Blind Map — Tactile Map for the Visually Impaired

A 3D-printable tactile map that helps blind people learn geography by touch.

What is this?

This project generates STL files for 3D printing a tactile map. The map is designed so a blind person can:

What	How it feels
Country borders	Raised ridge (1.2 mm) that follows the terrain under the finger
Terrain	4 tactile plateaus: sea / lowland / plateau / mountains (0/1/2/3 mm)
Sea	Wavy texture
Capitals	Small bumps
Country numbers	Raised 7-segment digits (like a calculator), 1–32
Legend	Braille country list + texture samples (sea, border, city)
Alphabet cards	Raised Latin letter next to its braille cell, for learning braille

The map splits into 4 puzzle pieces (200×160 mm each) that snap together with tabs and slots. Legends and alphabet cards come in two languages: English and Serbian (Gajica braille, 30 letters including Č Ć Dž Đ Lj Nj Š Ž).

What You Get

9 print-ready STL files in data/output/printready/:

File	Contents
tactile_map.stl	The full 400×320 mm map in one piece
card_1.stl … card_4.stl	The same map split into 4 puzzle cards
card_legend.stl	Numbers 1–32 → capital names in English braille
card_legend_sr.stl	Numbers 1–32 → country names in Serbian braille
card_alphabet.stl	English braille alphabet learning card (26 letters)
card_alphabet_sr.stl	Serbian braille alphabet learning card (30 letters)

Every output is a single watertight two-manifold, verified by mesh_diagnostics.py — no inverted normals, internal cavities, or self-intersections.

Region Covered

Europe, Middle East, North Africa, Caucasus: 5°–70° E, 12°–55° N. 32 countries get a tactile number; countries too small for a raised digit are marked with their capital bump only.

How to Build

0. Install dependencies

python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt

1. Get the data

# Country borders (automatic, ~80 countries from geoBoundaries)
python core/prepare_data/download_geojson.py
python core/prepare_data/merge_geojson.py

# Elevation data (manual)
# Go to: https://www.ngdc.noaa.gov/mgg/global/
# Download ETOPO1_Bed_g_gmt4.grd
# Place in: data/input/

Data	What for	Source
Country borders	Ridges between countries	geoBoundaries
Elevation	Terrain (mountains, plains)	NOAA ETOPO1

2. Generate STL files

python core/build_all.py

Output: data/output/printready/ — the 9 STL files listed above.

3. Verify (optional)

python core/mesh_diagnostics.py

Prints a print-readiness report (watertight, normals, cavities, self-intersections) for every STL.

4. Print

Setting	Value	Note
Material	PLA	Common, cheap, safe
Infill	15–20%	How solid inside (lower = faster)
Layer height	0.2 mm	Each terrain plateau is exactly 5 layers

Project Structure

blind_map/
├── assets/                    # Images for this README
├── core/
│   ├── config.py              # Map region (bounding box)
│   ├── constants.py           # All tactile/physical parameters
│   ├── generate.py            # Mesh building blocks: terrain, water, capitals,
│   │                          #   numbers, braille, legend
│   ├── build_all.py           # ENTRY POINT: full print-ready build
│   ├── walls_buffer.py        # Border ridges (buffer + manifold extrude)
│   ├── split_cards.py         # Boolean split into 4 puzzle cards
│   ├── heal_mesh.py           # Solid prep + boolean union helpers
│   ├── clean_mesh.py          # Topology cleanup -> watertight manifold
│   ├── text_mesh.py           # Raised Latin letters for alphabet cards
│   ├── alphabet_card.py       # Braille alphabet learning cards (EN/SR)
│   ├── serbian_braille.py     # Serbian Latin (Gajica) braille tables
│   ├── serbian_legend.py      # Serbian legend card
│   ├── mesh_diagnostics.py    # Print-readiness verification
│   └── prepare_data/          # Data download & merge scripts
├── data/                      # Not in repo (too large)
│   ├── input/                 # ETOPO1 elevation grid
│   ├── countries/             # Downloaded border GeoJSONs
│   └── output/                # Generated files (printready/, previews/)
├── requirements.txt
└── README.md

Tactile Design

Parameter	Value
Full map size	400×320 mm
Single card	200×160 mm
Base thickness	6 mm
Terrain plateaus	0 / 1 / 2 / 3 mm (sea, lowland, plateau, mountains)
Border ridge	+1.2 mm above local terrain, 1.5 mm wide
Water waves	2 mm high, every 4 mm
Capital bumps	2 mm high, ⌀3 mm
Country digits	1.5 mm raised
Puzzle connectors	Tabs 8×4×3 mm, 0.5 mm clearance

Key design decision: the border is a low ridge riding on top of the local terrain, not a tall wall at a fixed height. A finger can trace a border continuously and still read the relief on both sides of it; tall walls used to bury small lowland countries entirely.