Write X/Y as degrees in geographic dfsu files

CHANGELOG.md

@@ -65,5 +65,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   it, instead of raising `IndexError`. The native library ignores the key.
 - `DfsFile.WriteItemTimeStepNext` reports data shorter than the item with its
   size, instead of raising `AttributeError`.
+- `DfsuBuilder` writes the `X-coord` and `Y-coord` static items of a file with
+  a geographic projection, such as `LONG/LAT`, as `eumILatLong` in degrees.
+  They were `eumIGeographicalCoordinate` in metres whatever the projection.
+  Files with a projected coordinate system are unchanged
+  ([#47](https://github.com/DHI/mikecore-python/issues/47)).
 
 [Unreleased]: https://github.com/DHI/mikecore-python/compare/v0.3.a1...HEAD

mikecore/DfsuBuilder.py

@@ -14,6 +14,7 @@
     DfsuUtil,
 )
 from mikecore.eum import eumUnit, eumQuantity, eumItem
+from mikecore.Projections import MapProjection
 
 
 # / <summary>
@@ -703,11 +704,10 @@ def CreateDfsu(self, dfsBuilder, elementType, nodesPerElmt, connectivityArray):
         nodes, connectivity = self.__NodesAndElements()
         intCode = eumQuantity(eumItem.eumIIntegerCode, eumUnit.eumUintCode)
         xyQuantity = eumQuantity(eumItem.eumIGeographicalCoordinate, eumUnit.eumUmeter)
-
-        # TODO: reenable:
-        # if (MapProjection.IsValid(self.__dfsProjection.WKTString)):
-        #    if (MapProjection.IsGeographical(self.__dfsProjection.WKTString)):
-        #        xyQuantity = eumQuantity(eumItem.eumILatLong, eumUnit.eumUdegree)
+        if self.__dfsProjection is not None:
+            wkt = self.__dfsProjection.WKTString
+            if MapProjection.IsValid(wkt) and MapProjection.IsGeographical(wkt):
+                xyQuantity = eumQuantity(eumItem.eumILatLong, eumUnit.eumUdegree)
 
         # Node id
         nodeIdItem = dfsBuilder.AddCreateStaticItem("Node id", intCode, self.__nodeIds)

tests/test_dfsu_builder.py

@@ -5,6 +5,7 @@
 from numpy.testing import assert_array_equal
 
 from mikecore.DfsFactory import DfsFactory
+from mikecore.DfsFileFactory import DfsFileFactory
 from mikecore.DfsuBuilder import DfsuBuilder
 from mikecore.DfsuFile import DfsuFile, DfsuFileType
 from mikecore.eum import eumItem, eumQuantity, eumUnit
@@ -102,6 +103,31 @@ def test_z_unit_is_written(tmp_path):
     dfsu.Close()
 
 
+@pytest.mark.parametrize(
+    "projection, xyQuantity",
+    [
+        ("LONG/LAT", (eumItem.eumILatLong, eumUnit.eumUdegree)),
+        ("UTM-33", (eumItem.eumIGeographicalCoordinate, eumUnit.eumUmeter)),
+        ("NON-UTM", (eumItem.eumIGeographicalCoordinate, eumUnit.eumUmeter)),
+    ],
+)
+def test_xy_quantity_follows_projection(tmp_path, projection, xyQuantity):
+    filename = str(tmp_path / "xyquantity.dfsu")
+    builder = _builder()
+    builder.SetProjection(DfsFactory().CreateProjection(projection))
+    builder.SetNodes(X, Y, Z, CODE)
+    builder.SetElements(ELEMENTS)
+    builder.CreateFile(filename).Close()
+
+    dfs = DfsFileFactory.DfsGenericOpen(filename)
+    dfs.ReadStaticItemNext()  # Node id
+    for name in ["X-coord", "Y-coord"]:
+        staticItem = dfs.ReadStaticItemNext()
+        assert name == staticItem.Name
+        assert xyQuantity == (staticItem.Quantity.Item, staticItem.Quantity.Unit)
+    dfs.Close()
+
+
 def test_z_unit_must_be_meter_or_feet():
     builder = _builder()