qc2c

Quick Coordinates To Country - QC2C

Quick Coordinates To Country (QC2C) provides fast and (mostly) offline country check, based on provided coordinates.

About

This project aims at creation of standard, approximate offline check whether coordinates are within countries borders and return country code in ISO Alpha 3.

Approximate borders were created in main.py with:

• convex hull of a country
• geometry.simplify to reduce amount of points
• multiple iterations to remove unnecessary border points with smoothed curves

Compression

Results were compressed with gzip to reduce files size and make them accessible for javascript applications, as browsers have native support for this compression algorithm.

It is possible that other compression algorithms (such as Brotli) would provide smaller size, but they are not standard yet.

How to use

1. host world + sectors manifests on the web or add them to your project
2. Check which sector contains coordinates data
3. Check which country from sector contains coordinates

Example scripts are provided in example_use folder.

How to generate files

1. provide countries.json

2. provide us_states.json

3. provide world_sectors.json manifest

4. run main.py to generate world_sectors_x.json from provided files

   2023.12.24: Stage 1 current total runtime: ~900 seconds

5. Optional: run preview_world_sectors.py to check sector map for artifacts

stages 3+ produce .json.gz files!

Politics

1. This project is NOT a political matter
2. We do NOT move borders or decide which land belongs to whom
3. QC2C is offline approximation and WORKS ONLY ON LAND - sea borders are not supported!
4. If you do not agree with provided borders, don't use it! Make your own or something.
5. Keep your political views out of discussions, commits and merge requests.

Roadmap

1. Shore Line Reduction: sea borders can be greatly reduced, but this requires iteration through points; coming in stage 2

2. Rectangularization x Triangulation - islands can be represented as squares or triangles, if they would not intersect with anything else. Shore lines can also be represented as straight line (union of original polygon and rectangle)

3. Voronoi Diagram - Voronoi diagram allows to easily create separation regions, but it works for points only. Maybe it could be used for polygons too? ; coming in stage 3

4. Tests: 0. Verify output against input data - all coordinates assigned to input coutry should be part of it in output!

   1. set of pairs (coordinates, country_code) that generated output should match;
   2. The trickier the pairs (e.g. regions with mixed spots or irregular borders), the better testing set;
   3. Basic testing would be to generate a net of points created from data_input, covering all land with assigned country code, but this testing would force specific accuracy (border irregularities beyond net width won't be detected)