Wednesday, November 16, 2011

Water Volume Analysis

CI BioBase is powerful! The centralized (online) nature of our System allows us to offer new features to our customers and make them available to trips that have already been uploaded to the System. A perfect example is our recently pushed out water volume analysis feature that is included in the standard report generated from every trip.

We employ a TIN (triangulated irregular network) to provide total water volume of a water body in cubic meters. A TIN is a vector representation of a lake bottom produced with irregularly distributed lines and nodes with 3D coordinates arranged in a network of nonoverlapping triangles. Since the BioBase System already uses an X, Y, and Z coordinate system for bathymetry, we can use a TIN for water volume analysis. An advantage of using a TIN is that the points of a TIN are distributed variably using an algorithm to determine which points are most necessary for an accurate representation of the lake bottom.
Actual covered water volume is based on the surveyed area only. In addition to actual, we also offer the total water body water volume that is based on a universal kriging algorithm that estimates contours (using statistical analysis of actual data) to the shapefie boundary. TIN analysis will be more accurate with more data points gathered with you Lowrance HDS depth finder. However, we have found that there are diminishing returns when adding more data points to improving the accuracy of the water volume analysis. Here are a couple trips on a 3.2 acre lake for comparison:

Less data collected (1019 data points):
More coverage (1546 data points):
Both trips merged together:

"Actual" represents the total surface area of the water body sampled with your HDS sonar unit. Although we also show acres covered, "Total" represents total acreage of the shapefile. Total Lake Volume represents total volume using the TIN analysis with kriged estimates using the actual data points. More data points means more accurate contours and more accurate volume. More variability in the contours could mean more places for water to fit in the pond. All relative to the water body size, when data points increased from 1019 to 1546 and actual coverage increases from 59% to 90%, total volume increased by ~6k cu. m. However, when merged together (using our trip merge function) and data points increase from 1546 to over 2500, total water volume only increases by ~300 cu. m.

One way to potentially add more actual coverage to this trip would be to cross some of these with vertical zig zags. We provide the tools and allow you to decide how to maximize them.

Bathymetric and vegetation mapping is easy with the automated CI BioBase System. We're changing perspectives on what it mean to map and who can do it.

If you have any questions about CI BioBase, give us a call or email us at email@contourinnovations.com

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