Triton Bathymetry - Manual (Page 40)

Page 36
This equation and the values for ‘a’ and ‘b’ come from IHO Standards for Hydrographic
Surveys, Special Publication No. 44.
8.3.4 CUBE Uncertainty Layer
This layer is similar to the DTM standard deviation layer as it
represents the amount of variation within the number of
soundings used to determine the depth value. Shown below is
the uncertainty layer for the CUBE depth grid at 0.5ms:
What the uncertainty layer represents is the
total uncertainty value generated by the CUBE
algorithm. Areas with high uncertainty should
be reviewed in the Swath Editor of 3D Editor
to determine if the correct depth value was
selected by the CUBE algorithm
Looking at the image to the left the total
uncertainty values for most of the grid cells is
very low with only a few bright spots
representing the higher uncertainty values
located around the wreck in the center of the
grid.
8.3.5 CUBE Number of Hypotheses Layer
In some cases the CUBE algorithm will identify
more than one plausible solution for the depth
of a grid cell. Each solution is referred to as a
hypothesis. The depth value in the CUBE grid
is CUBE’s assessment of which hypothesis is
the correct one. A good example of what
could cause CUBE to identify multiple
hypotheses is surveying over a wreck where
within one grid cell there may be returns from
the wreck surface and also the seafloor
beneath it. The image shown to the right has
only 1 hypothesis for most of the grid surface,
0.5m grid
0.5m grid