csv_to_map.py

# csv_to_map.py converts csvs containing states and percentanges and converts them to a format that can be imported
# into https://mapchart.net/usa.html
import sys
import json
import os.path

# constants
BRANCHES = [str(branch) for branch in range(2011, 2018)]


# empty_map_data creates a dictionary with the appropriate keys to be serialized into the json format that mapchart.net
# expects
def empty_map_data():
    return {
        "groups": {},
        "hidden": [],
        "background": "#ffffff",
        "borders": "#000000"
    }


# percentage_to_color transforms a percentage in the range of min_percentage to max_percentage to a color value in
# the gradient range #00c840 to #ff0040
def percentage_to_color(per):
    weight = (per - min_percentage) / percentage_range
    r = int((1.0 - weight) * 255)
    g = int(weight * 200)
    return '#%02x%02x40' % (r, g)


# parse command line parameters
if len(sys.argv) < 4:
    print("usage: python csv_to_map.py <dir> <min-percentage> <max-percentage>")
    sys.exit(1)

directory = sys.argv[1]

if not os.path.exists(directory):
    print("%s is not a valid path" % directory)
    sys.exit(1)

min_percentage = float(sys.argv[2])
max_percentage = float(sys.argv[3])
percentage_range = max_percentage-min_percentage

# for each branch
for branch in BRANCHES:
    map_data = empty_map_data()
    map_data["title"] = branch

    # open the csv file containing the states and percentages. skip the first line containing the headers then transform
    # the percentage for each state into a color and add the appropriate data to the map_data dictionary
    with open(os.path.join(directory, branch + ".csv")) as f:
        first = True
        box_number = 0
        for line in f:
            if first:
                first = False
                continue

            state, percentage = line.split(',')
            color = percentage_to_color(float(percentage))

            if color in map_data["groups"]:
                map_data["groups"][color]["paths"].append(state)
            else:
                box = "#box%d" % box_number
                map_data["groups"][color] = {
                    "div": box,
                    "label": "",
                    "paths": [state],
                }
                box_number += 1

    # create a new file and write the serialized map_data json to it.
    with open(os.path.join(directory, branch + "map.json"), "w+") as f:
        f.write(json.dumps(map_data, indent=4))