I realize you currently use the TIN algorithm, and I are looking into Kriging use for side-scan data.

Why not add additional algorithms to the contour creation capability as well? I've noticed that the Navico Insight Genesis Social Map page often has more accurate contour creation from the same Lowrance data set, and they utilize Kriging. There are also other algorithms that may work even better, such as "Thin Plate Spline". There are open source libraries that implement these algorithms, which you may be able to use them quite simply.

Check out the research paper here for a comparison of algorithms.

I agree that it would be nice to have some options here. The main issue would be getting some of these other methods to be performant with large data sets of perhaps a few million points, but it is something we are looking into. Thanks for the link to the paper - interesting read.