Need Help | Understanding Parameters for Bathymetry Plotting

[Aman Kumar Meena]

"Hi everyone,

I'm currently working on plotting bathymetry data, and I'm encountering some challenges. I have two sets of data available (diffuse & imaging): one set contains seven parameters including (x, y, v, w, etc.) but lacks a z parameter, and the other set, obtained from imaging, includes the z parameter. However, when attempting to plot the imaging data, I'm not getting the expected bathymetry visualization. I think that there might be an another file (as attached) in the dataset with covis.grid.type as bathy which is missing or may be i am in the wrong direction.

Could anyone guide me on which particular parameter or combination of parameters should I use to plot the bathymetry or base surface? Any insights or suggestions would be greatly appreciated! Thanks in advance!"

[K. G. Bemis]

Hi everyone

As noted in the description at https://sciviscontest2024.github.io/data/, the diffuse mode data are 2D fundamentally. So, they don't have a z parameter as they are assumed to sit directly on the bathymetry.  We've (the COVIS team) have never merged the bathymetry into the diffuse data but just drape it on top.  Since we work almost entirely in Matlab, this is simple.

Bathymetry data is available in separate files at https://github.com/COVIS-Sonar/postprocessing/tree/master/master_program/Inputs.  There are 3 versions, 2018, 2019a, and 2019b.  COVIS was recovered and redeployed during summer of 2019 so the grid alignment probably changed (but not by a lot).  I'm not entirely sure which version I usually use.  The origin of the grid should be COVIS's location and the grid should align with the imaging and diffuse data files. The (x,y,z) data are in (covis.grid.x,covis.grid.y,covis.grid.v), respectively.  Sorry, the interpolation of the data onto the uniform grid spits the output to the "v" variable whether it's the elevation (normally z) or the backscatter intensity (otherwise I).  I'm so use to this that I didn't realize it would be confusing.

Let me know if this doesn't solve all the confusions.

Karen