Free Online GeoJSON PlotLineString Draw Tool
Draw smooth curved lines on a map. Click control points for smooth curve interpolation. Export as GeoJSON LineString. Free GIS curve tool.
What is PlotLineString?
PlotLineString draws a smooth curved line through control points using curve interpolation. Unlike standard Polyline with straight segments, PlotLineString generates mathematically smoothed curves between control points. It supports multiple interpolation methods (curve, bezier, bspline, straight) for different line aesthetics.
How to draw
To draw a PlotLineString, select PlotLineString mode. Click 3+ control points on the map. The line interpolates smoothly through all points. Double-click to finish. The result is a smooth curved GeoJSON LineString.
Common uses
Smooth lines are used for road design visualization, flight path plotting, trajectory analysis, natural feature mapping (rivers, contours), and any application where smooth curved lines are preferred over straight-segment polylines.
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.