From a005273724ac302e13a816e049b66d61bf65ca84 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Fri, 22 Sep 2017 09:33:03 +0100
Subject: [PATCH] Quiet a warning loading some ground-nets

---
 src/Airports/dynamicloader.cxx | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Airports/dynamicloader.cxx b/src/Airports/dynamicloader.cxx
index 03e27e069..d12e5addb 100644
--- a/src/Airports/dynamicloader.cxx
+++ b/src/Airports/dynamicloader.cxx
@@ -128,7 +128,11 @@ void FGGroundNetXMLLoader::startParking(const XMLAttributes &atts)
     else if (attname == "pushBackRoute") {
       const string attrVal = atts.getValue(i);
       try {
-        pushBackRoute = simgear::strutils::readNonNegativeInt<int>(attrVal);
+          if (attrVal == "None") {
+              pushBackRoute = -2;
+          } else {
+              pushBackRoute = simgear::strutils::readNonNegativeInt<int>(attrVal);
+          }
       } catch (const sg_exception& e) {
         SG_LOG(SG_NAVAID, SG_DEV_WARN,
                getPath() << ":" << getLine() << ": " <<