build heatmap on OpenStreetMap with GMAP.NET1.7 and GHEAT.NET

I would like to create a heatmap for many given points on a map based on OpenStreetMap.

I am working on C# VS2013 WPF.

I have checked the C# code at:

http://greatmaps.codeplex.com/
http://www.codeproject.com/Articles/88956/GHeat-NET

But, the Gheat.net (built at 2010) was built on GMAP.net v1.4.9.4 and my GMAP.net is 1.7 (built at 2015).

The authors added two files that define some new classes about points.

I got some compile errors when I added them to GMAP.NET 1.7 C# code.

For example,

public Point(Size sz)
{
this.x = sz.Width;
this.y = sz.Height;
this._data = null;
this._weight = null;
}

Size was not defined in GMAP.NET 1.7 but it was in GMAP.1.4.

Can anyone recommend other open source libs that support building heatmap on OSM?

Any help would be appreciated.