Displaying data in a hexagonal grid using Python

Question

What I'm looking for is a method or class that allows me to display a list of hexagons in a grid. Ideally, I could use some form of set-method to change the color / hatching / border of individual hexagons.

Hexagons are stored using the axial coordinate system described in by @amitp. But I can easily deduce their centers as xy-coordinates.

I feel there might be some solution hidden somewhere in hexbin or RegularPolyCollection . But the former is a histogram method, and the latter seems overly complex due to DPI scaling.

Does anyone know about a library that provides a hexagonal grid? It should not be in matplotlib. I am also very happy to use ASCII art or switch to R.

Answer 1

Here is an implementation that allows you to set a hexagonal cell of the desired color and also allow you to create custom border colors.

This is all done manually, it just took 1 hour using your link site. You may need to adapt it to your needs, but it seems to work.

from tkinter import * class HexaCanvas(Canvas): """ A canvas that provides a create-hexagone method """ def __init__(self, master, *args, **kwargs): Canvas.__init__(self, master, *args, **kwargs) self.hexaSize = 20 def setHexaSize(self, number): self.hexaSize = number def create_hexagone(self, x, y, color = "black", fill="blue", color1=None, color2=None, color3=None, color4=None, color5=None, color6=None): """ Compute coordinates of 6 points relative to a center position. Point are numbered following this schema : Points in euclidiean grid: 6 5 1 . 4 2 3 Each color is applied to the side that link the vertex with same number to its following. Ex : color 1 is applied on side (vertex1, vertex2) Take care that tkinter ordinate axes is inverted to the standard euclidian ones. Point on the screen will be horizontally mirrored. Displayed points: 3 color3/ \color2 4 2 color4| |color1 5 1 color6\ /color6 6 """ size = self.hexaSize Δx = (size**2 - (size/2)**2)**0.5 point1 = (x+Δx, y+size/2) point2 = (x+Δx, y-size/2) point3 = (x , y-size ) point4 = (x-Δx, y-size/2) point5 = (x-Δx, y+size/2) point6 = (x , y+size ) #this setting allow to specify a different color for each side. if color1 == None: color1 = color if color2 == None: color2 = color if color3 == None: color3 = color if color4 == None: color4 = color if color5 == None: color5 = color if color6 == None: color6 = color self.create_line(point1, point2, fill=color1, width=2) self.create_line(point2, point3, fill=color2, width=2) self.create_line(point3, point4, fill=color3, width=2) self.create_line(point4, point5, fill=color4, width=2) self.create_line(point5, point6, fill=color5, width=2) self.create_line(point6, point1, fill=color6, width=2) if fill != None: self.create_polygon(point1, point2, point3, point4, point5, point6, fill=fill) class HexagonalGrid(HexaCanvas): """ A grid whose each cell is hexagonal """ def __init__(self, master, scale, grid_width, grid_height, *args, **kwargs): Δx = (scale**2 - (scale/2.0)**2)**0.5 width = 2 * Δx * grid_width + Δx height = 1.5 * scale * grid_height + 0.5 * scale HexaCanvas.__init__(self, master, background='white', width=width, height=height, *args, **kwargs) self.setHexaSize(scale) def setCell(self, xCell, yCell, *args, **kwargs ): """ Create a content in the cell of coordinates x and y. Could specify options throught keywords : color, fill, color1, color2, color3, color4; color5, color6""" #compute pixel coordinate of the center of the cell: size = self.hexaSize Δx = (size**2 - (size/2)**2)**0.5 pix_x = Δx + 2*Δx*xCell if yCell%2 ==1 : pix_x += Δx pix_y = size + yCell*1.5*size self.create_hexagone(pix_x, pix_y, *args, **kwargs) if __name__ == "__main__": tk = Tk() grid = HexagonalGrid(tk, scale = 50, grid_width=4, grid_height=4) grid.grid(row=0, column=0, padx=5, pady=5) def correct_quit(tk): tk.destroy() tk.quit() quit = Button(tk, text = "Quit", command = lambda :correct_quit(tk)) quit.grid(row=1, column=0) grid.setCell(0,0, fill='blue') grid.setCell(1,0, fill='red') grid.setCell(0,1, fill='green') grid.setCell(1,1, fill='yellow') grid.setCell(2,0, fill='cyan') grid.setCell(0,2, fill='teal') grid.setCell(2,1, fill='silver') grid.setCell(1,2, fill='white') grid.setCell(2,2, fill='gray') tk.mainloop() 

I tried to comment my code correctly. If something seems unclear to you, please feel free to ask for an explanation.

Good luck Arthur Weiss.

NB: the script runs on python 3. The picture is a bit jagged. Improving your Tk canvas can add an anti-alias, as suggested at https://mail.python.org/pipermail/tkinter-discuss/2009-April/001904.html