Get map imagery ready for the field

Background imagery comes over the internet. The control module, DIG module and Ditch Assist Lite receiver Wi-Fi networks have no internet, so in the field the map can only show imagery already saved on the tablet. Anywhere you haven't saved it, the map is blank behind your position.

Save it at home, on internet Wi-Fi, for every field you plan to work.

Before you start

Time: about 5 minutes per field.

• The tablet is on Wi-Fi with internet: farm Wi-Fi or a phone hotspot, not the module network (Wi-Fi on the tablet).
• LiDAR & Mapping is unlocked on this tablet. The imagery choice lives on the same card (Unlock it once).

Cache a field's imagery

Preparing the field with LiDAR anyway? Use Prepare Field: Cache Satellite Imagery is one of its tick boxes, so you're done. For imagery alone:

1. Tap LiDAR & Mapping

   The bottom-right card on the Home screen. A window called LiDAR & Mapping opens with five choices.

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2. Tap Cache Satellite Imagery

   The second of the five choices, with a satellite icon. The map opens.

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3. Wait for the internet check, then tap OK

   The app checks it can reach the internet. If a window says Internet Required, switch to internet Wi-Fi and tap Retry. Then a short note called Cache Satellite Imagery appears: Locate each field you plan to work near, then tap around a rough boundary. The app will download satellite imagery and labels for offline use at that field. Tap OK.

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4. Find the field

   Drag the map with one finger and pinch to zoom (Pinch to zoom). The hint at the top left reads Tap to draw a rough boundary for imagery caching.

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5. Tap the corners of a rough box around the field

   Leave some room around the field for the headlands, the approach and the outlet. Up to 800 acres per box. The box at the top left counts the corners and acres. Undo and Clear, third and fourth down the right side, take back the last corner or start over.

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6. Tap Cache Imagery

   The second button in the column down the right side. A window called Cache Imagery opens: Draw a rough boundary around each field you expect to work near. The app will cache satellite imagery and labels for offline map use.

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7. Type a field name

   Tap the Field name box and type a name you'll recognise (Typing and the keyboard). With no name you get Enter a field name.

   If the keyboard covers the window, press the Back button once to hide it (The Back button).

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8. Tap Cache Imagery in the window

   The green button at its bottom right. A progress bar counts the tiles, for example Caching satellite imagery (412 tiles)... with 88 / 412 tiles under it, then the road and place labels. Keep the app on screen until it finishes. A small field takes a few seconds.

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9. Tap Close

   The window now reads Satellite Imagery Cached: Imagery for this field is cached and will be served automatically when the tablet is offline. Tap Close. Then draw the next field, or tap Done in the column down the right side to go Home.

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How the cache works

• What is saved: the Satellite imagery for the box, from wide views down to close-up field detail, plus road and place labels. Zooming in past that detail still works; the picture just gets softer.
• US Imagery is not pre-cached. In the field, use the Satellite background over fields you cached.
• Panning also caches. Any imagery the map shows while the tablet has internet is kept. Pan and zoom over a field at home and it will be there later, but only at the zoom levels you looked at. The Cache button is more thorough.
• It stays until you remove it. Cached imagery is kept between sessions. Deleting the LiDAR field does not remove its imagery.
• Where: Documents/DitchAssist/map-tile-cache/ when the app has All files access, so it survives a reinstall. Without that permission Android keeps it in the app's private storage and removes it with the app.

Clearing cached data

There is no button in v1.5.4 to clear cached satellite imagery. It doesn't need looking after.

The Offline Cache row, in the DRAIN-IQ section of the app's Settings, is for Drain-IQ layers only. Before the first download it reads No catalog loaded — tap Download All to fetch; afterwards something like 3 fields, 12/15 layers cached. It has up to two buttons:

• Download All (Update All once something is downloaded): downloads every Drain-IQ field for offline use. Needs internet.
• Clear, shown only once something is downloaded: deletes all downloaded Drain-IQ data after asking Delete All Drain-IQ Data? Layers download again the next time you use them online.

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Clear doesn't touch satellite imagery, your LiDAR & Mapping fields or your surveys and jobs.

If it doesn't work