crs-l1-nyc-webmercator-cycleways
Map (reference ← swipe → agent)
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The `nyc_cycleways` file came out of our tile-renderer, but our web map client can't read the coordinates as they are. It needs plain lat/lon. Can you convert them over? Please leave the attributes alone, and make sure each geometry stays a plain LineString rather than turning into a MultiLineString. Write the result as GeoParquet to `nyc_cycleways_wgs84.geoparquet`, 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 -F
nyc_cycleways_webmercator.geoparquet
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Write
/work/solve.py
content · 42 lines · py
import geopandas as gpd
# Load the file
gdf = gpd.read_file('nyc_cycleways_webmercator.geoparquet')
# Print info to understand the data
print("Original CRS:", gdf.crs)
print("First few rows:")
print(gdf.head())
print("Geometry types:", gdf.geometry.type.unique())
# Convert to WGS84 (lat/lon)
gdf_wgs84 = gdf.to_crs(epsg=4326)
# Ensure geometry is LineString and not MultiLineString
# We can use explode if there are MultiLineStrings, but the user says
# "make sure each geometry stays a plain LineString rather than turning into a MultiLineString"
# This might mean they want to avoid the automatic conversion that some processes do,
# or they want to ensure that if a geometry is a MultiLineString, it is broken down into LineStrings.
# However, if they say "stays a plain LineString", it implies the source is likely LineStrings.
# Let'se ensure we explode any MultiLineStrings just in case, so every row is a single LineString.
if gdf_wgs84.geometry.type.contains('MultiLineString'):
print("Exploding MultiLineStrings to LineStrings...")
gdf_wgs84 = gdf_wgs84.explode(index_parts=False)
# The user wants 'id' as the key. In GeoParquet/GeoPandas, 'id' isn't a special "key"
# in the way a database index is, but I'll ensure it exists and is preserved.
# If they mean the index, I'll set the index to 'id'.
if 'id' in gdf_wgs84.columns:
gdf_wgs84 = gdf_wgs84.set_index('id')
else:
print("Warning: 'id' column not found.")
# Write to GeoParquet
gdf_wgs84.to_parquet('nyc_cycleways_wgs84.geoparquet')
print("Successfully saved to nyc_cycleways_wgs84.geoparquet")
print("New CRS:", gdf_wgs84.crs)
print("Geometry types:", gdf_wgs84.geometry.type.unique())
Wrote /work/solve.py (1682 chars).
0:40
Bash
python solve.py
Traceback (most recent call last):
File "/work/solve.py", line 4, in <module>
gdf = gpd.read_file('nyc_cycleways_webmercator.geoparquet')
File "/usr/local/lib/python3.14/site-packages/geopandas/io/file.py", line 316, in _read_file
return _read_file_pyogrio(
filename, bbox=bbox, mask=mask, columns=columns, rows=rows, **kwargs
)
File "/usr/local/lib/python3.14/site-packages/geopandas/io/file.py", line 576, in _read_file_pyogrio
return pyogrio.read_dataframe(path_or_bytes, bbox=bbox, **kwargs)
~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/pyogrio/geopandas.py", line 382, in read_dataframe
result = read_func(
path_or_buffer,
...<15 lines>...
**kwargs,
)
File "/usr/local/lib/python3.14/site-packages/pyogrio/raw.py", line 200, in read
return ogr_read(
get_vsi_path_or_buffer(path_or_buffer),
...<15 lines>...
datetime_as_string=datetime_as_string,
)
File "pyogrio/_io.pyx", line 1412, in pyogrio._io.ogr_read
File "pyogrio/_io.pyx", line 257, in pyogrio._io.ogr_open
pyogrio.errors.DataSourceError: 'nyc_cycleways_webmercator.geoparquet' not recognized as being in a supported file format.; It might help to specify the correct driver explicitly by prefixing the file path with '<DRIVER>:', e.g. 'CSV:path'.
1:04
Write
/work/solve.py
content · 45 lines · py
import pandas as pd
import geopandas as gpd
# Try reading with pandas first or specifically via geopandas with engine='pyarrow'
try:
gdf = gpd.read_parquet('nyc_cycleways_webmercator.geoparquet')
except Exception as e:
print(f"Failed to read with gpd.read_parquet: {e}")
# Fallback: try using pandas and then converting to geopandas
df = pd.read_parquet('nyc_cycleways_webmercator.geoparquet')
# We need to know which column is geometry. Let's assume 'geometry'
gdf = gpd.GeoDataFrame(df, geometry='geometry')
if gdf.crs is None:
# If CRS is not in the parquet metadata, we might need to set it.
# But GeoParquet usually stores it. Let's see.
pass
print("Original CRS:", gdf.crs)
print("First few rows:")
print(gdf.head())
print("Geometry types:", gdf.geometry.type.unique())
# Convert to WGS84 (lat/lon)
gdf_wgs84 = gdf.to_crs(epsg=4326)
# Ensure geometry is LineString and not MultiLineString
# Explode MultiLineStrings to LineStrings to satisfy "each geometry stays a plain LineString"
if any(gdf_wgs84.geometry.type.str.contains('MultiLineString')):
print("Exploding MultiLineStrings to LineStrings...")
gdf_wgs84 = gdf_wgs84.explode(index_parts=False)
# User wants 'id' as the key.
# In many contexts, this means the index should be the 'id' column.
if 'id' in gdf_wgs84.columns:
gdf_wgs84 = gdf_wgs84.set_index('id')
else:
print("Warning: 'id' column not found.")
