crs-l1-paris-lambert93
Map (reference ← swipe → agent)
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Our heat-loss model won't accept the `paris_buildings` file in lat/lon. It needs the coordinates in metres using the standard official projection for the Paris region. Can you convert the buildings over so the model can ingest them? Please leave the attributes alone, and keep every geometry as a plain Polygon rather than turning it into a MultiPolygon. Write the result as a GeoPackage to `paris_buildings_lambert93.gpkg`, and use `id` as the key.
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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 /work
paris_buildings_wgs84.geojson
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Read
/work/paris_buildings_wgs84.geojson
1 {
2 "type": "FeatureCollection",
3 "name": "paris_buildings_wgs84",
4 "crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
5 "features": [
6 { "type": "Feature", "properties": { "id": "007591b9-c632-4d57-8bd2-144f82cfdd73", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 4 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3597498, 48.8570399 ], [ 2.3597608, 48.8570499 ], [ 2.3598145, 48.8571068 ], [ 2.3598435, 48.8571291 ], [ 2.359806, 48.8571492 ], [ 2.3597163, 48.8570555 ], [ 2.3597328, 48.8570478 ], [ 2.3597498, 48.8570399 ] ] ] } },
7 { "type": "Feature", "properties": { "id": "00fac4fe-168a-4116-b287-6a28f34c87df", "class": "hotel", "subtype": "commercial", "name": "Hôtel de Nice", "height": null, "num_floors": 7 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3558066, 48.8565792 ], [ 2.3558201, 48.8565761 ], [ 2.355847, 48.8566201 ], [ 2.3558588, 48.8566176 ], [ 2.3559027, 48.8566953 ], [ 2.3558801, 48.8567021 ], [ 2.3557818, 48.856724 ], [ 2.3557422, 48.8566535 ], [ 2.3557293, 48.8566307 ], [ 2.355756, 48.856591 ], [ 2.3558066, 48.8565792 ] ] ] } },
8 { "type": "Feature", "properties": { "id": "020eefa5-5685-4f26-bd27-5b2bbd276bec", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 7 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3572011, 48.8572525 ], [ 2.3572582, 48.8572755 ], [ 2.3572304, 48.8572879 ], [ 2.3571022, 48.8573444 ], [ 2.3570724, 48.8573171 ], [ 2.3570455, 48.8572899 ], [ 2.3570759, 48.8572763 ], [ 2.3570906, 48.857296 ], [ 2.3571193, 48.8572856 ], [ 2.3571116, 48.8572727 ], [ 2.3570988, 48.857277 ], [ 2.3570899, 48.8572701 ], [ 2.3571344, 48.8572517 ], [ 2.3570889, 48.8571907 ], [ 2.3571324, 48.8571707 ], [ 2.3571965, 48.8572473 ], [ 2.3572011, 48.8572525 ] ] ] } },
9 { "type": "Feature", "properties": { "id": "030e5772-d9af-4df1-9d7c-75d629eeca2d", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 5 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3576144, 48.8554387 ], [ 2.3575176, 48.8554725 ], [ 2.3574425, 48.8553782 ], [ 2.3575422, 48.8553435 ], [ 2.3576734, 48.8554183 ], [ 2.3576144, 48.8554387 ] ] ] } },
10 { "type": "Feature", "properties": { "id": "0468c0c0-8ee9-4000-a0c1-514c803c86ee", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3563341, 48.858202 ], [ 2.3563562, 48.8581947 ], [ 2.3565055, 48.8583418 ], [ 2.3562074, 48.8584452 ], [ 2.3561355, 48.8583597 ], [ 2.3560759, 48.8582882 ], [ 2.3561163, 48.8582744 ], [ 2.3563341, 48.858202 ] ] ] } },
11 { "type": "Feature", "properties": { "id": "04eec0bf-2cf3-436b-be28-5a17310179a4", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3593621, 48.8570356 ], [ 2.3593057, 48.8570501 ], [ 2.3593865, 48.8571298 ], [ 2.3592946, 48.8571673 ], [ 2.3592538, 48.8571923 ], [ 2.3591646, 48.8571264 ], [ 2.3591789, 48.8571161 ], [ 2.3591532, 48.8571066 ], [ 2.3591395, 48.8571171 ], [ 2.3591133, 48.8571072 ], [ 2.3591417, 48.8570895 ], [ 2.3591806, 48.8570624 ], [ 2.3591223, 48.8569857 ], [ 2.3591185, 48.8569791 ], [ 2.3592878, 48.8569268 ], [ 2.3593217, 48.8569787 ], [ 2.3593126, 48.8569826 ], [ 2.3593621, 48.8570356 ] ], [ [ 2.3592979, 48.8570841 ], [ 2.359273, 48.8570541 ], [ 2.3592526, 48.8570618 ], [ 2.3592822, 48.8570911 ], [ 2.3592979, 48.8570841 ] ] ] } },
