spatial-filtering

name	spatial-filtering
description	Methods for filtering GeoDataFrames based on spatial relationships like containment and intersection.

Spatial Filtering

Overview

Spatial filtering allows you to select features based on their location relative to other features.

Point-in-Polygon

To find points that lie inside a specific polygon:

# Assuming gdf_points and gdf_polygons are GeoDataFrames
# 1. Get a specific polygon geometry
pacific_poly = gdf_polygons[gdf_polygons['Code'] == 'PA'].geometry.unary_union

# 2. Filter points
points_in_pacific = gdf_points[gdf_points.within(pacific_poly)]

Spatial Joins

Alternatively, use sjoin for batch processing:

joined = gpd.sjoin(gdf_points, gdf_polygons, predicate='within')

Attribute-based Spatial Selection

Often you need to combine attribute filters with spatial operations:

# Find boundaries associated with the Pacific plate (PA)
pacific_boundaries = gdf_boundaries[
    (gdf_boundaries['PlateA'] == 'PA') | (gdf_boundaries['PlateB'] == 'PA')
]