WIP: ZARR: add a prototype read implementation of the geo/proj attribute conventions... [ci skip]

autotest/gdrivers/data/zarr/byte_geo_proj_prototype.zarr/X/zarr.json

@@ -0,0 +1,36 @@
+{
+  "zarr_format":3,
+  "node_type":"array",
+  "shape":[
+    20
+  ],
+  "data_type":"float64",
+  "chunk_grid":{
+    "name":"regular",
+    "configuration":{
+      "chunk_shape":[
+        20
+      ]
+    }
+  },
+  "chunk_key_encoding":{
+    "name":"default",
+    "configuration":{
+      "separator":"\/"
+    }
+  },
+  "fill_value":"NaN",
+  "codecs":[
+    {
+      "name":"bytes",
+      "configuration":{
+        "endian":"little"
+      }
+    }
+  ],
+  "attributes":{
+  },
+  "dimension_names":[
+    "X"
+  ]
+}

autotest/gdrivers/data/zarr/byte_geo_proj_prototype.zarr/Y/zarr.json

@@ -0,0 +1,36 @@
+{
+  "zarr_format":3,
+  "node_type":"array",
+  "shape":[
+    20
+  ],
+  "data_type":"float64",
+  "chunk_grid":{
+    "name":"regular",
+    "configuration":{
+      "chunk_shape":[
+        20
+      ]
+    }
+  },
+  "chunk_key_encoding":{
+    "name":"default",
+    "configuration":{
+      "separator":"\/"
+    }
+  },
+  "fill_value":"NaN",
+  "codecs":[
+    {
+      "name":"bytes",
+      "configuration":{
+        "endian":"little"
+      }
+    }
+  ],
+  "attributes":{
+  },
+  "dimension_names":[
+    "Y"
+  ]
+}

autotest/gdrivers/data/zarr/byte_geo_proj_prototype.zarr/byte_geo_proj/c/0/0

@@ -0,0 +1 @@
+k{�s������k�k��k{s��s�k{�s�s�k{{c�{���c�s���{s�k�s�{k��ssksk��{{s��{s{s{ks�ks�s�������sss{�{�{�kk��{�����s�{k�s��c{s���kŭ����c�{s���c�{��{s�{�s�{�{ks�sksc{c�ck{s�s{�s��{{�csc{�ssk��c�cs{k�ksks{�{k{�����{c�{k�cs{��{k{{{k{{{k�{{ssZk�kkkkc�{s��c{{k{ck��ksskc�k�����k{ccsc�c�s�{c�{���k�ZkskZc{sss{{�s�c����{kkks�csccks�sZ{s�����s�ZcsZcckc�ck������{�cs{Jsc{������c���΄k�{�������{k{k{����������s�kkkkksck

autotest/gdrivers/data/zarr/byte_geo_proj_prototype.zarr/byte_geo_proj/zarr.json

@@ -0,0 +1,54 @@
+{
+  "zarr_format":3,
+  "node_type":"array",
+  "shape":[
+    20,
+    20
+  ],
+  "data_type":"uint8",
+  "chunk_grid":{
+    "name":"regular",
+    "configuration":{
+      "chunk_shape":[
+        20,
+        20
+      ]
+    }
+  },
+  "chunk_key_encoding":{
+    "name":"default",
+    "configuration":{
+      "separator":"\/"
+    }
+  },
+  "fill_value":0,
+  "codecs":[
+    {
+      "name":"bytes",
+      "configuration":{
+        "endian":"little"
+      }
+    }
+  ],
+  "attributes":{
+    "zarr_conventions_version": "0.1.0",
+    "zarr_conventions":
+    {
+        "f17cb550-5864-4468-aeb7-f3180cfb622f": {
+            "version": "0.1",
+            "name": "geo/proj",
+            "description": "",
+            "schema": "http://example.com/geo.proj.schema.json",
+            "configuration": {
+                "code": "EPSG:26711",
+                "spatial_dimensions": ["Y", "X"],
+                "transform": [60, 0, 440720, 0, 60, 3750120]
+            }
+        }
+    }
+  },
+  "dimension_names":[
+    "Y",
+    "X"
+  ]
+}

