check for coordinates before running hyperbolic routing

refs: #4252

Change-Id: I04a4278443f02eef29666800fb3cd22e53a5ca28
diff --git a/ndn_utils/topologies/default-topology.conf b/ndn_utils/topologies/default-topology.conf
index 9452122..302e4a8 100644
--- a/ndn_utils/topologies/default-topology.conf
+++ b/ndn_utils/topologies/default-topology.conf
@@ -1,8 +1,8 @@
 [nodes]
-a: _
-b: _
-c: _
-d: _
+a: _ radius=0.5 angle=2.64159265359
+b: _ radius=0.6 angle=3.64159265359
+c: _ radius=1 angle=1.57079632679
+d: _ radius=1 angle=4.71238898038
 [links]
 a:b delay=10ms
 a:c delay=10ms