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": "deepseek/deepseek-v4-flash",
"base_url": "https://openrouter.ai/api/v1"
}
0:04
Let me start by examining the input file to understand its structure, CRS, and attributes before converting.
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Bash
ls /work/nyc_cycleways*
/work/nyc_cycleways_webmercator.geoparquet
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Let me first inspect the file to understand its structure, CRS, and attributes.
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Bash
cd /work && python -c "
cd /work && python -c "
import geopandas as gpd
gdf = gpd.read_file('nyc_cycleways_webmercator.geoparquet')
print('CRS:', gdf.crs)
print('Columns:', gdf.columns.tolist())
print('Shape:', gdf.shape)
print('Geometry types:', gdf.geometry.geom_type.value_counts())
print('First row:')
print(gdf.head(1).to_string())
print('---')
print(gdf.dtypes)
"
Traceback (most recent call last):
File "<string>", line 3, 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'.
0:14
Let me check the actual filename more carefully.
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Bash
ls -la /work/
total 88 drwxr-xr-x 1 agent agent 72 Jun 9 06:49 . drwxr-xr-x 1 root root 14 Jun 9 06:49 .. -rw-r--r-- 1 agent agent 86058 Jun 9 06:49 nyc_cycleways_webmercator.geoparquet
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The file is there but pyogrio can't read it. Let me try with DuckDB or with pyarrow/geopandas via the parquet engine.
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Bash
cd /work && python -c "
cd /work && python -c "
import geopandas as gpd
gdf = gpd.read_parquet('nyc_cycleways_webmercator.geoparquet')
print('CRS:', gdf.crs)
print('Columns:', gdf.columns.tolist())
print('Shape:', gdf.shape)
print('Geometry types:', gdf.geometry.geom_type.value_counts())
print('First row:')
print(gdf.head(1).to_string())
print('---')
print(gdf.dtypes)
"
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}}
Columns: ['id', 'class', 'subclass', 'name', 'geometry']
Shape: (272, 5)
Geometry types: LineString 272
Name: count, dtype: int64
First row:
id class subclass name geometry
0 008afca9-4118-4569-86a4-e05d2049e5ff cycleway Dover Street LINESTRING (-8237655.109 4969349.09, -8237647.194 4969335.991)
---
id str
class str
subclass str
name str
geometry geometry
dtype: object
0:28
The data is in EPSG:3857 (Web Mercator). I need to: 1. Convert to WGS 84 (EPSG:4326) which gives lat/lon in degrees 2. Keep all attributes the same 3. Ensure each geometry stays a plain LineString (not MultiLineString) - since they're already LineStrings, this should be okay 4. Write as GeoParquet with `id` as the key 5. Output file: `nyc_cycleways_wgs84.geoparquet` Let me write and run the script.
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Write
/work/solve.py
content · 31 lines · py
import geopandas as gpd
# Read the Web Mercator GeoParquet
gdf = gpd.read_parquet("/work/nyc_cycleways_webmercator.geoparquet")
print(f"Input CRS: {gdf.crs}")
print(f"Input shape: {gdf.shape}")
print(f"Geometry types: {gdf.geometry.geom_type.value_counts().to_dict()}")
# Verify all geometries are LineString (not MultiLineString)
assert (gdf.geometry.geom_type == "LineString").all(), "Not all geometries are LineString!"
# Reproject to WGS 84 (EPSG:4326) — plain lat/lon
gdf_wgs84 = gdf.to_crs("EPSG:4326")
print(f"Output CRS: {gdf_wgs84.crs}")
print(f"Output shape: {gdf_wgs84.shape}")
# Confirm geometry types preserved
print(f"Output geometry types: {gdf_wgs84.geometry.geom_type.value_counts().to_dict()}")
# Verify coordinates are in degrees (range ~ -180..180)
bounds = gdf_wgs84.geometry.total_bounds
print(f"Bounds (minx, miny, maxx, maxy): {bounds}")
# Write GeoParquet with 'id' as the row key
gdf_wgs84.to_parquet(
"/work/nyc_cycleways_wgs84.geoparquet",
index=False,
row_group_size=100,
version="2.4",
)
print("Done: wrote nyc_cycleways_wgs84.geoparquet")Wrote /work/solve.py (1091 chars).
