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Updating Brätlistellen Data ​

The frontend includes a pre-processed TypeScript map of public fire pits (Brätlistellen) to cross-reference with OpenStreetMap data and provide external links to braetlistellen.ch within the MapViewer's feature popups.

The data is stored statically in frontend/src/assets/braetlistellen.ts to ensure fast load times and no runtime API overhead.

Update Process ​

If the original UMap dataset gets updated, you can refresh the local file using the following Python script. The script downloads the UMap GeoJSON layer, projects the coordinates from EPSG:4326 (WGS 84) to EPSG:2056 (LV95, as used by Swisstopo), and outputs a TypeScript array.

Dependencies ​

Ensure you have pyproj and requests installed:

bash
pip install pyproj requests

Conversion Script ​

Run the following script from the project root. It will fetch the latest layer and format it directly into the braetlistellen.ts file:

python
import json
import requests
from pyproj import Transformer

# UMap Datalayer URL
UMAP_URL = "https://umap.osm.ch/de/datalayer/2360/4d04ab84-f19a-4892-80bf-cb26ed4d19fb/"
OUTPUT_FILE = "frontend/src/assets/braetlistellen.ts"

print("Fetching latest UMap data...")
response = requests.get(UMAP_URL)
response.raise_for_status()
data = response.json()

print("Projecting coordinates...")
# OpenLayers uses EPSG:2056
transformer = Transformer.from_crs("epsg:4326", "epsg:2056", always_xy=True)

output = []
for feature in data.get('features', []):
    geom = feature.get('geometry')
    props = feature.get('properties', {})
    
    if geom and geom.get('type') == 'Point':
        lon, lat = geom['coordinates']
        x, y = transformer.transform(lon, lat)
        
        output.append({
            'x': x,
            'y': y,
            'name': props.get('name', ''),
            'url': props.get('description', '')
        })

print(f"Writing {len(output)} features to {OUTPUT_FILE}...")
with open(OUTPUT_FILE, 'w', encoding='utf-8') as f:
    f.write("export const braetlistellenData = ")
    json.dump(output, f, ensure_ascii=False, indent=2)
    f.write(";\n")

print("Done!")

After updating the data, rebuild the frontend or commit the newly updated file to version control.