Prepare a field with LiDAR & Mapping

LiDAR Drainage Mapping is the feature's name; on the tablet its Home card reads LiDAR & Mapping. Prepare Field is the one-stop way to get a field ready. You draw the field once, type its name once, and the app fetches public LiDAR for it. It saves three things on the tablet: offline imagery, the raw LiDAR elevation surface (the DEM, a digital elevation model) and the drainage layers.

All of it needs internet. Do it at the shop or the house, on farm Wi-Fi or a phone hotspot, before you join the control module Wi-Fi.

Before you start

Time: about 10 minutes per field, most of it finding the field on the map. The run itself takes seconds.

• LiDAR & Mapping is unlocked on this tablet (see Unlock it once)
• The tablet is on Wi-Fi or a hotspot with internet, not the control module, DIG module or Reach network (Wi-Fi on the tablet)
• You know roughly where the field is. The map has satellite imagery with road and place labels to help you find it.
• The field is in the US (USGS 3DEP covers the lower 48) or in a part of Canada that NRCan HRDEM covers

Unlock it once

LiDAR & Mapping is for Ditch Assist® owners. Until this install of the app has seen a real kit, tapping the card opens a window called LiDAR & Mapping is for Ditch Assist owners. It lists the one-time steps:

1. On your tablet, open WiFi settings and connect to your Ditch Assist Control Module's WiFi network. The password is 12345678.
2. Come back to this app, tap any workflow card, and choose Connect to link the tablet to the controller. That activates LiDAR Mapping.
3. Switch the tablet back to your normal internet (cellular or home WiFi) and open LiDAR Mapping any time.

Any one of these unlocks it for good:

• Connect once to a control module (Full Automation or Guidance Only Kit), the normal way: Connect to your kit.
• Connect once to a DIG™ module.
• Activate a Ditch Assist Lite receiver (Activate your receiver).

The simulator and a Bluetooth GPS don't unlock it. The unlock stays through app restarts and updates, but not through an uninstall: after a reinstall, connect once more.

Prepare the field

Tap LiDAR & Mapping

On the Home screen, tap the LiDAR & Mapping card. It's the bottom-right card in the grid of nine, with a mountain-peaks picture. A window called LiDAR & Mapping opens with five choices.

If a survey or job is open, a window called Start New Session? comes first. Tap Start New: it clears what's on screen, but saved files stay on the tablet.

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Tap Prepare Field

It's the first of the five choices, with a list-and-tick icon. The map opens.

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The map opens. Before you can draw, three things happen. None of them changes the buttons on the map:

1. Wait while it checks the internet

   A banner reads Checking internet… for a moment. Being on Wi-Fi isn't enough: the app checks it can really reach the internet.

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2. Allow location, if Android asks

   The first time, Android asks: Allow Ditch Assist to access this device's location? Tap While using the app, the top button of the Android window. The map then centres on where the tablet is. More on these Android windows: Tablet basics.

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   If you tap Don't allow, nothing breaks: the map starts where it was last, and you move it to the field yourself.

3. Tap OK on the Prepare Field note

   A short white window called Prepare Field explains the job: Locate the field, draw one rough boundary, then enter the field name once and choose whether to cache imagery, save a LiDAR DEM, generate mapping products, or run all selected products together. Tap the green OK at its bottom right. The window closes and the map is ready.

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Find the field

Drag the map with one finger to move it. Pinch two fingers apart to zoom in (Pinch to zoom). Stop when the field fills most of the map. Road and place names help you find it.

You should see the hint in the top-left corner: Tap to draw a field boundary for combined prep.

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Tap each corner of the field

Tap the map once at each corner, going round the field in order. Each tap drops a white dot. The box at the top left counts them, for example 4 vertices · 251 ac. From the third corner the outline is drawn closed and filled orange.

• A rough outline is fine. Take in the ground that drains toward your ditch, not only the fence line.
• Corners can't be dragged. Tap Undo (third button down the right side) to take back the last corner. Tap Clear (fourth) to start over.
• The edges must not cross each other (no bow-tie shapes).
• Up to 800 acres. Past that the count turns red and adds (over 800 ac limit).

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Tap Prepare Field

Look at the column of buttons down the right-hand side of the screen. The second button from the top says Prepare Field. Tap it.

First check the size readout in the top-left corner of the map. It shows how many corners you placed and the field's size, for example 4 vertices · 251 ac.

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A window called Prepare Field opens. That's the next step.

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Type a field name

In the Prepare Field window, tap the Field name box near the top. The keyboard opens (Typing and the keyboard). Type a name you'll recognise in a list, for example the farm and field number.

If the keyboard covers the window, press the Back button once to hide it (The Back button). A second press closes the window; your outline stays on the map, and you tap Prepare Field again.