autotest/gdrivers/data/zarr/byte_geo_proj_prototype.zarr/zarr.json

@@ -0,0 +1,5 @@
+{
+    "zarr_format": 3,
+    "node_type": "group",
+    "attributes": {}
+}

autotest/gdrivers/zarr_driver.py

@@ -5869,3 +5869,16 @@ def test_zarr_read_zarr_with_stac_proj_wkt2():
 def test_zarr_identify_file_extensions(file_path):
     ds = gdal.Open(file_path)
     ds.GetRasterBand(1).Checksum()
+
+
+###############################################################################
+#
+
+
+@gdaltest.enable_exceptions()
+def test_zarr_read_zarr_geo_proj_prototype():
+
+    ds = gdal.Open("data/zarr/byte_geo_proj_prototype.zarr")
+    assert ds.GetSpatialRef().GetAuthorityCode(None) == "26711"
+    assert ds.GetSpatialRef().GetDataAxisToSRSAxisMapping() == [1, 2]
+    assert ds.GetGeoTransform() == (440720.0, 60.0, 0.0, 3751320.0, 0.0, -60.0)

frmts/zarr/zarr_array.cpp

@@ -2816,7 +2816,163 @@ void ZarrArray::ParseSpecialAttributes(
         // 1-dimensional array with the values.
     }
 
