From 9a80c2d38b11f4113ff56e6a858625ce71d84c6e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Laura=20Kl=C3=BCnder?= <laura@codingcatgirl.de>
Date: Mon, 15 Jan 2018 19:12:07 +0100
Subject: [PATCH] dont crash if zero vertices are to build in
 _build_vertex_values

---
 src/c3nav/mapdata/render/geometry/level.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/c3nav/mapdata/render/geometry/level.py b/src/c3nav/mapdata/render/geometry/level.py
index 84282a65..6f70c8fd 100644
--- a/src/c3nav/mapdata/render/geometry/level.py
+++ b/src/c3nav/mapdata/render/geometry/level.py
@@ -253,6 +253,8 @@ class LevelGeometries:
         Interpolate vertice with known altitudes to get altitudes for the remaining ones.
         """
         vertex_values = np.empty(self.vertices.shape[:1], dtype=np.int32)
+        if not vertex_values.size:
+            return vertex_values
         vertex_value_mask = np.full(self.vertices.shape[:1], fill_value=False, dtype=np.bool)
 
         for item in items: