evo-geospatial-antimeridian-plates

evo-geospatial-antimeridian-plates

Handles loading PB2002 tectonic plate polygon and boundary GeoJSON files, filtering by plate code, and normalizing coordinates across the antimeridian to 0-360 range.

Key Concepts

Antimeridian Problem

The Pacific plate spans the 180°/-180° antimeridian. Standard WGS84 coordinates wrap at this boundary, causing catastrophic topological artifacts when projecting. Solution: shift all negative longitudes by +360 to create a continuous 0°-360° space.

PB2002 Data Model

• Plates file (PB2002_plates.json): Contains Polygon/MultiPolygon geometries. Pacific plate identified by Code == 'PA'.
• Boundaries file (PB2002_boundaries.json): Contains LineString geometries. Each segment has PlateA and PlateB properties. Pacific boundaries are where PlateA == 'PA' OR PlateB == 'PA'.

Coordinate Handling

• Use shapely.transform(geometry, func) (Shapely 2.0 array interface) - NOT shapely.ops.transform
• Use unary_union() - NOT deprecated cascaded_union
• After shifting, use set_crs(epsg=4326, allow_override=True) to assign CRS metadata
• Use to_crs(epsg=3832) for Pacific-centric metric projection (PDC Mercator, central meridian 150°E)

Functions

shift_antimeridian_coords(coords)

Shapely 2.0 transform callback. Takes (N,2) or (N,3) ndarray, shifts longitude < 0 by +360.

load_plate_polygon(plates_geojson_path, target_plate_code='PA')

Loads PB2002 plates, filters by code, shifts to 0-360, returns GeoDataFrame with CRS=EPSG:4326.

load_plate_boundaries(boundaries_geojson_path, target_plate_code='PA')

Loads PB2002 boundaries, filters by PlateA/PlateB, shifts to 0-360, returns unified MultiLineString geometry.

Usage

import sys
sys.path.insert(0, '/app/environment/skills/evo-geospatial-antimeridian-plates/scripts')
from utils import shift_antimeridian_coords, load_plate_polygon, load_plate_boundaries

# Load Pacific plate polygon (shifted to 0-360)
pacific_plate_gdf = load_plate_polygon('/root/PB2002_plates.json', 'PA')

# Load Pacific plate boundary as unified geometry (shifted to 0-360)
pacific_boundary = load_plate_boundaries('/root/PB2002_boundaries.json', 'PA')