How to make a lake bathymetric map with QGIS - Tutorial

Bathymetric data requires some spatial processing on QGIS to represent lake bottom elevation contours and lake depth. This tutorial shows the complete procedure to analyse a bathymetric survey on the Lake Patillas in Puerto Rico with QGIS to generate:
Lake bottom DEM
Lake bottom contours
Lake depth DEM
Lake depth contours

Processing data can be downloaded from this link:

[ThoughtCog]

omg dude I was trying to do this with a TIN and I was driving myself crazy. I don't know how b-line interpolation works, but it looks like it's what I needed.

[bluejayway]

Thanks, I was trying to find the best interpolation method for a linear body of water with the datas I had from the field, which werent collected in the best way possible. But the Spline-B method worked just fine, better than the Krigging and IDW I was using with ArcMap/Pro.

[ervega]

Any comments regarding the selection of a Multilevel b-spline interpolation? What advantages has this interpolation method above others for bathymetry?

[mrx-inxh]

I'm just in the planning stages of a similar project and am wondering if the depth contours need to be shown as an elevation rather than depth. If that's the case, I would appreciate help on how to convert depths recorded in the field with a sounder, into elevation data. Thanks

[XinhLe]

would be great if a layout is added. good stuff

[fishingfool]

I'm here because I'm looking for ways to create custom maps for fishing with mfd fish finders.