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:

But, the (built at 2010) was built on v1.4.9.4 and my 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.