Free Online GeoJSON ClosedCurve Draw Tool
Draw closed smooth curves on a map. Click control points to define a smooth curved area shape, double-click to finish. Export as GeoJSON. Free GIS curve tool.
What is ClosedCurve?
ClosedCurve creates a smooth closed curve polygon through interpolation of control points. Unlike standard Polygon with straight edges, ClosedCurve generates a mathematically smooth curve passing through all clicked vertices. It produces organic, flowing shapes ideal for natural boundaries, survey areas, and aesthetic map regions.
How to draw
To draw a ClosedCurve, select ClosedCurve mode. Click 3+ control points on the map. The curve interpolates smoothly through all points. Double-click to close and finish. The resulting shape is a GeoJSON Polygon with interpolated vertices forming the smooth curve.
Common uses
Closed curves are used for natural boundary delineation, environmental survey areas, wildlife habitat zones, geological feature mapping, and any application requiring smooth, organic area shapes.
GeoJSON output
Each geometry is converted to standard GeoJSON (RFC 7946) format with WGS84 coordinates. Copy or download the output for use in any GIS or mapping application.
All geometry types
This tool supports all 12 geometry types: Point, Polyline, Polygon, Freehand, StraightArrow, DiagonalArrow, DoveTailArrow, DoubleArrow, ClosedCurve, Sector, GatheringPlace, and PlotLineString.
Privacy
All drawing and GeoJSON generation happens entirely in your browser. No data is sent to any server. Your geographic data stays on your device.