Hey there! Let's break down your two PyQt5 + OpenStreetMap questions with free, straightforward solutions—no paid Google Maps required.

The easiest way to embed OSM in a PyQt5 app is using PyQtWebEngine, which lets you load and interact with web content directly in your Qt window. Here's a complete example:

First, make sure you have the required packages installed:

pip install pyqt5 pyqtwebengine

Then the code:

from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtWebEngineWidgets import QWebEngineView
import sys

class OSMViewer(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("OpenStreetMap in PyQt5")
        self.setGeometry(100, 100, 800, 600)
        
        # Create a web view to load OSM
        self.web_view = QWebEngineView()
        # Load OSM homepage, or specify a default location (e.g., Beijing with zoom level 10)
        self.web_view.load("https://www.openstreetmap.org/#map=10/39.9042/116.4074")
        self.setCentralWidget(self.web_view)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = OSMViewer()
    window.show()
    sys.exit(app.exec_())

This code creates a main window with a web view that loads the OSM website. You can tweak the URL to set a default map position, zoom level, or even add markers if you need more customization.

For this, we'll use Nominatim—OSM's free geocoding API that doesn't require an API key (just follow their usage policies, like limiting requests to 1 per second and setting a proper User-Agent).

First, install the requests library to handle API calls:

pip install requests

Here's a PyQt5 app that lets you input a location and fetch its coordinates:

from PyQt5.QtWidgets import (QApplication, QMainWindow, QWidget, QVBoxLayout, 
                             QLineEdit, QPushButton, QLabel)
import requests
import sys

class GeoLocator(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Get Lat/Lon from OSM")
        self.setGeometry(100, 100, 400, 200)
        
        # Set up UI elements
        central_widget = QWidget()
        self.setCentralWidget(central_widget)
        layout = QVBoxLayout(central_widget)
        
        self.place_input = QLineEdit()
        self.place_input.setPlaceholderText("Enter a location (e.g., Tiananmen Square, Beijing)")
        layout.addWidget(self.place_input)
        
        self.get_btn = QPushButton("Fetch Coordinates")
        self.get_btn.clicked.connect(self.fetch_coordinates)
        layout.addWidget(self.get_btn)
        
        self.result_label = QLabel("Latitude and longitude will appear here")
        layout.addWidget(self.result_label)
        
    def fetch_coordinates(self):
        place = self.place_input.text().strip()
        if not place:
            self.result_label.setText("Please enter a location first!")
            return
            
        # Call Nominatim API
        url = "https://nominatim.openstreetmap.org/search"
        params = {
            "q": place,
            "format": "json",
            "limit": 1,  # Only return the top match
            "addressdetails": 0  # Skip extra address data to reduce response size
        }
        # Set a custom User-Agent (required by Nominatim to identify your app)
        headers = {
            "User-Agent": "PyQt5GeoLocator/1.0 (your-email@example.com)"
        }
        
        try:
            response = requests.get(url, params=params, headers=headers)
            response.raise_for_status()  # Raise error if request fails
            data = response.json()
            
            if data:
                lat = data[0]["lat"]
                lon = data[0]["lon"]
                self.result_label.setText(f"Latitude: {lat}\nLongitude: {lon}")
            else:
                self.result_label.setText("Location not found—check your input!")
                
        except requests.exceptions.RequestException as e:
            self.result_label.setText(f"Request failed: {str(e)}")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = GeoLocator()
    window.show()
    sys.exit(app.exec_())

Notes for Nominatim usage: #

• Always set a unique User-Agent with your contact info—this helps OSM maintainers reach you if there are issues with your requests.
• Avoid making too many rapid requests (stick to 1 per second max) to avoid being blocked.

内容的提问来源于stack exchange，提问作者YouRos