# Write to GeoParquet
gdf_wgs84.to_parquet('nyc_cycleways_wgs84.geoparquet')
print("Successfully saved to nyc_cycleways_wgs84.geoparquet")
print("New CRS:", gdf_wgs84.crs)
print("Geometry types:", gdf_wgs84.geometry.type.unique())
Wrote /work/solve.py (1678 chars).
1:06
Bash
python solve.py
Original CRS: {"$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "ProjectedCRS", "name": "WGS 84 / Pseudo-Mercator", "base_crs": {"name": "WGS 84", "datum_ensemble": {"name": "World Geodetic System 1984 ensemble", "members": [{"name": "World Geodetic System 1984 (Transit)"}, {"name": "World Geodetic System 1984 (G730)"}, {"name": "World Geodetic System 1984 (G873)"}, {"name": "World Geodetic System 1984 (G1150)"}, {"name": "World Geodetic System 1984 (G1674)"}, {"name": "World Geodetic System 1984 (G1762)"}, {"name": "World Geodetic System 1984 (G2139)"}, {"name": "World Geodetic System 1984 (G2296)"}], "ellipsoid": {"name": "WGS 84", "semi_major_axis": 6378137, "inverse_flattening": 298.257223563}, "accuracy": "2.0", "id": {"authority": "EPSG", "code": 6326}}, "coordinate_system": {"subtype": "ellipsoidal", "axis": [{"name": "Geodetic latitude", "abbreviation": "Lat", "direction": "north", "unit": "degree"}, {"name": "Geodetic longitude", "abbreviation": "Lon", "direction": "east", "unit": "degree"}]}, "id": {"authority": "EPSG", "code": 4326}}, "conversion": {"name": "Popular Visualisation Pseudo-Mercator", "method": {"name": "Popular Visualisation Pseudo Mercator", "id": {"authority": "EPSG", "code": 1024}}, "parameters": [{"name": "Latitude of natural origin", "value": 0, "unit": "degree", "id": {"authority": "EPSG", "code": 8801}}, {"name": "Longitude of natural origin", "value": 0, "unit": "degree", "id": {"authority": "EPSG", "code": 8802}}, {"name": "False easting", "value": 0, "unit": "metre", "id": {"authority": "EPSG", "code": 8806}}, {"name": "False northing", "value": 0, "unit": "metre", "id": {"authority": "EPSG", "code": 8807}}]}, "coordinate_system": {"subtype": "Cartesian", "axis": [{"name": "Easting", "abbreviation": "X", "direction": "east", "unit": "metre"}, {"name": "Northing", "abbreviation": "Y", "direction": "north", "unit": "metre"}]}, "scope": "Web mapping and visualisation.", "area": "World between 85.06\u00b0S and 85.06\u00b0N.", "bbox": {"south_latitude": -85.06, "west_longitude": -180, "north_latitude": 85.06, "east_longitude": 180}, "id": {"authority": "EPSG", "code": 3857}}
First few rows:
id ... geometry
0 008afca9-4118-4569-86a4-e05d2049e5ff ... LINESTRING (-8237655.109 4969349.09, -8237647....
1 019954ce-599a-4f44-9509-f5df571ec8a6 ... LINESTRING (-8238414.664 4968742.88, -8238412....
2 01e21e38-aa74-4a1b-aea5-0c154bc52559 ... LINESTRING (-8237647.194 4969335.991, -8237653...
3 0241690c-de63-42c3-8049-dd993673823b ... LINESTRING (-8239417.709 4969903.63, -8239413....
4 03118a13-69c4-4dac-8677-6d9932e88536 ... LINESTRING (-8233018.341 4976811.579, -8232985...
[5 rows x 5 columns]
Geometry types: <ArrowStringArray>
['LineString']
Length: 1, dtype: str
Successfully saved to nyc_cycleways_wgs84.geoparquet
New CRS: EPSG:4326
Geometry types: <ArrowStringArray>
['LineString']
Length: 1, dtype: str
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Bash
ls -l nyc_cycleways_wgs84.geoparquet
-rw-r--r-- 1 agent agent 80922 Jun 19 01:58 nyc_cycleways_wgs84.geoparquet
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