What is GeoPandas?
GeoPandas is a powerful Python library that extends pandas to handle geographic data. It combines:
- Data manipulation tools of pandas
- Geospatial functionality of libraries like
shapelyandfiona
Key benefits:
- Efficient handling of geospatial data
- Useful for data science and visualization projects
You can it with
pip install geopandas
And import it with:
import geopandas as gpdReading Geospatial Data
GeoPandas excels at reading various geospatial file formats:
- Shapefiles
- GeoJSON
- GeoPackage
Let's read a GeoJSON file of world country boundaries:
Main functions used:
gpd.read_file(): Reads geospatial data from a filegpd.datasets.get_path(): Provides path to built-in datasets
world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
world.head()/var/folders/m2/jfzxyg4s0xz3jyw5f94r7tcm0000gn/T/ipykernel_81203/913829029.py:1: FutureWarning: The geopandas.dataset module is deprecated and will be removed in GeoPandas 1.0. You can get the original 'naturalearth_lowres' data from https://www.naturalearthdata.com/downloads/110m-cultural-vectors/.
world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
| pop_est | continent | name | iso_a3 | gdp_md_est | geometry | |
|---|---|---|---|---|---|---|
| 0 | 889953.0 | Oceania | Fiji | FJI | 5496 | MULTIPOLYGON (((180.00000 -16.06713, 180.00000... |
| 1 | 58005463.0 | Africa | Tanzania | TZA | 63177 | POLYGON ((33.90371 -0.95000, 34.07262 -1.05982... |
| 2 | 603253.0 | Africa | W. Sahara | ESH | 907 | POLYGON ((-8.66559 27.65643, -8.66512 27.58948... |
| 3 | 37589262.0 | North America | Canada | CAN | 1736425 | MULTIPOLYGON (((-122.84000 49.00000, -122.9742... |
| 4 | 328239523.0 | North America | United States of America | USA | 21433226 | MULTIPOLYGON (((-122.84000 49.00000, -120.0000... |
Basic Data Manipulation
GeoPandas allows you to manipulate geometric data using familiar pandas operations:
- Filtering
- Grouping
- Aggregating
Example: Filter to show only European countries:
europe = world[world['continent'] == 'Europe']
europe.head()| pop_est | continent | name | iso_a3 | gdp_md_est | geometry | |
|---|---|---|---|---|---|---|
| 18 | 144373535.0 | Europe | Russia | RUS | 1699876 | MULTIPOLYGON (((180.00000 71.51571, 180.00000 ... |
| 21 | 5347896.0 | Europe | Norway | NOR | 403336 | MULTIPOLYGON (((15.14282 79.67431, 15.52255 80... |
| 43 | 67059887.0 | Europe | France | FRA | 2715518 | MULTIPOLYGON (((-51.65780 4.15623, -52.24934 3... |
| 110 | 10285453.0 | Europe | Sweden | SWE | 530883 | POLYGON ((11.02737 58.85615, 11.46827 59.43239... |
| 111 | 9466856.0 | Europe | Belarus | BLR | 63080 | POLYGON ((28.17671 56.16913, 29.22951 55.91834... |
Key concept: GeoDataFrames behave like regular pandas DataFrames but preserve geometric data.
Visualizing Geospatial Data
GeoPandas leverages matplotlib for quick and easy map creation:
.plot(): Creates a plot of the GeoDataFramecolumn: Specifies which data to use for coloringcmap: Sets the color schemelegend: Adds a color barfigsize: Sets the figure size
ax = europe.plot(column='pop_est', cmap='YlOrRd', legend=True,
legend_kwds={'label': 'Population', 'orientation': 'horizontal'},
figsize=(12, 8))
ax.set_xlim(-20, 180)
ax.set_ylim(30, 90)(30.0, 90.0)
Geospatial Operations
GeoPandas enables various geospatial operations, crucial for advanced analysis and visualizations:
.geometry.centroid: Calculates the geometric center of each shape.plot(): Can be used multiple times on the same axis (ax) to overlay different geometries
# Calculate centroids
europe['centroid'] = europe.geometry.centroid
# Plot countries and centroids
ax = europe.plot(figsize=(12, 8))
europe.centroid.plot(ax=ax, color='black', markersize=10)
ax.set_xlim(-20, 180)
ax.set_ylim(30, 90)/var/folders/m2/jfzxyg4s0xz3jyw5f94r7tcm0000gn/T/ipykernel_81203/2886758021.py:2: UserWarning: Geometry is in a geographic CRS. Results from 'centroid' are likely incorrect. Use 'GeoSeries.to_crs()' to re-project geometries to a projected CRS before this operation.
europe['centroid'] = europe.geometry.centroid
/Users/josephbarbier/Desktop/The-Python-Graph-Gallery/venv/lib/python3.10/site-packages/geopandas/geodataframe.py:1525: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy
super().__setitem__(key, value)
/var/folders/m2/jfzxyg4s0xz3jyw5f94r7tcm0000gn/T/ipykernel_81203/2886758021.py:6: UserWarning: Geometry is in a geographic CRS. Results from 'centroid' are likely incorrect. Use 'GeoSeries.to_crs()' to re-project geometries to a projected CRS before this operation.
europe.centroid.plot(ax=ax, color='black', markersize=10)
(30.0, 90.0)
Going further
TLDR: geopandas allows to
- Perform spatial analysis
- Create multi-layered visualizations
Remember, GeoPandas integrates well with other Python geospatial libraries:
cartopyfor advanced mapping- folium for interactive web maps
These examples provide a foundation, but GeoPandas offers much more:
- Spatial joins
- Coordinate reference system operations
- Complex geospatial analyses
As you explore further, you'll discover its full potential for geospatial data visualization and analysis.
