DataType.STRING;
+      String coordUnits = null;
+      if (typicalDataset instanceof AggregationOuterDimension.DatasetOuterDimension) {
+        coordDataType = ((AggregationOuterDimension.DatasetOuterDimension) typicalDataset).coordDataType;
+        coordUnits = ((AggregationOuterDimension.DatasetOuterDimension) typicalDataset).coordUdunit;
+      }
+      coordCacheVar = new CoordValueVar(dimName, coordDataType, coordUnits);
     }
     if (coordCacheVar != null) {
       cacheList.add(coordCacheVar); // coordinate variable is always cached
@@ -128,15 +134,24 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
         // replace aggregation coordinate variable
         ncDataset.getRootGroup().removeVariable(joinAggCoord.getShortName());
       }
-
-      joinAggCoord = new VariableDS(ncDataset, null, null, dimName, DataType.STRING, dimName, null, null);
+      DataType coordDataType = DataType.STRING;
+      String coordUnits = null;
+      if (typicalDataset instanceof AggregationOuterDimension.DatasetOuterDimension) {
+        coordDataType = ((AggregationOuterDimension.DatasetOuterDimension) typicalDataset).coordDataType;
+        coordUnits = ((AggregationOuterDimension.DatasetOuterDimension) typicalDataset).coordUdunit;
+      }
+      coordCacheVar = new CoordValueVar(dimName, coordDataType, coordUnits);
+      joinAggCoord = new VariableDS(ncDataset, null, null, dimName, coordDataType, dimName, coordUnits, null);
       joinAggCoord.setProxyReader(this);
       ncDataset.getRootGroup().addVariable(joinAggCoord);
       aggVars.add(joinAggCoord);
 
       joinAggCoord.addAttribute(new ucar.nc2.Attribute(_Coordinate.AxisType, "Time"));
       joinAggCoord.addAttribute(new Attribute(CDM.LONG_NAME, "time coordinate"));
       joinAggCoord.addAttribute(new ucar.nc2.Attribute(CF.STANDARD_NAME, "time"));
+      if (coordUnits != null && !coordUnits.equals("")) {
+        joinAggCoord.addAttribute(new Attribute(CF.UNITS, coordUnits));
+      }
     }
 
     if (timeUnitsChange && joinAggCoord != null) {

cdm/core/src/main/java/ucar/nc2/ncml/AggregationNew.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -134,7 +134,7 @@ protected void buildNetcdfDataset(CancelTask cancelTask) throws IOException {
   private DataType getCoordinateType() {
     List<Dataset> nestedDatasets = getDatasets();
     DatasetOuterDimension first = (DatasetOuterDimension) nestedDatasets.get(0);
-    return first.isStringValued ? DataType.STRING : DataType.DOUBLE;
+    return first.coordDataType;
   }
 
 }