Ruby Can Now Draw Maps — And I Started With Ice Cream

January 7, 2026

How libgd-gis turns Ruby into a real GIS engine

For many years, Ruby quietly missed something important.

Yes, Ruby is amazing at APIs, data processing, background jobs, and web platforms — but when it came to maps, graphics, and spatial data, Ruby was forced to step aside and let other languages do the work.

If you wanted to draw a map, generate tiles, or visualize geographic data, you had to reach for:

• ImageMagick
• QGIS
• Python
• Node
• or external GIS pipelines

Ruby was no longer a first-class citizen in the world of images and maps.

That changed when I built ruby-libgd, bringing a real native raster engine back to Ruby.

And now, with libgd-gis, Ruby doesn’t just draw images — it draws the world.

It started with something simple: ice cream 🍦

I didn’t start this project with satellites or scientific datasets.

I started with a simple question:

What if I map all the ice-cream shops in my city?

Everyone loves ice cream. And suddenly GIS doesn’t feel scary — it feels fun.

Using libgd-gis, I took a dataset of ice-cream shops in Paraná (Argentina) and generated this map:

Paraná — Ice Cream Map

Each pin on that map is:

• read from data
• projected from longitude and latitude
• drawn as an icon
• labeled with its name
• rendered into a PNG

All done in Ruby. No external GIS software. No cloud services. No Mapbox.

Just Ruby drawing a map.

From ice cream to museums

Once you can map ice-cream shops, the next step is obvious:

What else can we map?

So I mapped museums.

This produced:

Paraná — Museums Map

Now this isn’t just playful — it’s cultural data. It shows how GIS connects geography to meaning.

This is what spatial computing really is: not just coordinates, but stories on a map.

Then I tried something bigger… the whole planet

After mapping a city, a dangerous thought appears:

If Ruby can map a city… can it map the world?

So I took a dataset of the highest mountain peaks on Earth and told Ruby to draw them.

The result:

World Peaks Map (insert world_peaks.png)

And then regional versions:

• America

• Europe

• Asia

This is not a toy anymore. This is cartography — powered by Ruby.

The Ruby that draws maps

Here is the exact code that produced one of those world maps:

require "json"
require "gd/gis"

AMERICA = [-170, -60, -30, 75]

map = GD::GIS::Map.new(
  bbox: AMERICA,
  zoom: 4,
  basemap: :carto_light
)

peaks = JSON.parse(File.read("picks.json"))

map.add_points(
  peaks,
  lon: ->(p) { p["longitude"] },
  lat: ->(p) { p["latitude"] },
  icon: "peak.png",
  label: ->(p) { p["name"] },
  font: "./fonts/DejaVuSans.ttf",
  size: 10,
  color: [0,0,0]
)

map.render
map.save("output/america.png") 

This is GIS written in Ruby.

No Python. No Mapnik. No QGIS. No shell scripts.

Ruby → C → pixels → maps.

What is libgd-gis?

libgd-gis is a geospatial rendering layer for Ruby, built on top of ruby-libgd.

ruby-libgd gives Ruby:

• fast pixel access
• image formats
• filters
• shapes
• native performance

libgd-gis adds:

• geographic projections
• bounding boxes
• basemaps
• icon layers
• labels
• map rendering

Together, they turn Ruby into a map engine.

The gem is live:

https://rubygems.org/gems/libgd-gis

The API and specs are still being stabilized — but the engine already works, and every image in this article was generated using it.

Why this matters

Ruby is used to build:

• logistics platforms
• fintech systems
• city dashboards
• tourism apps
• disaster-response software
• scientific tools

All of those need maps.

For years, Ruby had to hand that work to other ecosystems.

Now it doesn’t.

With libgd-gis, Ruby can render spatial data, generate map tiles, and produce cartographic images inside its own runtime.

Ruby is becoming a visual, spatial language again.

And it all started with ice cream.