Range Session Explanation

Range Session is a web app that golfers use to analyze data from launch monitors—the machines that measure things like ball speed, spin rate, and landing distance during practice. You upload a CSV file (or several) from your monitor, and the app instantly creates charts, tables, and 3D visualizations to help you understand your swing patterns. Think of it like turning raw spreadsheet numbers into a dashboard that tells a story about your performance.

The app works by reading whatever columns your launch monitor exported—carry distance, ball speed, spin axis, launch angle, and so on—and automatically building views around that data. You can filter shots by how far they went, whether they curved left or right, or which club you used. The app shows your shots as a scatter plot (bird's-eye view of where the ball landed), a distance-vs-spin chart with a trend line, a 3D flight path animation, and a detailed shot-by-shot table. There's also a summary strip at the top that updates live as you filter, showing your average carry, longest shot, spin rate, and lateral consistency. If you don't have your own data, the app loads with sample data built in, so you can see how everything works immediately.

Who uses this? Any golfer with a launch monitor at a range or indoor facility—from casual players tracking improvement to serious amateurs and coaches analyzing student swings. If you're trying to figure out whether your spin is too high, whether you're missing consistently left, or how your ball speed compares to a benchmark for your skill level, this tool does that without needing to import into Excel or write formulas. The app recognizes common column names from most monitor brands (Trackman, Foresight, etc.), handles multiple files in one session, and can guess which club you used based on the filename.

The project is notably simple in architecture: it's a single static HTML file with no build step, no backend server, and no npm dependencies beyond what Bun provides. You can run it locally by serving the HTML through Bun, or open it directly in a browser. There's also a live version hosted on GitHub Pages that you can use right now without downloading anything. The flexibility to work with whatever columns your monitor provides—and the 3D visualization that sketches flight paths from carry distance and lateral movement—are the main ways it stands apart from generic spreadsheet analysis.