dd-l1-london-parks-count
Map (reference ← swipe → agent)
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I've got inner-London parks (london_parks) and I'm sizing the corpus before commissioning a green-space accessibility study. How many of those parks come in at one hectare or more, what's their combined area in hectares, and what bounding box would I draw around that subset on a WGS84 map? Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array).
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System info
{
"adapter": "openrouter",
"model": "google/gemma-4-26b-a4b-it",
"base_url": "https://openrouter.ai/api/v1"
}
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Bash
ls -F
london_parks.fgb
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Write
/work/solve.py
content · 57 lines · py
import geopandas as gpd
def analyze_parks(file_path):
# Load the parks data
gdf = gpd.read_file(file_path)
# Print info to understand structure
print("Columns:", gdf.columns.tolist())
print("CRS:", gdf.crs)
print("First few rows:\n", gdf.head())
# Ensure we are working with a projected CRS to calculate area in meters
# If it's WGS84, we need to reproject to a suitable metric CRS (e.g., EPSG:27700 for UK)
if gdf.crs.is_geographic:
print("Reprojecting to EPSG:27700 for area calculation...")
gdf_projected = gdf.to_crs(epsg=27700)
else:
gdf_projected = gdf
# Calculate area in square meters, then convert to hectares (1 ha = 10,000 m^2)
gdf_projected['area_ha'] = gdf_projected.geometry.area / 10000.0
# Filter for parks >= 1 hectare
large_parks = gdf_projected[gdf_projected['area_ha'] >= 1.0].copy()
# Count
count = len(large_parks)
# Total area
total_area_ha = large_parks['area_ha'].sum()
# Bounding box in WGS84
# First, reproject the subset back to WGS84
large_parks_wgs84 = large_parks.to_crs(epsg=4326)
# Get bounds: (minx, miny, maxx, maxy)
bounds = large_parks_wgs84.total_bounds
bbox_wgs84 = [float(bounds[0]), float(bounds[1]), float(bounds[2]), float(bounds[3])]
return count, total_area_ha, bbox_wgs84
if __name__ == "__main__":
import json
count, total_area, bbox = analyze_parks('london_parks.fgb')
result = {
"count": count,
"total_area_ha": total_area,
"bbox_wgs84": bbox
}
with open('parks_summary.json', 'w') as f:
json.dump(result, f, indent=4)
print("\nSummary:")
print(json.dumps(result, indent=4))
Wrote /work/solve.py (1770 chars).
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Bash
python solve.py
Columns: ['id', 'name', 'class', 'geometry']
CRS: EPSG:27700
First few rows:
id ... geometry
0 2b746b97-b0ed-35cc-8eb2-28a64821d7d8 ... MULTIPOLYGON (((532381.849 178719.026, 532391....
1 669c73cb-2314-3f8b-9b24-14b7db998247 ... MULTIPOLYGON (((532435.728 178838.472, 532437....
2 bcdbe219-4769-3d9a-bec6-ba44b2f4301f ... MULTIPOLYGON (((532657.956 178707.481, 532664....
3 6cb3b89b-4f9b-3a9d-b011-504239533b00 ... MULTIPOLYGON (((532863.795 178778.075, 532901....
4 7f18bab8-e6fc-34fa-a945-d784358559bd ... MULTIPOLYGON (((532724.97 178944.094, 532756.2...
[5 rows x 4 columns]
Summary:
{
"count": 42,
"total_area_ha": 519.1620805430861,
"bbox_wgs84": [
-0.19932378751294652,
51.49147199538401,
-0.08248178747996572,
51.54706589542573
]
}
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Bash
ls -F
london_parks.fgb parks_summary.json solve.py
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