MapWinGIS is an ActiveX control for GIS development, with built-in support for many Raster and Vector formats. The scale of this project is about 190,000 lines of C++ code. I have significant contributions to this project, including the following:

    1.  Added many advanced drawing features like draw to a specific layer, and enhanced the existing drawing features so that the user can specify the the character of the lines or points when drawing.

     2. Fixed Unicode related bugs so the controls can handle wide chars correctly

     3. Fixed tons of memory related problem, including memory violation, memory leaks caused by improper use of C++ new/delete pair, memory leaks caused by COM interface, GDI resource leaking. 

     4. Provide workaround for a series stack overflow problem cause by the bug of MFC library. which has solved a long lasting problem that the control can not save dbf files larger than 20MB.

I had plenty of experience with COM/ActiveX technologies before this project. But this is first time I have dug so deep into COM and COM/.NET inter operation. And also, I have throughly studied Microsoft CRT and the CRT advanced debugging APIs, through tackling with those tough memory related problems

Here is a screen shot for the ActiveX control when displaying a world map:

For more information about MapWinGIS, please visit our website:

http://www.mapwindow.org/