Creating map images for weather alerts: Generate or screenshot?

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1

Hey folks,

I’m working on a weather alert app that uses the US National Weather Service API. I want to include a map image showing the alert area. Right now, I can make an interactive map with Leaflet and draw the alert boundaries. But I’m stuck on how to grab just the part of the map I need as an image.

Does anyone know if there’s a way to generate an image directly from map tiles, zoom level, and overlay info? Or should I go the headless browser route and take a screenshot? It feels clunky, but maybe that’s the best option?

I’m also open to other mapping tools if they’d work better for this. Any ideas?

def get_weather_alert_map(alert_data):
    # Pseudocode for what I'm trying to do
    map_area = create_map(alert_data['bounds'])
    add_alert_overlay(map_area, alert_data['alert_type'])
    return generate_image(map_area)  # This is the part I'm unsure about

# How to implement generate_image()?

Thanks for any help you can give!

2

I’ve faced a similar challenge while working on a weather app project. I experimented with different methods and eventually found that using a headless browser such as Puppeteer or Selenium for screenshots works surprisingly well. I set up a headless Chrome instance, loaded my Leaflet map with the alert boundaries, and used its screenshot capability to capture the exact map area along with all custom overlays. This approach delivers a true-to-display image without manual stitching. Although performance might be a concern for very high traffic, it remains an efficient solution for many applications. For more demanding scenarios, server-side rendering libraries could be considered as a viable alternative.

3

For your weather alert app, consider using server-side rendering libraries such as Mapnik or Cairo. These tools allow you to generate map images programmatically without relying on a browser. By fetching the necessary map tiles and then rendering them with your alert overlays, you can output a static image file.

This method might require additional setup, but it offers greater control and efficiency over the direct screenshot approach, making it a more reliable long-term solution.

4

have u looked into mapbox static images api? it lets u generate map images with custom overlays n stuff. might be easier than screenshotting. you’d just need to convert ur alert boundaries to geojson n send it with the api request. could be worth checking out