---
title: 'Sharing, replay, heatmaps & the app'
url: 'http://www.mlat.uk/guide/sharing'
markdown: 'http://www.mlat.uk/guide/sharing.md'
date: '2026-10-22'
description: ".mlat-guide { --u: clamp(16px, 15.2px + 0.2vw, 16.8px); --g-accent: #0A74C4; --g-accent-dark: #0A5FA0; --g-bg: #ffffff; --g-bg-alt: #F5F7FA; --g-text: #14181D; --g-soft: #5B6772; --g-border: #D6DEE6; font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Text'…"
---

[User Guide](http://www.mlat.uk/guide) › Sharing, replay, heatmaps & the app

# Sharing, replay, heatmaps & the app

- [Sharing](#share)
- [What a link keeps](#links)
- [Replay](#replay)
- [Heatmap](#heatmap)
- [Install as an app](#app)

## Sharing

Choose **Share this view** in the menu, or the share icon on an object's details card on a computer. On phones and tablets this opens your device's share sheet; elsewhere the link is copied and a **Link copied** message appears.

## What a link keeps

The page's address updates as you use the map, so a refresh or a bookmark brings you straight back. A shared link opens the same:

- **Position and zoom** of the map.
- **Selected object**.
- **Search**, including a "What's nearby" pin and radius, whether **Show on the map** is on, and any **picked** results.
- **Layers** that are switched on.
- Object-list **filters**, if **Include Filters In URLs** is on in Settings.
- A **heatmap**, with its choice of aircraft or vessels and its period.

## Replay

Choose **Replay** in the menu to play back past traffic: aircraft, vessels and satellites together, on the same map. History goes back up to 30 days. A panel opens along the bottom of the screen, with the bottom bar moving above it:

- Choose the **date**, **hour** and **minute** to start from. Moving them jumps to that time.
- Press **play** (or **pause**) and set the **speed**, from real time up to 1000×.
- Select any aircraft, vessel or satellite to see its track up to that moment. The Trail History setting sets how far back the track reaches.
- Close the panel with its own **×** to return to live traffic.

![Replay panel along the bottom of the map](http://www.mlat.uk/user/pages/08.guide/07.sharing/replay.jpg)Replay: the panel along the bottom sets the date, time and speed

Aircraft and vessels are recorded at intervals, and the replay fills in the movement between recorded positions, so they glide rather than jump. Satellites are not recorded: their positions are worked out from their orbits for the time you choose, so they are accurate for any date.

## Heatmap

A heatmap shows where traffic has been, as a glow that gets brighter and warmer wherever more aircraft or vessels have passed. Choose **Heatmap** in the menu, then:

- **Show** - aircraft, vessels, or both at once. Aircraft glow blue through green and yellow to red; vessels glow purple to pale cyan.
- **Period** - the last hour, 6 hours, 24 hours, 3 days, 7 days or 30 days.
- Choose **Show heatmap**. The map opens at the same place and zoom.

![The Heatmap dialog: Show and Period](http://www.mlat.uk/user/pages/08.guide/07.sharing/heatmap-dialog.jpg)Choosing what to show and for how long

![A 24-hour heatmap of aircraft and vessels over the UK and Europe](http://www.mlat.uk/user/pages/08.guide/07.sharing/heatmap.jpg)Twenty-four hours of aircraft and vessels: the busiest routes and airports glow red

Pan and zoom as normal: the heatmap sharpens as you zoom in. A label at the top says what you are looking at and how many positions it covers, and **Exit** returns to the live map. Satellites have no heatmap, because their paths follow their orbits rather than their history.

## Install as an app

mlat.uk can be installed so it opens full screen from your home screen, like an app:

- **iPhone and iPad** - in Safari, tap Share, then **Add to Home Screen**.
- **Android** - in Chrome, tap the menu, then **Install app** or **Add to Home screen**.
- **Computer** - in Chrome or Edge, use the install icon in the address bar.

The map may also offer an **Install** prompt itself; **Not now** hides it.

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## Navigation

- Parent: [User Guide](http://www.mlat.uk/guide.md)
- Previous: [Settings](http://www.mlat.uk/guide/settings.md)
- Next: [Keyboard shortcuts](http://www.mlat.uk/guide/shortcuts.md)