Hi Edward,
You should use the mesh surface if you want to display an irregular set of points. Otherwise the grid surface dimensions are controlled from the GridSizeX and GridSizeZ properties of the surface. For more information you can check out the following topics:
http://helpdotnetvision.nevron.com/UsersGuide_ChartTypes_Surface_Mesh_Surface.html
http://helpdotnetvision.nevron.com/UsersGuide_ChartTypes_Surface_Grid_Surface.html
Hope this helps - let us know if you meet any problems or have any questions.
BTW 2015 release will feature a series called cloud point which will allow the display of very large cloud points (1-2M).

Best Regards,
Nevron Support Team

If I have 2D data which I would normally plot using NPointSeries, but instead, because of the large amount of data, opt to use a NGridSurfaceSeries to create a flat Contour chart (like a 3D histogram, but smooth), how do i control the axes tick values to display my original values - NOT the grid number?

This is the original NPointSeries plot:



And this is the Contour chart equivalent, but as you can see, it uses its own axes tick and label formats. Also, the right-side axis should be on the left side. I want them to be like above!!



Any ideas?