Python Geometry API

This project provides a simple API built with FastAPI that takes a list of 2D points and generates a concave hull (alpha shape) based on a given alpha value. The API returns the coordinates of the shape's edges, which is useful for creating boundary shapes around scattered points.

Features

• 2D Concave Hull Calculation: Uses the alphashape library to compute the concave hull (alpha shape) of a given set of points.
• FastAPI: Provides a fast and interactive API with automatic documentation via Swagger UI.
• Simple Token Verification: Includes a verification token for secure at least a little bit the access to the API.
• Python 3.12: Built and deployed using Python 3.12.

Endpoints

• POST /2d_concave_hull/: Receives a JSON payload containing a list of 2D points and a verification token, and returns the alpha shape edges.

Request

POST /2d_concave_hull/?token=your_verification_token&alpha=0
{
  "points": [
    [0.0, 0.0],
    [1.0, 0.0],
    [1.0, 1.0],
    [0.0, 1.0]
  ]
}

Response

{
  "edges": [
    [[0.0, 0.0], [1.0, 0.0]],
    [[1.0, 0.0], [1.0, 1.0]],
    [[1.0, 1.0], [0.0, 1.0]],
    [[0.0, 1.0], [0.0, 0.0]]
  ]
}

Example of a request using python (inside Dynamo):

import urllib2
import json
def get_concave_hull(points2D, token, alpha = 0.0):
	base_url = "http://127.0.0.1:8000/" # Change the base URL when you deploy to production
	endpoint = "2d_concave_hull/"
	# Encode token to avoid errors
	my_token = urllib2.quote(token)
	parameters = "?token=" + my_token + "&alpha=" + str(alpha).replace(",", ".")
	url = base_url + endpoint + parameters
	headers = {'Content-type': 'application/json', "accept": "application/json"}
	data = json.dumps(dict(points=points2D))
	request = urllib2.Request(url, data, headers)
	try:
		response = urllib2.urlopen(request)
	except urllib2.HTTPError as e:
		raise Exception("The request was not successful.\n" + e.read())
	return response.read()

Local Development

Prerequisites

• Python 3.12
• Virtualenv

Setup

1. Clone the repository:

   git clone https://github.com/aecoder-br/python-geometry-api.git
   cd python-geometry-api

2. Create and activate a virtual environment:

   python3.12 -m venv .venv
   source .venv/bin/activate

   Alternatively, on Windows, you can use:

   py -3.12 -m venv .venv
   .venv\Scripts\activate

3. Install the dependencies:

   pip install -r requirements.txt

4. Create a .env file in the root directory of the project and add your verification token:

   VERIFICATION_TOKEN=your_verification_token
   

5. Run the application:

   uvicorn main:app --reload

6. Access the API documentation at http://127.0.0.1:8000/docs.

Contributing

Contributions are welcome! Please open an issue or submit a pull request.

License

This project is licensed under the MIT License. See the LICENSE file for more details.