DPlot

This has been one of the more frustrating things I've encountered with DPlot: uninstall surveys that complain about not being able to do something that DPlot can do, but leave no e-mail address so that I can respond. I don't see a good way around this, but maybe mentioning the perceived problem here will help somebody else:

features: when I tried to use DPlot to plot contour of a lake, the generated contour doesn't follow the true shoreline well. My guess is that the triangulation process created some bad triangles which are purely artificial. I think this might be something you want to work on the further improve the software.

other: Tecplot does contour plots for irregular boudnary problem very well.

Tecplot is no doubt a fine program, but it cannot possibly do this either. That isn't a limitation of Tecplot or DPlot, but a limitation of your input. Think about it: How can a program possibly figure out where the edges of a surface should be based on nothing more than randomly-placed X,Y,Z data? There simply isn't enough information there to guess at the boundary. DPlot's "Define Boundary" command allows you to correct the boundary easily enough. See, for example, http://www.dplot.com/define-boundary.htm.

It may be possible that if your data is evenly-spaced in X and Y that Tecplot makes some intelligent guesses about where the boundary should be. But even then, it is only a guess. Given only X,Y,Z, the only way to ensure that you get the correct boundary is to tell the program where the boundary is.