Hot Spot Sample Designs

Hot spot sampling is a 2d initial Ellipgrid model by Reference Search Strategy that was originally encoded as Ellipgrid PC by Oak Ridge National Laboratory. The goals of 2d hot spot sampling are to calculate:

   the probability of hitting or, conversely, missing an elliptical hot spot of a defined size;

   the maximum size of a hot spot that would, with a defined probability, be hit by a sample grid definition;

   a grid of samples based on finding a hot spot of a defined size with a distinct probability; and

   a grid of samples based on the cost to sample, the sample area definition, and a limited budget.

2D Ellipgrid calculates the relationship between hotspot size, grid density, cost, and probability for a variety of circumstances. These designs are useful in determining tradeoffs between cost, size of hot spot, and cost to implement; however, most sample designs are fairly dense grids and too expensive for many sampling budgets.

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There are four 2d hot spot sample designs in SADA: Hot Spot: Minimize Sample Size By Cost, Hot Spot: Minimize Sample Size By Hot Spot Definition, Hot Spot: Unknown Hot Spot, Hot Spot: Calculate Probability.

The concept of hot spot searches in two dimensions can easily be extended into the third dimension through the use of simulation. A grid is specified in three dimensions, and the locations of ellipsoids are simulated across the site. The likelihood of hitting such a hot spot is simply the ratio of simulated hits to total simulations. This provides an estimate of how effective a sampling grid will be at finding hot spots in subsurface. As with two dimensional hot spot searches, however, the grids can be too dense for practical sampling budgets.

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The only 3d hot spot sample design in SADA is 3d Hot Spot Search.