From f8d85a45ed314cf6cf561fbf6602c220a1da1726 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Mon, 26 Aug 2024 12:27:36 +0200
Subject: [PATCH] netCDF: honour BAND_NAMES creation option in CreateCopy()

Fixes #10646
---
 autotest/gdrivers/netcdf.py    | 26 ++++++++++++++++++++++++++
 frmts/netcdf/netcdfdataset.cpp | 25 ++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/autotest/gdrivers/netcdf.py b/autotest/gdrivers/netcdf.py
index ac9dd2c9961b..90f907ccb4e8 100755
--- a/autotest/gdrivers/netcdf.py
+++ b/autotest/gdrivers/netcdf.py
@@ -6510,6 +6510,32 @@ def test_band_names_creation_option(tmp_path):
         assert gdal.GetSubdatasetInfo(sds_names[1]).GetSubdatasetComponent() == "prate"
 
 
+@gdaltest.enable_exceptions()
+def test_band_names_creation_option_createcopy(tmp_path):
+
+    fname = tmp_path / "out.nc"
+
+    # 1 band, 2 names
+    with pytest.raises(Exception, match="but 2 names provided"):
+        src_ds = gdal.GetDriverByName("MEM").Create("", 1, 1)
+        gdal.GetDriverByName("NetCDF").CreateCopy(
+            fname, src_ds, options={"BAND_NAMES": "t2m,prate"}
+        )
+
+    # 2 bands, 2 names
+    src_ds = gdal.GetDriverByName("MEM").Create("", 1, 1, 2)
+    with gdal.GetDriverByName("NetCDF").CreateCopy(
+        fname, src_ds, options={"BAND_NAMES": "t2m,prate"}
+    ):
+        pass
+
+    with gdal.Open(fname) as ds:
+        sds_names = [sds[0] for sds in ds.GetSubDatasets()]
+
+        assert gdal.GetSubdatasetInfo(sds_names[0]).GetSubdatasetComponent() == "t2m"
+        assert gdal.GetSubdatasetInfo(sds_names[1]).GetSubdatasetComponent() == "prate"
+
+
 @gdaltest.enable_exceptions()
 def test_netcdf_create_metadata_with_equal_sign(tmp_path):
 
diff --git a/frmts/netcdf/netcdfdataset.cpp b/frmts/netcdf/netcdfdataset.cpp
index 5e5ce8d0cbe4..aa2ab535501b 100644
--- a/frmts/netcdf/netcdfdataset.cpp
+++ b/frmts/netcdf/netcdfdataset.cpp
@@ -9483,6 +9483,24 @@ netCDFDataset::CreateCopy(const char *pszFilename, GDALDataset *poSrcDS,
         }
     }
 
+    CPLStringList aosBandNames;
+    if (const char *pszBandNames =
+            CSLFetchNameValue(papszOptions, "BAND_NAMES"))
+    {
+        aosBandNames =
+            CSLTokenizeString2(pszBandNames, ",", CSLT_HONOURSTRINGS);
+
+        if (aosBandNames.Count() != nBands)
+        {
+            CPLError(CE_Failure, CPLE_OpenFailed,
+                     "Attempted to create netCDF with %d bands but %d names "
+                     "provided in BAND_NAMES.",
+                     nBands, aosBandNames.Count());
+
+            return nullptr;
+        }
+    }
+
     if (!pfnProgress(0.0, nullptr, pProgressData))
         return nullptr;
 
@@ -9692,7 +9710,12 @@ netCDFDataset::CreateCopy(const char *pszFilename, GDALDataset *poSrcDS,
         const char *pszNETCDF_VARNAME =
             poSrcBand->GetMetadataItem("NETCDF_VARNAME");
         char szBandName[NC_MAX_NAME + 1];
-        if (pszNETCDF_VARNAME)
+        if (!aosBandNames.empty())
+        {
+            snprintf(szBandName, sizeof(szBandName), "%s",
+                     aosBandNames[iBand - 1]);
+        }
+        else if (pszNETCDF_VARNAME)
         {
             if (nBands > 1 && papszExtraDimNames == nullptr)
                 snprintf(szBandName, sizeof(szBandName), "%s%d",