Geospatial Buffer & Projection Lab
Leaflet + Turf.js v7.2.0
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Export GeoJSON
Presets & Location
Select Scenario Preset
San Francisco Urban Zone (Mid Latitude)
Arctic Circle (High Latitude Distortion)
Galapagos (Equatorial Zone)
Target Coordinate (Lon, Lat)
DD / DMS
Buffer Engine Parameters
Buffer Radius (
km
)
50 km
Turf Geometry Steps
32 (Coarse Speed)
64 (Standard Precision)
128 (High Precision Smooth)
Overlay Options
Show True Geodesic Buffer
Show Planar Mercator Buffer
Show Feature Bounding Box
Custom Spatial Features
Drag center marker on map to re-calculate, or draw custom features below.
Add Marker
Clear All
Import Custom GeoJSON
Projection:
Web Mercator (EPSG:3857)
Geo Engine:
Turf.js Geodesic
Buffer & Surface Analysis
TRUE GEODESIC SURFACE AREA
7,853.98 km²
Calculated via WGS84 Ellipsoid
PLANAR (WEB MERCATOR) AREA
12,410.20 km²
Apparent visual map area
MERCATOR LATITUDE DISTORTION
+58.0%
Scale factor inflates area by 1.58x at lat 37.8°
Geodesic Metrics Summary
PERIMETER / BOUNDARY CIRCUMFERENCE
314.15 km
BOUNDING BOX (WEST, SOUTH, EAST, NORTH)
-122.98, 37.32, -121.85, 38.22
Layer Legend
True Geodesic Buffer (Turf.js WGS84)
Planar Projection Distortion Buffer