On the Subject of Creating Coordinates

Coordinate creation causes confusion commonly.

Table 1: grid size formats

FormatHow to interpret
n 93×3 155×3 217×3 255×5 357×5 497×7
(n) 93×3 153×5 213×7 255×5 355×7 497×7
w×hw is the width, h the height of the grid.
h by wh is the height, w the width of the grid.
n*hn is the total size of the grid, w = n ÷ h.
n : wn is the total size of the grid, h = n ÷ w.

Table 2: grid location formats

[c,r]Top-left is [0,0].c r
letter number
Top-left is A1.
<r, c>Top-left is <0, 0>.r, cTop-left is 1, 1.
(c,r)Bottom-left is (0,0).c-r
letter-number
Bottom-left is A-1.
r, cBottom-left is “0, 0”.r/cBottom-left is 1/1.
[x]Traverse right then down[1]; Top-left is [0].xthTraverse right then down[1]; Top-left is 1st.
#xTraverse right then up[2]; Bottom-left is #1.四十七Traverse down then left[3]; top-right is 一.

Table 3: Chinese numerals

12345
678910

[1] Scanline order, also known as reading order, starts at the top-left, moves right across the row, and then continues likewise with each row from top to bottom.

[2] Cartesian order, also known as geometric order, starts at the bottom-left, moves right across the row, and then continues likewise with each row from bottom to top.

[3] Traditional Chinese reading order starts at the top-right, moves down the column, and then continues likewise with each column from right to left.