> For the complete documentation index, see [llms.txt](https://codifi-fdm.gitbook.io/codifi-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://codifi-fdm.gitbook.io/codifi-docs/mobile-app/mapping-locations/map-overlays.md).

# Map Overlays

**Map overlays** are reference layers your project manager loads into the Project on the web — things like aerial imagery, parcel boundaries, prior survey coverage, agency-provided GIS data, or infrastructure. They render *below* your Codifi Records on the map, so your work always sits visually on top of the reference layers.

Overlays sync to your iPad with the Project, so they're available offline.

***

## How overlays get to your iPad

You don't manually download overlays. When your PM adds overlays to a Project on the web, the next time your iPad syncs the Project, the overlays come with it — styled, ready to display, and cached offline.

To check what overlays a Project has, open the **layers sheet** from the right edge of the map screen. You'll see a list of every overlay the Project includes, each with a visibility toggle.

> **Screenshot placeholder:** *The layers sheet open on the map screen, showing toggles for each map overlay.*

***

## Showing and hiding overlays

In the layers sheet, toggle individual overlays on or off:

* **All on by default** — when you first open a Project, every overlay is visible.
* **Toggle off** when an overlay is cluttering your view. You're not removing it from the Project, just hiding the layer locally.
* **Bulk hide** by tapping a "Hide all overlays" option if your app version exposes it. Useful when you want to see only your Records.

Toggle state persists across sessions for that Project — re-open the Project tomorrow and your visibility choices are remembered.

***

## Long-press to query overlay attributes

Overlays don't respond to single-tap (single-tap is reserved for Codifi Records). To see what's in an overlay:

1. **Long-press** the map at the spot you want to query.
2. The **disambiguation panel** opens with every layer at that point — overlays included.
3. Tap an overlay entry to see its attributes.

This is the equivalent of ArcGIS's "Identify" tool. For prior-coverage overlays (which often have rich attribute data), this is where you get details like Project name, date, recorder, results.

***

## "Use as Label" — making overlay attributes visible on the map

When you have an overlay attribute you reference often (e.g., parcel APN, prior Project number, recorder initials), you can promote that attribute to a visible **label** that draws on the map:

1. Long-press the overlay feature.
2. Open its attributes from the disambiguation panel.
3. Long-press the attribute value you want as a label.
4. Tap **Use as Label**.

Every feature in that overlay layer now renders with that attribute as its on-map label. Tap "Reset" or pick a different attribute to change.

***

## Layer ordering

Overlays render in this Z-order on the map:

```
┌──────────────────────────────────────┐
│ Codifi project records (your work)   │  top
├──────────────────────────────────────┤
│ Annotations and measurements         │
├──────────────────────────────────────┤
│ Map overlays (reference layers)      │
├──────────────────────────────────────┤
│ Basemap (satellite / streets / etc.) │  bottom
└──────────────────────────────────────┘
```

Your Records always sit visually on top of overlays, so you never lose track of your work behind reference data.

As of v3.3 raster imagery is pinned to the bottom of that stack with a fixed draw order, so it renders the same way every time regardless of how the map loaded or which layer you toggled last.

***

## Raster layers and coverage footprints

Raster layers such as scanned topo quads and hillshade are heavy. A single USGS 7.5-minute quad can be a hundred tiles or more, and a Project carrying several of them used to be able to overwhelm the device when the map opened at Project extent.

Two things changed in v3.3.

**Load guards.** Raster tiles no longer mount below a working zoom level, and the number of tiles held in memory at once is bounded. Open a Project at full extent and the imagery waits until you zoom into the ground you are actually working.

**Coverage footprints.** A raster layer can now be seen without being drawn. Each one can show a labeled outline of the ground it covers, so you can tell which sheet to switch on before you pay the cost of loading its imagery. This is the answer to the old problem of turning layers on one at a time to find the one covering your unit.

> **Screenshot placeholder:** *The Project map showing four labeled raster footprints as dashed outlines, with one raster switched on and rendering inside its footprint.*

{% hint style="info" %}
**Keep one or two rasters on at a time.** Even with the guards in place, several overlapping high-resolution rasters is a lot to ask of a tablet. If the map feels slow, switch the ones you are not using off.

Your Project Manager can also set which layers are on by default from the web app, so crews open the Project with a sensible starting set rather than everything at once.
{% endhint %}

***

## Photos as an overlay

In the layers sheet, you'll also find a **Photos** toggle. This isn't a PM-loaded overlay — it's a Codifi-managed layer showing every geotagged photo in the Project as camera markers.

See [Photos on the Map](/codifi-docs/mobile-app/capturing-photos-and-media/photos-on-the-map.md) for the full reference.

***

## Other things in the layers sheet

In addition to PM-loaded overlays and the Photos layer, the layers sheet typically includes:

| Layer                       | What it shows                                                                               |
| --------------------------- | ------------------------------------------------------------------------------------------- |
| **Basemap**                 | Style picker — satellite, streets, outdoors (terrain). Choose what backdrop suits the work. |
| **Basemap transparency**    | Fade the basemap so overlays and Records stand out.                                         |
| **Project Area / APE**      | The configured Project area or area of potential effect, if PM has set one.                 |
| **Offline area boundaries** | The footprint of the offline map tiles you've downloaded.                                   |
| **Labels**                  | Toggle on/off the labels Codifi shows on Records.                                           |
| **Photo markers**           | The Photos layer (see above).                                                               |

***

## When overlays don't render

A few causes:

* **The overlay isn't toggled on.** Check the layers sheet.
* **The Project hasn't synced the overlay yet.** Pull-to-refresh or open and close the app to trigger sync.
* **You're outside the basemap's offline area.** Overlays only render where you have basemap tiles cached.
* **The overlay's style doesn't render at this zoom level.** Some overlays are styled to disappear at very wide or very zoomed-in views. Try zooming.

***

## Common questions

### Why doesn't tapping an overlay select it?

Single-tap is reserved for Codifi Records. Use long-press to query overlays. This separation lets crews work fluidly with Records without accidentally selecting reference layers.

### Can I edit overlays from my iPad?

No — overlays are managed on the web by your PM. If an overlay has wrong data, report it to your PM for a web-side fix.

### How big can overlays be?

PMs can load very large overlays (hundreds of MB or more), though large ones take longer to sync and slow down map rendering on older iPads. If a Project's overlays feel sluggish, ask your PM whether some can be simplified or split.

### Can I add my own overlays in the field?

Not currently. Overlay management is a web-side workflow. In the field, **annotations** (sketches, labels, measurements) are the mobile-side answer for marking up the map for yourself.

***

## Related

* [**The Map Screen**](/codifi-docs/mobile-app/mapping-locations/understanding-the-map-screen.md) — broader map controls and gestures.
* [**Viewing & Filtering Records**](/codifi-docs/mobile-app/mapping-locations/viewing-and-filtering-records-on-the-map.md) — narrowing what shows on the map; overlays + filters compose.
* [**Annotation & Measurement Tools**](/codifi-docs/mobile-app/mapping-locations/annotation-and-measurement-tools.md) — the mobile-side answer for marking up the map yourself.
* [**Web: Map Setup & Offline Areas**](/codifi-docs/web-app/map-setup-and-offline-areas.md) — the configuration side, what your PM is doing when they load overlays.
* [**Photos on the Map**](/codifi-docs/mobile-app/capturing-photos-and-media/photos-on-the-map.md) — the Photos layer that lives in the same layers sheet.