Why your map loads the way it does

Open a large site on the 2D Map, on the 3D Model or as a tiled point cloud and you’ll notice the same thing every time: the site appears almost at once, looking a little soft, and then sharpens where you’re looking. That is deliberate, not a glitch. Here is what is happening underneath, and how to work with it.

The short version

Those views are far too big to hand you in one piece, so we don’t. The viewer cuts them into thousands of small tiles and streams them to your browser as you need them — coarse ones first, so there is something on screen to get your bearings with, then finer ones for whatever is actually in front of you. Nothing installs, and nothing has to finish arriving before you can start looking.

Views that stream, and views that don’t

• Views that stream in tiles include the 2D Map, the 3D Model, and point clouds that were processed into tiles.
• Views that arrive as one file include the 3D Mesh and a point cloud that wasn’t cut into tiles — sometimes after a lighter preview that shows first. Once the full file has loaded there is no finer version on the way, so these don’t sharpen as you settle.
• The Flyover is a video, and plays like any other.

Everything below is about the views that stream.

Coarse first, then fine

In a view that streams, every part of your site exists at several levels of detail, from a rough version that arrives almost immediately to the full one.

• The rough pass lands first. The whole property shows up straight away — soft, but complete — so you can find the corner you care about.
• Finer tiles replace it where you are looking. The viewer works out what is filling your screen, asks for sharper tiles for those spots, and swaps them in as they arrive.
• Off-screen stays cheap. The far side of the property, while you are zoomed into one corner, stays at its rough level until you go there.

That is why the picture seems to develop rather than simply appear. It is also why a big property behaves much like a small one at the start: you are never waiting on the whole thing, only on the piece in front of you.

Why detail arrives when you stop moving

While you are panning, orbiting or flying, what fills your screen changes many times a second — and every change is a fresh set of tiles to fetch. The viewer keeps up by letting the picture stay a little soft while you are in motion, then catching up the moment you settle.

So the single most useful habit in the whole viewer: land on the view you want, then pause. The sharpest version of any spot is the one you stopped on.

Your device sets its own budget

Phones, tablets and laptops have very different amounts of memory to spend, and running out of it is what makes a browser tab go blank. So streamed 3D views, such as the 3D Model and tiled point clouds, do not use one setting for everybody.

• They measure the device they are running on and give their tile cache a memory budget to match. A laptop, a tablet and a phone each get their own.
• That budget is not fixed on the 3D Model. There it grows while the device is coping and the view is asking for more, and it pulls back when the device shows signs of strain — then remembers what it learned, so your next visit starts better informed.
• What you have already loaded is kept, up to that budget. That is why returning to a spot you have already visited comes up quicker than the first look did.

The goal is that every device gets a setting it can actually hold — not that every device behaves the same. A newer laptop will always have more room to spend than a phone, and the viewer’s job is to stay stable and usable on both.

How to get the best out of it

• Pause after you move. A moment of stillness is usually the difference between soft and sharp.
• Zoom in rather than out. Close in on one area and the viewer spends everything it has on that area. Pull back to take in the whole property and the same budget is spread across far more ground, so it stays coarser by design.
• The first look is what wants a good connection. Wi-Fi or strong cellular for the opening moments on a large site; after that you are mostly working from what is already on the device.
• Close other heavy tabs. Every open tab competes for the same memory and the same graphics chip.
• Let the loading screen finish before you fly. Most of the stutter people notice comes from moving hard while the very first tiles are still landing.

Why not just download the file instead?

We could hand you the entire scan as one file and let your machine open it. For big views like the map, the 3D Model and tiled point clouds, we don’t, because it is a worse deal in almost every way:

• You would wait for all of it before seeing any of it — including the parts you were never going to look at.
• It would have to fit in your device’s memory all at once, which is exactly the thing a phone or tablet cannot do with a large scan.
• You would need software to open it, and so would everyone you shared it with.
• It goes stale. The moment we re-fly the site, your copy is a copy of the old one; a link always shows the current flight.

Streaming gets you the opposite: a link that opens in a browser, works on the device in your pocket, and is always current. And when you genuinely do want the underlying data — for your own GIS, or to keep on file — the downloads are still there on your project page. Streaming is how we show it to you, not a substitute for handing it over.

We tune this against real devices

None of this is theory. The loading behaviour, the memory budgets and the way detail gets prioritised were measured on actual phones, tablets and computers — specific devices, on specific builds — and are measured again when we run a new round of device testing, rather than set once and assumed. What a particular device can do is a question we answer by putting the viewer on it.

If yours struggles, we would genuinely like to hear about it: tell us which device and what you saw. Which devices work with your maps? records what has been tested so far.