12 { "type": "Feature", "properties": { "id": "051dfb19-9a71-4127-8522-63bf20232528", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3581223, 48.8581081 ], [ 2.3580964, 48.8580772 ], [ 2.3584975, 48.857856 ], [ 2.3585364, 48.8578936 ], [ 2.3584542, 48.8579474 ], [ 2.3583045, 48.8580455 ], [ 2.3581774, 48.8581295 ], [ 2.3581578, 48.8581275 ], [ 2.3581367, 48.8581253 ], [ 2.3581223, 48.8581081 ] ] ] } },
13 { "type": "Feature", "properties": { "id": "0707091a-10c6-4669-b6ed-55166847839e", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3573039, 48.8571135 ], [ 2.3572826, 48.8571208 ], [ 2.3572282, 48.8570585 ], [ 2.357222, 48.8570514 ], [ 2.3571732, 48.8569955 ], [ 2.3573448, 48.8569306 ], [ 2.3573136, 48.856893 ], [ 2.3574243, 48.8568539 ], [ 2.3575378, 48.8568138 ], [ 2.3575632, 48.8568051 ], [ 2.3576794, 48.8567629 ], [ 2.3578134, 48.8567165 ], [ 2.3578419, 48.8567066 ], [ 2.3579102, 48.8566833 ], [ 2.3580018, 48.8567988 ], [ 2.3579785, 48.8568061 ], [ 2.3578495, 48.8568467 ], [ 2.3578249, 48.8568547 ], [ 2.3577854, 48.8568662 ], [ 2.3576943, 48.8569005 ], [ 2.357741, 48.8569661 ], [ 2.3577062, 48.8569778 ], [ 2.3576648, 48.8569913 ], [ 2.3575549, 48.8570275 ], [ 2.3573039, 48.8571135 ] ], [ [ 2.3575937, 48.8568607 ], [ 2.3575442, 48.8568789 ], [ 2.3573572, 48.8569455 ], [ 2.3573748, 48.8569681 ], [ 2.3573225, 48.8569871 ], [ 2.3573677, 48.8570433 ], [ 2.3574221, 48.8570234 ], [ 2.3574185, 48.8570203 ], [ 2.3575226, 48.8569831 ], [ 2.3575195, 48.8569766 ], [ 2.3575983, 48.8569478 ], [ 2.3576068, 48.8569586 ], [ 2.3576598, 48.8569415 ], [ 2.3575937, 48.8568607 ] ] ] } },
14 { "type": "Feature", "properties": { "id": "07142702-50fc-4469-9fec-687e5719d2e5", "class": "", "subtype": "", "name": "", "height": null, "num_floors": 5 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3573095, 48.8587292 ], [ 2.3572626, 48.8586874 ], [ 2.3573894, 48.8586176 ], [ 2.3574152, 48.85864 ], [ 2.3574534, 48.858621 ], [ 2.3574255, 48.8585971 ], [ 2.3574634, 48.8585761 ], [ 2.3575101, 48.8586154 ], [ 2.3574314, 48.8586636 ], [ 2.3574052, 48.8586809 ], [ 2.3573095, 48.8587292 ] ] ] } },
15 { "type": "Feature", "properties": { "id": "071f77d5-75e3-4a98-89de-44f9a945aa44", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 6 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3565534, 48.8564198 ], [ 2.3565814, 48.8564286 ], [ 2.3566114, 48.8564826 ], [ 2.3564514, 48.8565169 ], [ 2.3564064, 48.8564365 ], [ 2.3564507, 48.8564258 ], [ 2.3565194, 48.8564091 ], [ 2.3565534, 48.8564198 ] ] ] } },
16 { "type": "Feature", "properties": { "id": "07949552-5a76-4fe6-ba80-efa54e8b0688", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 6 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3563841, 48.8579286 ], [ 2.3564188, 48.8579083 ], [ 2.3564408, 48.8578943 ], [ 2.3564942, 48.8579492 ], [ 2.3564604, 48.857966 ], [ 2.3564275, 48.8579796 ], [ 2.3563841, 48.8579286 ] ] ] } },
17 { "type": "Feature", "properties": { "id": "07ae479c-aa1a-4096-8c0d-4aa3d77d6c68", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3558582, 48.8583412 ], [ 2.3558805, 48.8583346 ], [ 2.3559207, 48.8583788 ], [ 2.3559434, 48.8584057 ], [ 2.3559652, 48.8583978 ], [ 2.3559826, 48.858419 ], [ 2.3559799, 48.8584201 ], [ 2.3559791, 48.8584223 ], [ 2.3559256, 48.8584407 ], [ 2.3559394, 48.8584582 ], [ 2.355925, 48.8584647 ], [ 2.3559556, 48.8585025 ], [ 2.3559606, 48.8585011 ], [ 2.3559961, 48.8585458 ], [ 2.3560893, 48.8585128 ], [ 2.3562946, 48.8587651 ], [ 2.3562546, 48.8587793 ], [ 2.3562817, 48.8588068 ], [ 2.3561865, 48.8588431 ], [ 2.3561537, 48.8588004 ], [ 2.3561489, 48.8588015 ], [ 2.3560707, 48.8587033 ], [ 2.3559915, 48.8586048 ], [ 2.3557874, 48.8583621 ], [ 2.3558582, 48.8583412 ] ] ] } },
