pcl::ConvexHull not instantiated for pcl::PointXY?

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I get a linker error:

undefined reference to pcl::ConvexHull<pcl::pointxy>::reconstruct(pcl::PointCloud<pcl::pointxy>&)

My manifest.xml includes "pcl" and "pcl_ros" listed as dependencies Should I use some other point type for computing convex hull of 2D points?

pcl::PointCloud<pcl::PointXY> rectConvexHull;  // the convex hull in ROS.

void compute2DConvexHull()
{
    if(rectConvexHull.size()>0)
        return;

    pcl::ConvexHull<pcl::PointXY> computeConvexHull;

    computeConvexHull.setInputCloud(scene2DPtr);

    computeConvexHull.setIndices(getPointIndicesBoostPtr());

    computeConvexHull.reconstruct(rectConvexHull);
}