diff --git a/src/db/db/dbRegionUtils.cc b/src/db/db/dbRegionUtils.cc
index f1e9e9c17..3214fa747 100644
--- a/src/db/db/dbRegionUtils.cc
+++ b/src/db/db/dbRegionUtils.cc
@@ -76,7 +76,7 @@ static inline bool shields (const db::EdgePair &ep, const db::Edge &q)
   std::pair<bool, db::Point> ip2 = pe2.intersect_point (q);
 
   if (ip1.first && ip2.first) {
-    return ip1.second != ip2.second || (ip1.second != q.p1 () && ip2.second != q.p2 ());
+    return ip1.second != ip2.second || (pe1.side_of (q.p1 ()) != 0 && pe2.side_of (q.p2 ()) != 0);
   } else {
     return false;
   }
diff --git a/src/drc/unit_tests/drcSimpleTests.cc b/src/drc/unit_tests/drcSimpleTests.cc
index b0e38fe9f..dad8bbc50 100644
--- a/src/drc/unit_tests/drcSimpleTests.cc
+++ b/src/drc/unit_tests/drcSimpleTests.cc
@@ -674,3 +674,43 @@ TEST(14_SwitchingTargets)
 
   db::compare_layouts (_this, layout2, au2, db::NoNormalization);
 }
+
+TEST(15_issue548)
+{
+  std::string rs = tl::testsrc ();
+  rs += "/testdata/drc/drcSimpleTests_15.drc";
+
+  std::string input = tl::testsrc ();
+  input += "/testdata/drc/drcSimpleTests_15.gds";
+
+  std::string au = tl::testsrc ();
+  au += "/testdata/drc/drcSimpleTests_au15.gds";
+
+  std::string output = this->tmp_file ("tmp.gds");
+
+  {
+    //  Set some variables
+    lym::Macro config;
+    config.set_text (tl::sprintf (
+        "$drc_test_source = '%s'\n"
+        "$drc_test_target = '%s'\n"
+      , input, output)
+    );
+    config.set_interpreter (lym::Macro::Ruby);
+    EXPECT_EQ (config.run (), 0);
+  }
+
+  lym::Macro drc;
+  drc.load_from (rs);
+  EXPECT_EQ (drc.run (), 0);
+
+  db::Layout layout;
+
+  {
+    tl::InputStream stream (output);
+    db::Reader reader (stream);
+    reader.read (layout);
+  }
+
+  db::compare_layouts (_this, layout, au, db::NoNormalization);
+}
diff --git a/testdata/drc/drcSimpleTests_15.drc b/testdata/drc/drcSimpleTests_15.drc
new file mode 100644
index 000000000..722252c68
--- /dev/null
+++ b/testdata/drc/drcSimpleTests_15.drc
@@ -0,0 +1,10 @@
+
+source($drc_test_source, "TOP")
+target($drc_test_target)
+
+# various shielding configurations
+
+l1 = input(1,0)
+l1.output(1, 0)
+l1.space(0.21.um, euclidian).output(10, 0)
+
diff --git a/testdata/drc/drcSimpleTests_15.gds b/testdata/drc/drcSimpleTests_15.gds
new file mode 100644
index 000000000..d25c39fa5
Binary files /dev/null and b/testdata/drc/drcSimpleTests_15.gds differ
diff --git a/testdata/drc/drcSimpleTests_au15.gds b/testdata/drc/drcSimpleTests_au15.gds
new file mode 100644
index 000000000..dd81433d9
Binary files /dev/null and b/testdata/drc/drcSimpleTests_au15.gds differ