Using the maps and pins on DetectID

The Map is one of DetectID’s primary surfaces — it sits in the top nav next to Identify, Collection, and Rallies. Open it at /mapand you get a live OpenStreetMap base layer with every find you’ve plotted, a heat-map density view, and (on Basic) a live session-tracking panel that records your route as you sweep. This walkthrough covers the Map at every tier — what Free unlocks, what Basic adds, and what Premium layers on top — plus the privacy model that makes any of this safe to use.

Where to find it

Open the app and look at the top nav. Map sits between Collection and Rallies. Tap it (or go directly to /map) and the map renders. On mobile the nav collapses into the hamburger but the Map item is always in the first row — we treat it as a primary surface, not a secondary “Tools” thing.

The map opens centred on the UK by default. If you’ve already granted location permission, it’ll centre on you instead. The heat-map density layer is on by default; the pin layer toggles on as soon as you have a saved find with a plotted location.

The Free experience

Every signed-in account — including Free — can open the Map. You don’t need to be paying to see how it works, and we deliberately keep the entry path low-friction so people understand what the Basic upgrade actually unlocks.

What you can do on Free

• Open the Map page— the full UI loads, you can pan and zoom anywhere.
• “📍 Show my location”— a one-tap button drops a pin at your current GPS. Useful for checking the device fix is sensible before you head out, and for showing friends where you’re standing.
• Heat map density visualisation— the density layer renders for whatever pinned finds you have. On Free, finds aren’t saved permanently to a collection, so the heat map will only show anything if you’ve pinned something in the current session. It’s mostly empty until you upgrade.
• Five privacy precision levels— the same precision controls apply on every tier (covered in detail below).

The Basic experience — live session tracking

Upgrading to Basic (£1.99/month) is where the Map starts earning its keep. The headline addition is live session tracking: while a session is running, DetectID auto-records your position every 30 seconds and draws a trail, and any coin you identify during the session auto-pins at your current GPS — no manual location-picking needed.

Starting a session

1. Open /map. On Basic and Premium accounts, a Start session button is visible in the right-hand panel (or as a floating action button on mobile).
2. Tap Start session. The browser asks for location permission — grant it. You only do this once per device.
3. Add a label if you want (“Old Plough Lane”, “West field, north end”). Optional but helpful later.
4. The trail starts building. Every 30 seconds your position is appended to the session route and the map redraws.

Auto-pin during the session

With a session live, every coin you identify on /identifyauto-pins at your current GPS position when you save it. You don’t need to expand the Location accordion or drop a pin yourself — DetectID reads the active session and uses the latest fix. The find is automatically tagged to that session too, so reviewing the session later shows every find from that outing in one place.

Ending a session

Tap End sessionwhen you’re done. The session is saved to your Session log with start time, end time, total distance, duration, and a count of finds identified. The trail itself is added to your permanent heat-map, so over time your most-worked ground shows up as the hottest patches.

Reviewing past sessions

The Session log panel lists every session you’ve run, most recent first. Tap one to see its route on the map, its find list, and a short summary. The full pattern is covered in the dedicated walkthrough at Detecting sessions.

The rest of the Basic map kit

On top of live sessions, Basic also gives you:

• Permanent saved finds. Free is session-only; Basic saves every find to your collection forever, which is what makes the heat map worth having.
• Per-find privacy precision toggle.Override your account default on individual finds — sensitive permission gets hidden, your back garden gets exact, the rally field gets 1 km.
• Find pins coloured by period. Roman bronze, Anglo-Saxon medium, Medieval gold, Post-medieval green, Modern grey. Scan the map and the era distribution jumps out.
• Privacy circles around blurred finds. Any find pinned at 1 km or 10 km precision draws a translucent circle showing the implied radius, so you can see at a glance how vague each pin really is.

The Premium experience — map intelligence

Premium (£3.99/month) keeps everything from Basic and layers on the research tools that turn the map from “where I’ve been” into “where I should go next”. The Premium-only layers are toggled from the same control strip at the top of the map.

