The expression “x*2” on the ‘Size X’ input to Rectangular is because the ‘R_max’ slider value is the maximum radius of the circles, so the grid cells have to be twice as wide to keep them from overlapping.
The expression “x-1” on the ‘Extent Y’ input to Rectangular is because that component returns one more column and one more row of points than the ‘Extent X’ and ‘Extent Y’ values it receives. The extra column of points is used for the country/region labels. Then Shift List after Flip Matrix eliminates that first point in each row for the column labels (years). The “x-1” expression on the ‘Extent Y’ input is to avoid the off-by-one row issue that caused Zimbabwe to appear twice.
The ‘Points’ output of Rectangular is reversed because the list of countries is reversed if I didn’t. The grid rows are numbered from bottom to top and we want countries listed top to bottom.
PAUSE: This is turning into an exhaustive explanation of data trees so let me explain how to fish for answers yourself…
-
Connect text panels to see data trees before and after any component or set of components. There is a pattern to be recognized and matched, even without full understanding. Only wire text panels so they can be removed without affecting anything else.
-
Search the forum for examples of specific components like Flip Matrix and Create Set.
-
Try stuff and see what happens! Like undo that Reverse on the ‘Points’ output, remove or change an expression or invert wrap on Shift List. A little crude but be bold, the worst that can happen is freezing Grasshopper/Rhino because a data tree mismatch turns a few hundred items into hundreds of thousands (or worse).
-
Use this ‘Tree/List Viewer’ tool to examine data trees of geometry (points, circles, etc.):