geospatial-projection-selection

name	geospatial-projection-selection
description	Guidance on selecting appropriate CRS projections for geospatial distance calculations, especially EPSG:4087 for global analyses.

EPSG:4087 — World Equidistant Cylindrical

• Use case: Global distance calculations where a single consistent projection is needed
• Properties: Equidistant along meridians; distances measured in meters
• CRS string: EPSG:4087

gdf_projected = gdf.to_crs('EPSG:4087')

When to use EPSG:4087 vs other projections

Projection	Use case
EPSG:4326	Spatial containment, lat/lon storage (unprojected)
EPSG:4087	Global distance calculations in meters
Custom aeqd	Local distance calculations centered on a specific point
EPSG:3857	Web mapping (NOT for distance/area calculations)

Important notes for Pacific plate analysis

• The Pacific plate crosses the antimeridian (±180° longitude)
• Do NOT project the Pacific plate polygon for containment checks — use EPSG:4326
• Do project points and boundaries to EPSG:4087 for distance calculations
• Use make_valid() from shapely.validation on plate polygons that may have topology issues