Creating A Web Application with Python

Steps for creating a web application with Python for both the front-end and back-end: 

1. Create a virtual environment: It’s a good practice to create a separate virtual environment for your project. This allows you to manage dependencies and keep your system organized. You can use tools like virtualenv or conda to create a virtual environment.

2. Install the necessary libraries: You’ll need to install libraries for the web framework, forms handling, and file processing. For example, you can use Flask for the web framework, Flask-WTF for forms handling, and Fiona for file processing. You can install these libraries using pip.

3. Create a Flask app: Create a file app.py and import Flask and other necessary libraries. Create a Flask app and define routes for handling the requests.

4. Create forms: Use Flask-WTF or WTForms to create forms for handling user input. You can create forms for file upload, user registration, and other functions.

5. Handle file processing: Use Fiona to handle the shapefile processing, and the douglas-peucker package to perform the line simplification.

6. Handle user authentication: Implement user authentication using cookies or sessions.

7. Create template files: Create template files using Pyjade or another templating engine to define the structure of the web pages.

8. Run the app: Run the app using flask run in the command line. The app will be available at http://localhost:5000/ by default.

Keep in mind that this is a high-level overview of the process. There are many details and considerations to take into account when building a web application.