Geopandas

Getting Started with GeoPandas

References:

Installation¶

conda create -n geo python=3.8
conda activate geo
conda install geopandas
conda install nclpy matplotlib descartes -c conda-forge

Import libraries¶

In [2]:

import nclpy
import geopandas as gpd

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-2-cffb4194e449> in <module>
      1 import nclpy
----> 2 import geopandas as gpd

ModuleNotFoundError: No module named 'geopandas'

Reading files¶

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url = "https://raw.githubusercontent.com/giswqs/nclpy/main/examples/data/nyc_neighborhoods.geojson"

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gdf = gpd.read_file(url)

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gdf

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gdf.crs

Writing files¶

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gdf.to_file("data/nyc_streets.geojson", driver="GeoJSON")

Measuring area¶

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gdf = gdf.set_index("NAME")

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gdf["area"] = gdf.area
gdf["area"]

Getting polygon bounary¶

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gdf['boundary'] = gdf.boundary
gdf['boundary']

Getting polygon centroid¶

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gdf['centroid'] = gdf.centroid
gdf['centroid']

Making maps¶

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gdf.plot()

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gdf.plot("area", legend=True, figsize=(10, 8))

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gdf = gdf.set_geometry("centroid")
gdf.plot("area", legend=True,figsize=(10, 8))

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ax = gdf["geometry"].plot(figsize=(10, 8))
gdf["centroid"].plot(ax=ax, color="black")

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gdf = gdf.set_geometry("geometry")

Reprojecting data¶

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url = "https://raw.githubusercontent.com/giswqs/nclpy/main/examples/data/nyc_neighborhoods.geojson"

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gdf = gpd.read_file(url)

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gdf_crs = gdf.to_crs(epsg="4326")

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gdf_crs

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geojson = gdf_crs.__geo_interface__

Displaying data on an interative map¶

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m = nclpy.Map(center=[40.7341, -73.9113], zoom=10)
m

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style = {
    "stroke": True,
    "color": "#000000",
    "weight": 2,
    "opacity": 1,
    "fill": True,
    "fillColor": "#0000ff",
    "fillOpacity": 0.4,
}

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m.add_geojson(geojson, style=style, layer_name="nyc neighborhoods")

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url2 = "https://github.com/giswqs/nclpy/raw/main/examples/data/nyc_subway_stations.zip"

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gdf_subway = gpd.read_file(url2)

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gdf_subway_crs = gdf_subway.to_crs(epsg="4326")

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subway_geojson = gdf_subway_crs.__geo_interface__

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m.add_geojson(subway_geojson, layer_name="nyc subway stations")

Last update: 2021-05-03