Merge pull request #4102 from QRemy/fix_resample

Fix weights in resample

gammapy/maps/core.py

@@ -631,10 +631,11 @@ def resample(self, geom, weights=None, preserve_counts=True):
         coords = self.geom.get_coord()
         idx = geom.coord_to_idx(coords)
 
-        resampled = self.from_geom(geom=geom)
+        weights = 1 if weights is None else weights
 
+        resampled = self.from_geom(geom=geom)
         resampled._resample_by_idx(
-            idx, weights=self.data, preserve_counts=preserve_counts
+            idx, weights=self.data * weights, preserve_counts=preserve_counts
         )
         return resampled
 

gammapy/maps/tests/test_core.py

@@ -507,6 +507,17 @@ def test_resample_wcs_Wcs():
             rtol=1e-3,
         )
 
+def test_resample_weights():
+    npix1 = 3
+    geom1 = WcsGeom.create(npix=npix1, frame="icrs")
+    map1 = Map.from_geom(geom1, data=np.eye(npix1))
+
+    geom2 = WcsGeom.create(
+        skydir=SkyCoord(0.0, 0.0, unit=u.deg), binsz=0.5, npix=7, frame="galactic"
+    )
+
+    map2 = map1.resample(geom2, weights=np.zeros(npix1), preserve_counts=False)
+    assert np.sum(map2.data) == 0.
 
 def test_resample_downsample_wcs():
     geom_fine = WcsGeom.create(npix=(15, 15), frame="icrs")