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Let me run the script.
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Bash
cd /work && python solve.py
Input 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}}
Input shape: (272, 5)
Geometry types: {'LineString': 272}
Output CRS: EPSG:4326
Output shape: (272, 5)
Output geometry types: {'LineString': 272}
Bounds (minx, miny, maxx, maxy): [-74.0177637 40.7004314 -73.931735 40.788778 ]
Done: wrote nyc_cycleways_wgs84.geoparquet
0:37
Let me verify the output file exists and the bounds make sense (they do — NYC is around lat 40.7, lon -74.0).
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Bash
ls -la /work/nyc_cycleways_wgs84.geoparquet
-rw-r--r-- 1 agent agent 93422 Jun 9 06:50 /work/nyc_cycleways_wgs84.geoparquet
0:42
Let me verify the output is correct by reading it back and checking a few things: 1. CRS is EPSG:4326 (lat/lon) 2. All geometries are LineString (not MultiLineString) 3. `id` column is present 4. Coordinates are in degrees (bounds ~ -74 to -73, 40 to 41 for NYC) 5. All original columns are preserved
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Bash
cd /work && python -c "
cd /work && python -c "
import geopandas as gpd
gdf = gpd.read_parquet('nyc_cycleways_wgs84.geoparquet')
print('CRS:', gdf.crs)
print('Columns:', gdf.columns.tolist())
print('Shape:', gdf.shape)
print('Geometry types:', gdf.geometry.geom_type.value_counts().to_dict())
print('Bounds:', gdf.geometry.total_bounds)
print('Sample row:')
print(gdf.head(2).to_string())
"
CRS: {"$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "GeographicCRS", "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"}]}, "scope": "Horizontal component of 3D system.", "area": "World.", "bbox": {"south_latitude": -90, "west_longitude": -180, "north_latitude": 90, "east_longitude": 180}, "id": {"authority": "EPSG", "code": 4326}}
Columns: ['id', 'class', 'subclass', 'name', 'geometry']
Shape: (272, 5)
Geometry types: {'LineString': 272}
Bounds: [-74.0177637 40.7004314 -73.931735 40.788778 ]
Sample row:
id class subclass name geometry
0 008afca9-4118-4569-86a4-e05d2049e5ff cycleway Dover Street LINESTRING (-74.00011 40.70788, -74.00004 40.70779)
1 019954ce-599a-4f44-9509-f5df571ec8a6 cycleway East River Greenway LINESTRING (-74.00694 40.70375, -74.00692 40.70376, -74.00629 40.70416, -74.00612 40.70427, -74.00477 40.70514, -74.0046 40.70525, -74.00442 40.70537, -74.00387 40.70572, -74.00375 40.70579, -74.00369 40.70582, -74.0036 40.70585, -74.00352 40.70588, -74.00346 40.70591, -74.00339 40.70594, -74.00312 40.70612, -74.0031 40.70612, -74.00305 40.70616, -74.00302 40.70618, -74.00298 40.7062, -74.00294 40.70622, -74.00255 40.70645, -74.00231 40.70659, -74.00227 40.70662, -74.00224 40.70663, -74.00221 40.70665)
0:52
Everything looks good. Let me verify all requirements: 1. ✅ Coordinates converted from Web Mercator (EPSG:3857) to plain lat/lon (EPSG:4326) 2. ✅ Attributes left alone (id, class, subclass, name all preserved) 3. ✅ Each geometry stays a plain LineString (272 LineStrings, no MultiLineStrings) 4. ✅ Written as GeoParquet to `nyc_cycleways_wgs84.geoparquet` 5. ✅ `id` column remains as the key 6. ✅ Coordinate magnitudes are in degree range (~-74, ~40) which is correct for NYC 7. ✅ File exists on disk
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