-    if (poSRS)
+    bool bAxisAssigned = false;
+    const auto oZarrConventions = oAttributes["zarr_conventions"];
+    if (oZarrConventions.GetType() == CPLJSONObject::Type::Object)
+    {
+        const auto oGeoProj =
+            oZarrConventions["f17cb550-5864-4468-aeb7-f3180cfb622f"];
+        if (oGeoProj.GetType() == CPLJSONObject::Type::Object)
+        {
+            // Cf https://github.com/EOPF-Explorer/data-model/tree/main/attributes/geo/proj
+
+            const auto osVersion = oGeoProj["version"];
+            // TODO: implement SemVer
+            if (osVersion.ToString() != "0.1.0")
+                CPLDebug(
+                    "ZARR",
+                    "geo/proj version unhandled by this implementation: %s",
+                    osVersion.ToString().c_str());
+
+            const auto oConfiguration = oGeoProj["configuration"];
+            if (oConfiguration.GetType() == CPLJSONObject::Type::Object)
+            {
+                const auto oCode = oConfiguration["code"];
+                if (oCode.GetType() == CPLJSONObject::Type::String)
+                {
+                    poSRS = std::make_shared<OGRSpatialReference>();
+                    poSRS->SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
+                    if (poSRS->SetFromUserInput(
+                            oCode.ToString().c_str(),
+                            OGRSpatialReference::
+                                SET_FROM_USER_INPUT_LIMITATIONS_get()) !=
+                        OGRERR_NONE)
+                    {
+                        poSRS.reset();
+                    }
+                }
+                else
+                {
+                    const auto oWKT2 = oConfiguration["wkt2"];
+                    if (oWKT2.GetType() == CPLJSONObject::Type::String)
+                    {
+                        poSRS = std::make_shared<OGRSpatialReference>();
+                        poSRS->SetAxisMappingStrategy(
+                            OAMS_TRADITIONAL_GIS_ORDER);
+                        if (poSRS->importFromWkt(oWKT2.ToString().c_str()) !=
+                            OGRERR_NONE)
+                        {
+                            poSRS.reset();
+                        }
+                    }
+                    else
+                    {
+                        const auto oPROJJSON = oConfiguration["projjson"];
+                        if (oPROJJSON.GetType() == CPLJSONObject::Type::Object)
+                        {
+                            poSRS = std::make_shared<OGRSpatialReference>();
+                            poSRS->SetAxisMappingStrategy(
+                                OAMS_TRADITIONAL_GIS_ORDER);
+                            if (poSRS->SetFromUserInput(
+                                    oPROJJSON.ToString().c_str(),
+                                    OGRSpatialReference::
+                                        SET_FROM_USER_INPUT_LIMITATIONS_get()) !=
+                                OGRERR_NONE)
+                            {
+                                poSRS.reset();
+                            }
+                        }
+                    }
+                }
+
+                if (poSRS)
+                {
+                    const auto oSpatialDimensions =
+                        oConfiguration["spatial_dimensions"];
+                    int iDimName1 = 0;
+                    int iDimName2 = 0;
+                    if (oSpatialDimensions.GetType() ==
+                            CPLJSONObject::Type::Array &&
+                        oSpatialDimensions.ToArray().Size() == 2)
+                    {
+                        const auto osName1 =
+                            oSpatialDimensions.ToArray()[0].ToString();
+                        const auto osName2 =
+                            oSpatialDimensions.ToArray()[1].ToString();
+                        int iDim = 1;
+                        for (const auto &poDim : GetDimensions())
+                        {
+                            if (poDim->GetName() == osName1)
+                                iDimName1 = iDim;
+                            else if (poDim->GetName() == osName2)
+                                iDimName2 = iDim;
+                            ++iDim;
+                        }
+                        if (iDimName1 == 0)
+                        {
+                            CPLError(CE_Warning, CPLE_AppDefined,
+                                     "spatial_dimensions[0] = %s is a unknown "
+                                     "Zarr dimension",
+                                     osName1.c_str());
+                        }
+                        if (iDimName2 == 0)
+                        {
+                            CPLError(CE_Warning, CPLE_AppDefined,
+                                     "spatial_dimensions[1] = %s is a unknown "
+                                     "Zarr dimension",
+                                     osName2.c_str());
+                        }
+                    }
+                    else
+                    {
+                        int iDim = 1;
+                        for (const auto &poDim : GetDimensions())
+                        {
+                            if (poDim->GetName() == "y" ||
+                                poDim->GetName() == "Y" ||
+                                poDim->GetName() == "lat" ||
+                                poDim->GetName() == "latitude" ||
+                                poDim->GetName() == "northing" ||
+                                poDim->GetName() == "row")
+                            {
+                                iDimName1 = iDim;
+                            }
+                            else if (poDim->GetName() == "x" ||
+                                     poDim->GetName() == "X" ||
+                                     poDim->GetName() == "lon" ||
+                                     poDim->GetName() == "longitude" ||
+                                     poDim->GetName() == "easting" ||
+                                     poDim->GetName() == "col")
+                            {
+                                iDimName2 = iDim;
+                            }
+                            ++iDim;
+                        }
+                    }
+                    if (iDimName1 > 0 && iDimName2 > 0)
+                    {
+                        bAxisAssigned = true;
+                        const int iDimY = std::min(iDimName1, iDimName2);
+                        const int iDimX = std::max(iDimName1, iDimName2);
+                        const auto &oMapping =
+                            poSRS->GetDataAxisToSRSAxisMapping();
+                        if (oMapping == std::vector<int>{2, 1} ||
+                            oMapping == std::vector<int>{2, 1, 3})
+                            poSRS->SetDataAxisToSRSAxisMapping({iDimY, iDimX});
+                        else if (oMapping == std::vector<int>{1, 2} ||
+                                 oMapping == std::vector<int>{1, 2, 3})
+                            poSRS->SetDataAxisToSRSAxisMapping({iDimX, iDimY});
+
+                        SetSRS(poSRS);
+                    }
+                }
+
+                // TODO deal with "bbox"? and "transform"
+            }
+        }
+    }
+
+    if (poSRS && !bAxisAssigned)
     {
         int iDimX = 0;
         int iDimY = 0;