dd-l1-london-parks-count

Status: done
Score: 0.619
Duration: 0:36
Cost: 0.17¢
Model: deepseek/deepseek-v4-flash
Model error Retrospective assessed 2026-06-09T18:04:13Z

Map (reference ← swipe → agent)

0:00
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).
0:00
System info 
{
  "adapter": "openrouter",
  "model": "deepseek/deepseek-v4-flash",
  "base_url": "https://openrouter.ai/api/v1"
}
0:03 
Let me start by exploring the working directory to find the data files.
0:03
Bash ls /work/ 
london_parks.fgb
0:06 
Let me explore this file to understand its structure.
0:06
Bash python3 -c " 
python3 -c "
import geopandas as gpd
gdf = gpd.read_file('/work/london_parks.fgb')
print(gdf.head())
print(gdf.columns.tolist())
print(gdf.crs)
print(len(gdf))
"
                                     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]
['id', 'name', 'class', 'geometry']
EPSG:27700
317
0:23 
The data is in EPSG:27700 (British National Grid). I need to:

1. Filter parks with area >= 1 hectare
2. Count them
3. Calculate their combined area in hectares
4. Find the bounding box of the subset in WGS84 (EPSG:4326)

Let me write a Python script to do this.
0:23
Write /work/solve.py
content · 46 lines · py 
import geopandas as gpd
from shapely.geometry import box

# Read the parks
gdf = gpd.read_file('/work/london_parks.fgb')
print(f"Total parks: {len(gdf)}")
print(f"CRS: {gdf.crs}")

# Calculate area in hectares (CRS is British National Grid, units are metres)
# 1 hectare = 10,000 m²
gdf['area_ha'] = gdf.geometry.area / 10_000

# Filter parks >= 1 ha
subset = gdf[gdf['area_ha'] >= 1].copy()
print(f"Parks >= 1 ha: {len(subset)}")

total_area_ha = subset['area_ha'].sum()
print(f"Combined area: {total_area_ha:.2f} ha")

# Get bounding box in the original CRS (27700)
bbox_27700 = subset.total_bounds  # [xmin, ymin, xmax, ymax]

# Convert the bounding box to WGS84 (EPSG:4326)
# Create a GeoDataFrame with the bounding box polygon, then reproject
bbox_poly = box(*bbox_27700)
bbox_gdf = gpd.GeoDataFrame(geometry=[bbox_poly], crs='EPSG:27700')
bbox_wgs84 = bbox_gdf.to_crs('EPSG:4326')

bounds_wgs84 = bbox_wgs84.total_bounds  # [xmin, ymin, xmax, ymax]
print(f"BBox WGS84: {bounds_wgs84.tolist()}")

# Build output
import json
output = {
    "count": int(len(subset)),
    "total_area_ha": round(float(total_area_ha), 6),
    "bbox_wgs84": [round(float(bounds_wgs84[0]), 6),
                   round(float(bounds_wgs84[1]), 6),
                   round(float(bounds_wgs84[2]), 6),
                   round(float(bounds_wgs84[3]), 6)]
}

with open('/work/parks_summary.json', 'w') as f:
    json.dump(output, f, indent=2)

print(json.dumps(output, indent=2))
Wrote /work/solve.py (1459 chars).
0:25 
Let me run the script.
0:25
Bash cd /work && python solve.py 
Total parks: 317
CRS: EPSG:27700
Parks >= 1 ha: 42
Combined area: 519.16 ha
BBox WGS84: [-0.20085078891494373, 51.491002026277656, -0.08053542602197632, 51.54874587242965]
{
  "count": 42,
  "total_area_ha": 519.162081,
  "bbox_wgs84": [
    -0.200851,
    51.491002,
    -0.080535,
    51.548746
  ]
}
0:28 
Let me verify the output file was written correctly.
0:28
Read /work/parks_summary.json 
     1	{
     2	  "count": 42,
     3	  "total_area_ha": 519.162081,
     4	  "bbox_wgs84": [
     5	    -0.200851,
     6	    51.491002,
     7	    -0.080535,
     8	    51.548746
     9	  ]
    10	}
0:35 
The output looks good. Let me check the task - the key asked for is `bbox_wgs84` but the user said `bbox` as `[xmin, ymin, xmax, ymax]`. Let me re-read.

"Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Wait, the user said "and what bounding box would I draw around that subset on a WGS84 map?" and then "Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Actually re-reading: "and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)" - hmm, but the user wrote in the main instruction "bbox" but then in the parentheses clarified. Let me check again:

"Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Actually the user says "bbox" not "bbox_wgs84" - wait, let me re-read carefully:

"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)."

The user says "bbox" - no, they say "bbox_wgs84". Let me check again:

"Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Actually wait, looking at the exact quote: "Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Hmm, but my output has "bbox_wgs84". Let me re-read the user's instruction one more time:

"Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

So the key is "bbox_wgs84" - that's exactly what I have. Wait, I'm reading it as "bbox_wgs84" but I keep second-guessing. Let me just re-read carefully...

The user wrote: "Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Yes, it's "bbox_wgs84" - that's what I've got. The output is correct.

Wait, I see "bbox" in the original question: "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)."

Hmm, actually the user says "bbox" and then "bbox_wgs84" - let me look at the actual user prompt: "Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Wait I think the user wrote "bbox" as the key name but then in parentheses clarified. Let me re-read the exact original message:

"Output parks_summary.json with keys count, total_area_ha, and bbox_wgs84 (as a [xmin, ymin, xmax, ymax] array)."

Yes, it's "bbox_wgs84" - matches what my output has. Good.
0:35