MapLineDraw
Draw smooth curves on real maps.
MapLineDraw lets you sketch corridors of railway lines or roads on an interactive map using smooth spline curves, ready to share with others.
Whether you're a transit enthusiast, a city planner, or just someone who loves to visualize infrastructure, MapLineDraw is a free and open source web application designed to let you draw smooth curves on a map provided by OpenStreetMap.
What Is MapLineDraw?
MapLineDraw is a free, open source web application that lets you draw smooth spline curves directly on an interactive map (using OpenStreetMap tiles). The tool is ideal for:
- Sketching railway lines, highways, race tracks, or other paths
- Measuring real-world infrastructure curves
- Visualizing concepts for future public transport
- Sharing your ideas with others using simple, link-based projects
Typically line-drawing tools rely on connected straight segments. MapLineDraw uses cubic B-splines, which means it can represent curved lines with continuous curvature — an important feature in real-world railroad or road design.
Key Features
MapLineDraw comes with many useful features, such as the following:Interactive Spline Drawing
Click to place control points, drag them to adjust, and instantly see the resulting curve update in real time.
Cubic B-splines
Smooth spline paths of degree 3 with continuous curvature for realistic road and rail geometry.
Automatic Geometry Analysis
Calculates curve length, minimum radius, and estimated maximum speed using comfort-based acceleration limits.
Open or Closed Curves
Supports both open routes and closed loops — ideal for tracks, circuits, and circular paths.
Project Metadata
Add a project name, author, and description to document your design ideas clearly.
Download and Share
Save projects to a JSON file containing geometry and metadata, or share them via link-based URLs.
Customizable Legends
Color-coded curves editable in the JSON file help clarify and organize your visualizations.
Use Cases
Infrastructure design is no longer the exclusive domain of specialized, expensive CAD tools. With MapLineDraw, anyone can:
- Draft hypothetical rail corridors across regions
- Analyze existing road or rail curves for speed feasibility
- Trace real-world routes for measurement or export
- Sketch race track concepts, nature trails, or fantasy transit systems
It's a tool built for hobbyists, students, planners, and open data advocates.
Export and Import
While MapLineDraw does not currently export GeoJSON or KML, it allows you to download your project in a custom JSON format. This includes:
- Curve type (open or closed)
- Degree of spline
- Control point coordinates (lat/lon)
- Project metadata and legend
Because the format is clean and structured, it's easy to convert into other formats using a simple script — or fork the project to add that feature.
Open Source
MapLineDraw is fully open source under the MIT license. You can:
- View or contribute on GitHub
- Suggest features or report bugs via issues
- Fork the project and customize it to your needs
Known Limitations
MapLineDraw is not a professional-grade design tool. Its goal is simplicity, accessibility, and visual clarity — not engineering validation.
- No elevation (height) support (no tunnels or bridges yet)
- No mobile browser optimization (best used on desktop)
- No built-in export to GIS formats (yet)
Conclusion
MapLineDraw provides a simple and free drawing tool for curves on a real map. Whether you're mapping the next high-speed rail link or tracing an existing corridor for fun, it's a tool that helps ideas take shape — smoothly. Visit maplinedraw.com to start drawing.
If you like the tool or have suggestions for improvement, contribute or open an issue on GitHub.