What Premium adds

• Historic OS map overlay (1840s–1960s). The National Library of Scotland’s Ordnance Survey series, layered over the modern base map with a swipe-slider. Lost field boundaries, deserted medieval villages, long-vanished farmsteads — the kind of context that turns a featureless modern field into a research target. See Using the historic OS overlay.
• Roman roads overlay.The Iter network and known minor routes, overlaid on the map. Toggle it on while looking at a permission to see whether you’re near a known corridor. Walkthrough: Using the Roman roads overlay.
• Soil & geology overlay. Clay, chalk, sand and other surface geologies, field-by-field. Useful for predicting how a piece of ground will read on the detector and for understanding why some permissions go quiet after rain.
• Nearby PAS finds within 5 km.Every public record from the Portable Antiquities Scheme that falls within 5 km of your permissions. See what’s already been recorded near your patch — covered in The PAS nearby finds layer.
• Filter by ruler / denomination / value range. Show only Edward I pennies, or only finds worth more than £50, or only Roman bronzes. Useful for spotting clusters that aren’t obvious in the unfiltered view.
• Productivity stats per site. Which permission has yielded the most finds? Highest-value finds? Most identifications per hour? The map sidebar ranks your permissions on each.
• KML export. Pull your pins out as KML for Garmin handheld GPS units or Google Earth. KML and CSV export covers the full workflow.
• CSV export. Same finds, tabular, suitable for Excel or long-term archival.
• Personal find-hotspot ranking.An automatic ranking of the warmest patches on your own heat map, useful when you’re planning where to start a session.

The privacy model

Every find you save has a precision setting attached. That setting controls what gets stored, what other users see if you share the find, and what gets exported.

1. Exact— pin sits at the actual coordinates. Visible only to you. Even if you mark the find public, the pin is degraded before display.
2. 1 km grid— pin snaps to the centre of the surrounding 1 km square. A translucent privacy circle shows the implied radius. Recommended default.
3. 10 km grid— pin snaps to a 10 km square. Rough region without giving away the permission.
4. County only— no map dot. The find is tagged with the county and counts in by-region statistics, but doesn’t appear on any map.
5. Hidden— completely off the map. For sensitive permissions you don’t want plotted at all.

Public sharing respects your precision. If you mark a find public at 1 km, every viewer sees it at 1 km. We never sharpen on share. Exact-precision finds never appear publicly at all.

Best practices for live sessions

Battery

Live sessions ping GPS every 30 seconds and write a small record locally. The drain is modest, but a long session on a cold day will still cost meaningful battery. Recommendations:

• Where possible, put the phone in airplane mode with GPS still on. GPS is a passive receiver — it works without cellular or Wi-Fi — and airplane mode stops the radios from burning power searching for towers in rural ground.
• Screen-off is fine.The session keeps recording with the screen locked; you don’t need to keep the app foregrounded.
• Bring a power bank for sessions longer than three or four hours, especially in winter.

GPS accuracy

Outdoors with a clear sky, a phone fix usually settles to within 5–10 m after 15–30 seconds of standing still. Under tree cover or in deep valleys it can drift to 30 m or more. The session trail logs whatever the device reports; for precision-critical pins (finds you’ll permanently save) wait a few seconds before tapping Save on the identify page.

What happens if signal drops

Mobile signal isn’t needed for GPS, and it isn’t needed to keep the session running either. While you’re offline, position updates and any finds you save are buffered in localStorageon your phone. When you next get signal, the buffer flushes to the server and your session and finds appear in your collection. You don’t need to do anything — just keep detecting.

Changing the default precision

New finds inherit your account default if you don’t pick something different. Change it at /settings/profile under Default precision. 1 km is the right choice for most people — granular enough to be useful, vague enough to protect a permission if a find ever leaks.

Common questions

Can I move a pin after uploading?

Yes. Open the find from your collection, edit the location, and save. Both the pin and the precision can be changed at any time.

Does auto-pin override my precision setting?

No. Auto-pin places the find at your GPS coordinates and then applies your account’s default precision to it. If your default is 1 km, the auto-pinned find is stored at 1 km precision, not exact. You can override per find on the find detail page.

Can I delete a session?

Yes — from the Session log, open the session and tap Delete session. Deleting the session removes its trail from your heat map and removes the session tag from any finds it had attached, but it doesn’t delete the finds themselves.

Why don’t I see the “Show my location” button?

It only appears once the browser has been granted location permission. If you blocked the prompt or are in a private/ incognito window that disables geolocation, the button is hidden. Re-enable location permission in your browser settings, refresh, and it’ll reappear.

Next steps

• Privacy details in full: Privacy and location precision.
• Tagging finds to a permission: Detecting sessions.
• Premium: Using the historic OS overlay.
• Premium: Using the Roman roads overlay.
• Premium: The PAS nearby finds layer.
• Premium: KML and CSV export.