mirror of
https://github.com/hwchase17/langchain
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70 lines
2.3 KiB
Python
70 lines
2.3 KiB
Python
from typing import Any, Iterator
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from langchain_core.documents import Document
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from langchain_community.document_loaders.base import BaseLoader
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class GeoDataFrameLoader(BaseLoader):
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"""Load `geopandas` Dataframe."""
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def __init__(self, data_frame: Any, page_content_column: str = "geometry"):
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"""Initialize with geopandas Dataframe.
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Args:
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data_frame: geopandas DataFrame object.
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page_content_column: Name of the column containing the page content.
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Defaults to "geometry".
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"""
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try:
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import geopandas as gpd
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except ImportError:
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raise ImportError(
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"geopandas package not found, please install it with "
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"`pip install geopandas`"
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)
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if not isinstance(data_frame, gpd.GeoDataFrame):
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raise ValueError(
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f"Expected data_frame to be a gpd.GeoDataFrame, got {type(data_frame)}"
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)
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if page_content_column not in data_frame.columns:
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raise ValueError(
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f"Expected data_frame to have a column named {page_content_column}"
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)
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if not isinstance(data_frame[page_content_column], gpd.GeoSeries):
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raise ValueError(
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f"Expected data_frame[{page_content_column}] to be a GeoSeries"
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)
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self.data_frame = data_frame
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self.page_content_column = page_content_column
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def lazy_load(self) -> Iterator[Document]:
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"""Lazy load records from dataframe."""
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# assumes all geometries in GeoSeries are same CRS and Geom Type
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crs_str = self.data_frame.crs.to_string() if self.data_frame.crs else None
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geometry_type = self.data_frame.geometry.geom_type.iloc[0]
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for _, row in self.data_frame.iterrows():
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geom = row[self.page_content_column]
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xmin, ymin, xmax, ymax = geom.bounds
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metadata = row.to_dict()
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metadata["crs"] = crs_str
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metadata["geometry_type"] = geometry_type
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metadata["xmin"] = xmin
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metadata["ymin"] = ymin
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metadata["xmax"] = xmax
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metadata["ymax"] = ymax
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metadata.pop(self.page_content_column)
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# using WKT instead of str() to help GIS system interoperability
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yield Document(page_content=geom.wkt, metadata=metadata)
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