Merge d007d6d into af164ad

astrofrog · May 24, 2016 · 1f38253 · 1f38253
2 parents af164ad + d007d6d
commit 1f38253
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Showing 2 changed files with 10 additions and 3 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -1,7 +1,8 @@
 0.8 (unreleased)
 ----------------
 
-- No changes yet.
+- Fix a bug that caused WCSAxes to crash when trying to transform arrays with
+  zero coordinates.
 
 0.7 (2016-05-06)
 ----------------

diff --git a/wcsaxes/transforms.py b/wcsaxes/transforms.py
@@ -95,7 +95,10 @@ def transform(self, world):
         if world.shape[1] != self.wcs.wcs.naxis:
             raise ValueError("Second dimension of input values should match number of WCS coordinates")
 
-        pixel = self.wcs.wcs_world2pix(world, 1) - 1
+        if world.shape[0] == 0:
+            pixel = np.zeros((0, 2))
+        else:
+            pixel = self.wcs.wcs_world2pix(world, 1) - 1
 
         if self.slice is None:
             return pixel
@@ -162,7 +165,10 @@ def transform(self, pixel):
 
         pixel_full += 1
 
-        world = self.wcs.wcs_pix2world(pixel_full, 1)
+        if pixel_full.shape[0] == 0:
+            world = np.zeros((0, 2))
+        else:
+            world = self.wcs.wcs_pix2world(pixel_full, 1)
 
         # At the moment, one has to manually check that the transformation
         # round-trips, otherwise it should be considered invalid.