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Test Instructions

Given the (lat, lon) boundary points for the region, you must create a regular grid of 5001 x 5001 rectangular cells with the IPP at the center. In screen coordinates:

Note: We use a Great Sphere approximation of the Earth.

Each case supplies the 4 (lat,lon) points defining the corners of the search region, and the number of cells. Each cell must have the same height and width.

Your model should rate each cell based on the probability that the lost person will be located in that cell. This process is left to you and your individual model. You are encouraged to use all provided test case information as well as all layers needed as input to your model.

Ideally, your model works with probabilities. If so, the following will be true:

For now you must project these to an 8-bit grayscale image for display and scoring purposes. Pixel values range from 0 to 255, with 255 (white) being the highest relative value. (The scoring metric only considers rank order.) Our native format is grayscale PNG (color bands 'P' or 'L').

If you work in probabilities, your numbers will span several orders of magnitude. There are 25 million pixels in the image, so a uniform map assigns each cell a probability of about 4x10-8 (0.00000004). An actual map may have cell probabilities ranging several orders of magnitude above and below 10-8.The following suggested transform allows 17 distinctions at each order of magnitude from 1.0 down to 10-15 and even a few at 10-16:

V = 5 * log2(P) + 255
In Python using numpy this would be:
V = 5 * int(numpy.log2(P)) + 255
If P were the matrix of probabilities, then V is now the matrix of grayscale values, though they may require converting to integers with P.astype(int) before saving.

Lastly, you will be prompted to submit your grayscale image for analysis. Once submitted, we will rate your image and "close" the test case for now. The new rating will be used to update your model's overall rating and your leaderboard status will be updated.

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