Geographic font

geo_font.py

import fontforge
import json

from shapely.geometry import MultiPolygon, shape
from shapely.affinity import translate

font_file = "path/to/font.sfd" # path to sfd font file, created in FontForge GUI
geo_file = "path/to/features.geojson" # path to geographic features file

font = fontforge.open(font_file)
glyph_w = 1000 # glyph width
glyph_h = 800 # glyph height

with open(geo_file, "r") as f:
    features = json.load(f)["features"]

def scaled_xy(x, y, minx, miny, maxx, maxy): # scale coordinates to fit inside glyph
    scaled_x = (x - minx)/(maxx - minx)
    scaled_y = (y - miny)/(maxy - miny)
    return (scaled_x * glyph_w, scaled_y * glyph_h)

for i, feature in enumerate(features): # create a glyph for each feature
    mpoly = shape(feature["geometry"])
    
    new_geoms = []
    for part in mpoly: # handle features that straddle antimeridian
        if part.centroid.x < 0:
            new_geoms.append(translate(part, xoff=360.0, yoff=0.0, zoff=0.0))
        else:
            new_geoms.append(part)
    new_mpoly = MultiPolygon(new_geoms)

    bnds = new_mpoly.bounds # feature bbox

    font.createChar(i) # create a new glyph
    pen = font[i].glyphPen() # create a new glyph pen
    for j, part in enumerate(new_mpoly): # draw a glyph part for each feature part
        coords = scaled_xy(*part.exterior.coords[0], *bnds) # get glyph coordinates for feature point
        pen.moveTo(coords) # move the pen to the starting location

        for coords in part.exterior.coords[1:]:
            pen.lineTo(scaled_xy(*coords, *bnds)) # move the pen, drawing a line

        pen.closePath() # finally, close the glyph part
    
    pen = None # delete the pen

font.generate(font_file) # generate the font
font.save() # save the font