From c6f7fa8fb767015542724a7fd719ab7eca160d8b Mon Sep 17 00:00:00 2001
From: Alex Cunningham <alexgcunningham@gmail.com>
Date: Tue, 18 Sep 2012 17:48:20 +0000
Subject: [PATCH] Check that P is non-empty before drawing covariance ellipses

---
 matlab/+gtsam/plotPoint2.m | 2 +-
 matlab/+gtsam/plotPose2.m  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/matlab/+gtsam/plotPoint2.m b/matlab/+gtsam/plotPoint2.m
index 55e476118..cd066951d 100644
--- a/matlab/+gtsam/plotPoint2.m
+++ b/matlab/+gtsam/plotPoint2.m
@@ -5,6 +5,6 @@ if size(color,2)==1
 else
     plot(p.x,p.y,color);
 end
-if exist('P', 'var')
+if exist('P', 'var') && (~isempty(P))
     gtsam.covarianceEllipse([p.x;p.y],P,color(1));
 end
\ No newline at end of file
diff --git a/matlab/+gtsam/plotPose2.m b/matlab/+gtsam/plotPose2.m
index 799bad48e..7156f9b60 100644
--- a/matlab/+gtsam/plotPose2.m
+++ b/matlab/+gtsam/plotPose2.m
@@ -6,7 +6,7 @@ plot(pose.x,pose.y,[color '*']);
 c = cos(pose.theta);
 s = sin(pose.theta);
 quiver(pose.x,pose.y,c,s,axisLength,color);
-if nargin>2
+if nargin>2 && (~isempty(P))
     pPp = P(1:2,1:2); % covariance matrix in pose coordinate frame    
     gRp = [c -s;s c]; % rotation from pose to global
     gtsam.covarianceEllipse([pose.x;pose.y],gRp*pPp*gRp',color);