18 { "type": "Feature", "properties": { "id": "085195c0-034d-4763-994a-37cf71a53f1b", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 3 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3570164, 48.8568157 ], [ 2.3570464, 48.8568041 ], [ 2.3571038, 48.8567839 ], [ 2.3571104, 48.8567891 ], [ 2.3571663, 48.8567698 ], [ 2.3572235, 48.8567482 ], [ 2.357284, 48.8567257 ], [ 2.3573256, 48.8567861 ], [ 2.357207, 48.8568283 ], [ 2.3570701, 48.8568769 ], [ 2.3570214, 48.8568214 ], [ 2.3570164, 48.8568157 ] ] ] } },
19 { "type": "Feature", "properties": { "id": "08e6b740-11e7-434c-8387-97797166f85a", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": 5 }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3573754, 48.8587838 ], [ 2.3573095, 48.8587292 ], [ 2.3574052, 48.8586809 ], [ 2.3574314, 48.8586636 ], [ 2.3574943, 48.8587156 ], [ 2.35745, 48.858741 ], [ 2.3574313, 48.8587518 ], [ 2.3573786, 48.858782 ], [ 2.3573754, 48.8587838 ] ] ] } },
20 { "type": "Feature", "properties": { "id": "0955376b-191f-4230-85e0-7c79b20a94ba", "class": "apartments", "subtype": "residential", "name": "", "height": null, "num_floors": null }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 2.3576954, 48.8575906 ], [ 2.3576496, 48.857536 ], [ 2.3578871, 48.8574519 ], [ 2.3579379, 48.8574355 ], [ 2.3579755, 48.8574873 ], [ 2.3579546, 48.8574944 ], [ 2.3579672, 48.8575123 ], [ 2.3578471, 48.8575511 ], [ 2.3577027, 48.8575994 ], [ 2.3576954, 48.8575906 ] ] ] } },
0:30
Write
/work/solve.py
content · 49 lines · py
import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon
def ensure_polygon(geom):
"""
Ensures that the geometry is a Polygon.
If it's a MultiPolygon, it returns the first part (as per instruction to keep every geometry as a plain Polygon).
Note: The instruction says 'keep every geometry as a plain Polygon rather than turning it into a MultiPolygon'.
If a feature has a MultiPolygon, we should ideally handle it.
However, if the input is already Polygons, we just want to make sure we don't accidentally create MultiPolygons during projection.
"""
if isinstance(geom, MultiPolygon):
# If it's a MultiPolygon, we take the largest part or just the first part.
# Given the context of buildings, they are usually single Polygons.
return max(geom.geoms, key=lambda a: a.area)
return geom
def solve():
input_file = "/work/paris_buildings_wgs84.geojson"
output_file = "/work/paris_buildings_lambert93.gpkg"
target_crs = "EPSG:2154" # Lambert-93
# Load the data
gdf = gpd.read_file(input_file)
# Reproject to Lambert-93
gdf = gdf.to_crs(target_crs)
# Ensure all geometries are Polygons (not MultiPolygons)
# We apply the function to each geometry.
gdf['geometry'] = gdf['geometry'].apply(ensure_polygon)
# Ensure the ID is used as the primary key if possible,
# but GeoPackage handles this via the index or a column.
# The instruction says "use `id` as the key". In GPKG, we can set a column as primary key
# but often this means ensuring the 'id' column exists and is used.
# Let's make sure 'id' is indeed a column.
if 'id' not in gdf.columns:
# If id is the index, reset it
gdf = gdf.reset_index()
# Write to GeoPackage
gdf.to_file(output_file, driver="GPKG")
print(f"Successfully converted {len(gdf)} buildings to {output_file}")
if __name__ == "__main__":
solve()
Wrote /work/solve.py (1951 chars).
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Bash
python /work/solve.py
Successfully converted 330 buildings to /work/paris_buildings_lambert93.gpkg
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Bash
python -c "import geopandas as gpd; gdf = gpd.read_file('/work/paris_buildings_l...
Polygon 330
Name: count, dtype: int64
EPSG:2154
id ... geometry
0 007591b9-c632-4d57-8bd2-144f82cfdd73 ... POLYGON ((653023.358 6862079.654, 653024.174 6...
[1 rows x 7 columns]
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Bash
ls -l /work/paris_buildings_lambert93.gpkg
-rw-r--r-- 1 agent agent 245760 Jun 7 11:27 /work/paris_buildings_lambert93.gpkg
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