Import Data Dialog Import Button

When importing a large dataset that can cause the browser prompt to kill the process, or "wait," there is no indication that that web app is busy. This is even more glaring when the browser is started without the browser hang monitor so you don't have to babysit the import. What's needed is a spinner indicating busy because it can look just like a hung process.

To make a spinner actually animate while handling heavy data, shift the file parsing off the browser's main interface thread. This can be achieved by using a feature called a Web Worker.

• The Main Thread: Handles the map UI, button clicks, and renders a smooth, spinning loading animation.

• The Web Worker Thread: Runs quietly in the background, crunching all data.

Because the work is split, the map interface never freezes, the spinner keeps turning, and the browser wouldn't even think about triggering a hang monitor.

This is a massive quality-of-life upgrade for anyone doing serious GIS or mapping work.