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Leave the three boxes ticked

All three products are ticked to start with. Leave them ticked unless you have a reason not to.

Tick box	What you get
Cache Satellite Imagery	Imagery and labels for the field saved on the tablet, so the map isn't blank on the module Wi-Fi. See Offline imagery.
Save LiDAR DEM for contours	The raw LiDAR elevation surface. Levee, Contour Tiling, Contour-Guided Terracing and the elevation check use it offline. Greyed and marked Included with mapping products while the next box is ticked; untick the mapping and you can choose it on its own.
Generate flow and depression mapping	Flow lines, depressions and ponding, worked out on the tablet. See Read the drainage layers.

With nothing ticked you get Select at least one field-prep product.

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Leave LiDAR source on Auto

LiDAR source is the row of three choices under the tick boxes. Auto is selected (filled) to start with.

• Auto picks US or Canada from where the field is. Right almost every time.
• US (3DEP): USGS 3DEP, which covers the lower 48 states.
• Canada (HRDEM): NRCan HRDEM. It covers only parts of Canada; the app finds out after the download whether your field has data.

Pick one by hand only for a field right on the border. With only imagery ticked, the row disappears: no LiDAR is fetched.

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Tap Run Selected

The green button at the bottom right of the window. The run starts.

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Wait for it to finish

A progress bar runs through the stages. Keep the app open on screen and the tablet on the same Wi-Fi until it finishes. A quarter or half section usually takes a few seconds; a big field with imagery takes longer.

• Fetching elevation (2.8 m/px)… downloads the LiDAR. The detail is picked for you: 2 m per pixel on a quarter section, coarser (up to 5 m) on the biggest fields.
• Checking LiDAR coverage… makes sure the download really has elevation in it.
• Analyzing drainage…, then Tracing flow paths…, Finding depressions…, Ranking where water ponds first… and Saving layers…. This all runs on the tablet; nothing is sent away for processing.
• Caching satellite imagery (N tiles)... and Caching map labels..., with a tile count.

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Tap Close, or Open Drainage Planner

The window now reads Field Prep Complete: Selected field products are saved and available offline.

The flow lines and ponding are already on the map. Depressions are added to Map Layers switched off, one tap away.

• Open Drainage Planner (green, right): thin the flow lines down to the ones worth a ditch and save them as a plan. See Drainage Planner.
• Close (left): back to the map. Draw the next field, or tap Done in the column down the right side to go Home.

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Then go to the field

1. Join the module Wi-Fi and connect

   As usual (Connect to your kit). Everything you prepared stays on the tablet.

2. Show the layers on your survey or grade map

   Add them from Map Layers, with My LiDAR Fields or Drainage plan in its + menu. Step by step: Open My LiDAR Fields. Overlays are not kept after the app closes, so add them again each session.

3. Use the DEM

   Levee, Contour Tiling and Contour-Guided Terracing offer Saved LiDAR DEM as a contour source, and the height button on the map checks LiDAR elevation. See Saved fields and DEMs and Check LiDAR elevation.

No internet where you are?

Nothing in LiDAR & Mapping can fetch or generate without internet. Your choices:

• Phone hotspot. Turn on your phone's hotspot and join it from the tablet (Wi-Fi on the tablet). Prepare the field. Then go back to the module Wi-Fi.
• Prepare ahead. Do every field you expect to work this season at home. Saved fields work offline for as long as you keep them.
• Office route. Plan on a computer in the Geo-Surface™ owner portal and copy the map ZIP to the tablet.
• No LiDAR coverage at all? Drive a field survey instead; Levee and the contour workflows build their surface from it.

If you start a LiDAR download from Levee or a contour workflow while the tablet is on the module Wi-Fi, the app shows Internet Required for LiDAR. Tap Disconnect Controller. Switch the tablet to internet Wi-Fi. Then come back and fetch.

One product at a time

The other choices on the LiDAR & Mapping list do one job each. You draw a boundary the same way; the sidebar button names the job.

If you reached Save DEM from Levee or a contour workflow and a control module or activated receiver is connected, LiDAR DEM Saved offers Generate Contours Now. Otherwise it reads DEM saved. Reconnect to the controller, then choose Saved LiDAR DEM in Levee, Tiling, or Terracing.

Good to know

• Same name twice: both fields show with the same name in the list (only the second one's folder gets -2 on the end), so they are hard to tell apart. Use a new name or delete the old field first.
• LiDAR is a snapshot. It shows the ground on the day it was flown, which can be years ago. Ditches dug or filled since, tile and culverts don't show.
• Grading still uses your RTK survey. The LiDAR helps you pick the route; the design comes from what you survey on the ground.
• Where it's kept: Documents/DitchAssist/lidar-fields/, one folder per field. See Files on the tablet.

If it doesn't work

More: LiDAR & Mapping is locked, offline or fails.