Julia Mapping: A Practical Guide

Data mapping for people who just want the solutions.

This guide is designed specifically for non-programmers—academics, journalists, and researchers—who need to turn location data into insight without getting lost in the weeds of computer science. Experienced programmers looking for concrete examples of Julia in practical use will also find it of interest.

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Why Julia for Mapping?

  • Speed: Render complex geospatial layers in seconds.
  • Clarity: Syntax that easily translates to English.
  • Open Source: No expensive GIS licenses required.

Example, a State Bin map of the 2024 election

using CairoMakie
using ColorSchemes
using CSV
using DataFrames
using StateBins
df = CSV.read("data/educ_votes.csv", DataFrame)
df.total_votes = df.dem_votes .+ df.gop_votes
grownups = combine(groupby(df, :state), 
    :population => sum => :population, 
    :total_votes => sum => :total_votes,
    :gop_votes => sum => :gop_votes,
    :dem_votes => sum => :dem_votes)
grownups.margin = ((grownups.gop_votes .- grownups.dem_votes) ./ grownups.total_votes) .* 100
statebins_makie(grownups, state_col="state", value_col="margin",
                auto_size=false, 
                colorscheme=:coolwarm,
                title="2024 GOP Margin as a Percent of Adult (over 25) Population",
                colorbar_label="GOP Margin (%)",
                marker_size=50,
                font_size=12,
                margin_factor=0.1,
                show_colorbar=true)

StateBins map of 2024 Election

Table of Contents

From the book in PDF

Sample Chapter

Chapter 2 in PDF

A Google NotebookLM Deep Dive Review of the Book

A Short Google NotebookLM Explainer for the Book

Part of a Series

Forthcoming titles

  • Get started with the command line interface
  • Julia for speakers of English (and other languages)
  • Julia error messages and how to fix them
  • The very basics of statistics with Julia
  • Industrial strength data storage with Julia and PostgreSQL
  • Advanced mapping with Julia and PostGIS

Publisher

About the Author

Richard Careaga originally trained in geology and regional planning and worked preparing environmental impact statements, city plans and infrastructure programs and civil and military works projects. After a second career as a corporate finance lawyer he returned to combine his love of maps with a love of programming to combine the two.