From fe1f4ab78644d6e2018d6d73e93060fc3a88ebbf Mon Sep 17 00:00:00 2001
From: Henrik Andersson <jan@dhigroup.com>
Date: Tue, 19 Dec 2023 18:54:27 +0100
Subject: [PATCH 1/2] Avoid accidental mismatch

---
 modelskill/matching.py |  6 +++++
 tests/test_match.py    | 52 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/modelskill/matching.py b/modelskill/matching.py
index 31f8f71b5..e7a15159e 100644
--- a/modelskill/matching.py
+++ b/modelskill/matching.py
@@ -216,6 +216,12 @@ def match(
 
     assert isinstance(obs, Iterable)
 
+    if len(obs) > 1 and isinstance(mod, Iterable) and len(mod) > 1:
+        if not all(isinstance(m, (DfsuModelResult, GridModelResult)) for m in mod):
+            raise ValueError(
+                "Multiple models can only be compared if they are the the observation can be extracted, e.g. DfsuModelResult or GridModelResult"
+            )
+
     clist = [
         _single_obs_compare(
             o,
diff --git a/tests/test_match.py b/tests/test_match.py
index 38f3fc890..bc564a986 100644
--- a/tests/test_match.py
+++ b/tests/test_match.py
@@ -457,3 +457,55 @@ def test_mod_aux_items_must_be_unique():
 
     assert "wind_speed" in str(e.value)
     assert "remote" in str(e.value)
+
+
+def test_multiple_obs_not_allowed_with_non_spatial_modelresults():
+    o1 = ms.PointObservation(
+        pd.DataFrame(
+            {"wl": [1.0, 2.0]}, index=pd.date_range("2000", freq="H", periods=2)
+        ),
+        name="o1",
+        x=1,
+        y=2,
+    )
+    o2 = ms.PointObservation(
+        pd.DataFrame(
+            {"wl": [1.0, 2.0]}, index=pd.date_range("2000", freq="H", periods=2)
+        ),
+        name="o2",
+        x=2,
+        y=3,
+    )
+    m1 = ms.PointModelResult(
+        pd.DataFrame(
+            {"wl": [1.0, 2.0]}, index=pd.date_range("2000", freq="H", periods=2)
+        ),
+        name="m1",
+        x=1,
+        y=2,
+    )
+    m2 = ms.PointModelResult(
+        pd.DataFrame(
+            {"wl": [1.0, 2.0]}, index=pd.date_range("2000", freq="H", periods=2)
+        ),
+        name="m2",
+        x=2,
+        y=3,
+    )
+    m3 = ms.PointModelResult(
+        pd.DataFrame(
+            {"wl": [1.0, 2.0]}, index=pd.date_range("2000", freq="H", periods=2)
+        ),
+        name="m3",
+        x=3,
+        y=4,
+    )
+
+    # a single observation and model is ok
+    cmp = ms.match(obs=o1, mod=[m1, m2])
+    assert "m1" in cmp.mod_names
+    assert "m2" in cmp.mod_names
+
+    # but this is not allowed
+    with pytest.raises(ValueError, match="extracted"):
+        ms.match(obs=[o1, o2], mod=[m1, m2, m3])

From 55793a7e4979273ef305e74d8d3f70693257c192 Mon Sep 17 00:00:00 2001
From: Jesper Sandvig Mariegaard
 <34088801+jsmariegaard@users.noreply.github.com>
Date: Wed, 20 Dec 2023 12:21:52 +0000
Subject: [PATCH 2/2] expand error message

---
 modelskill/matching.py | 10 +++++++++-
 tests/test_match.py    |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/modelskill/matching.py b/modelskill/matching.py
index e7a15159e..fa6c32127 100644
--- a/modelskill/matching.py
+++ b/modelskill/matching.py
@@ -219,7 +219,15 @@ def match(
     if len(obs) > 1 and isinstance(mod, Iterable) and len(mod) > 1:
         if not all(isinstance(m, (DfsuModelResult, GridModelResult)) for m in mod):
             raise ValueError(
-                "Multiple models can only be compared if they are the the observation can be extracted, e.g. DfsuModelResult or GridModelResult"
+                """
+                In case of multiple observations, multiple models can _only_ 
+                be matched if they are _all_ of SpatialField type, e.g. DfsuModelResult 
+                or GridModelResult. 
+                
+                If you want match multiple point observations with multiple point model results, 
+                please match one observation at a time and then create a collection of these 
+                using modelskill.ComparerCollection(cmp_list) afterwards. The same applies to track data.
+                """
             )
 
     clist = [
diff --git a/tests/test_match.py b/tests/test_match.py
index bc564a986..359a7be2d 100644
--- a/tests/test_match.py
+++ b/tests/test_match.py
@@ -507,5 +507,5 @@ def test_multiple_obs_not_allowed_with_non_spatial_modelresults():
     assert "m2" in cmp.mod_names
 
     # but this is not allowed
-    with pytest.raises(ValueError, match="extracted"):
+    with pytest.raises(ValueError, match="SpatialField type"):
         ms.match(obs=[o1, o2], mod=[m1, m2, m3])