Surface weather analysis United States, temperature and dewpoint are plotted in degrees Celsius. The wind barb points in the direction from which the wind is coming. Each full flag on the wind barb represents of wind, each half flag represents . When winds reach , a filled in triangle is used for each of wind. In the United States, rainfall plotted in the corner of the station model are in inches. The international standard rainfall measurement unit is the millimeter. Once a map has a field of station models plotted, the analyzing isobars (lines of equal pressure), isallobars (lines of equal pressure change),
Closest pair of points problem left of the dividing line we have to compare the distances to the points that lie in the rectangle of dimensions bordering the dividing line on the right side, as shown in the figure. And what is more, this rectangle can contain at most six points with pairwise distances at least . Therefore, it is sufficient to compute at most left-right distances in step 4. The recurrence relation for the number of steps can be written as , which we can solve using the master theorem for divide-and-conquer recurrences to get . As the closest pair of points define an