LiDAR & Mapping

What this mode is for

Use LiDAR & Mapping while the tablet has internet, before you head into a controller-only WiFi workflow. Draw a rough field boundary once, enter the field name once, and choose what to prepare: cache satellite imagery, save a raw LiDAR DEM for contour generation, generate flow/depression mapping products, or run all selected products together.

The app fetches LiDAR elevation data from public sources (USGS 3DEP in the US, NRCan HRDEM in Canada). Flow lines, depressions and ponding are then computed on the tablet itself and saved locally — no data is sent anywhere for processing. Saved imagery, DEMs, and mapping layers remain available later when you are offline and connected back to the controller.

Internet is required to fetch or generate. Saved DEMs and layers reload offline.

The draw flow checks for real internet first. On entering any LiDAR & Mapping draw mode, the app probes for working internet with an HTTP check — being on Wi-Fi is not enough, because a controller hotspot has no internet upstream. While the probe runs, a Checking internet… banner shows over the map. If the check fails, a blocking Internet Required dialog appears with Retry and Back to Home buttons, and an Offline — connect to internet to draw banner stays on screen. Map taps do not add boundary points until internet is confirmed. Switch the tablet to a Wi-Fi network or hotspot with internet, then tap Retry.

One-time unlock. LiDAR & Mapping is gated behind a one-time real-controller-connection unlock — tap any of the Slope-IQ / Tiling / Excavator / etc. cards and successfully connect to a real controller (not simulator) once. After that the LiDAR & Mapping card unlocks and stays unlocked across app restarts. The unlock is per-install: if you reinstall the app, you will need to connect to a controller once again to re-unlock the feature. The unlock state is stored in the app's local settings, which uninstall removes. If you tap LiDAR & Mapping before unlocking, a locked dialog appears explaining the gate.

Workflow at a glance:

1. Connect to a real controller once if the card is still locked.
2. Switch the tablet back to internet WiFi.
3. Tap the LiDAR & Mapping card on Home and pick a mode on the popup (Prepare Field, Cache Satellite Imagery, Fetch LiDAR DEM, Generate Mapping Products, or Saved Fields / DEMs).
4. The map screen opens in that mode. Use the device-location button if needed to pan near your current area, then tap the map to draw a rough boundary. Use Undo or Clear if needed.
5. Tap the sidebar's primary button (e.g. Prepare Field). Enter a field name and choose any combination of:
   • Cache satellite imagery
   • Save LiDAR DEM for contours
   • Generate flow and depression mapping
6. Tap Run Selected and wait for the selected products to finish.
7. Repeat for each field you plan to work on soon.
8. Reconnect to the controller. Levee, Contour Tiling, and Contour-Guided Terracing can now use Saved LiDAR DEM offline.

Limits:

• Boundary up to 800 acres per fetch.
• The boundary may not self-intersect. Bowtie or hourglass-shaped polygons are rejected before submission with the message Polygon edges cross. Adjust your boundary. Vertices cannot be dragged — tap Undo to step back to the bad corner (or Clear to start over), then re-tap the corner where it doesn't cross.
• Resolution is auto-picked between 2 m/pixel (small fields) and 5 m/pixel (large fields), tuned to keep the upload small and the cloud job fast.

Coverage gaps:

• The US 3DEP service covers the entire continental US.
• The Canadian HRDEM service only covers parts of Canada. If your area is not covered, the app will tell you after the fetch completes (it checks the returned data).

Mode buttons

Each product can run separately or as one combined field-prep run. You pick the mode on the popup that opens when you tap the LiDAR & Mapping card on Home — before drawing. The map screen then opens in that mode, and the sidebar's primary button matches it (Prepare Field, Cache Imagery, Save DEM, or Generate Products):

• Prepare Field — one boundary and one field name, with checkboxes for imagery, saved DEM, and mapping products.
• Cache Satellite Imagery — caches imagery/labels for the drawn boundary only.
• Fetch LiDAR DEM — saves the raw elevation surface for offline contour generation (its confirm dialog is titled "Save LiDAR DEM" and the sidebar action is Save DEM).
• Generate Mapping Products — creates flow, ponding, and depression layers.
• Saved Fields / DEMs — opens the saved-field manager without adding boundary points.

Saved fields and DEMs

Open the Saved Fields / DEMs button in the sidebar (or the My LiDAR Fields entry from the Map Layers dialog) to see every field you have generated. Each field can be expanded to toggle individual layers (Boundary, Flow Routes, Ponding Risk, Depressions) on or off the map. Fields that include a source DEM are also available to Levee, Contour Tiling, Contour-Guided Terracing, and the map elevation checker. Delete a field to remove all its files.

Drainage Planner

Any field whose mapping products were generated on the tablet itself (not an older cloud-generated field) offers Open Drainage Planner — from the Prepare Field completion screen right after generating, or later from that field's row in Saved Fields / DEMs. Drag the minimum drainage area slider (0.1 to 20 acres) to thin the flow network down to the paths that drain at least that much ground; fewer, more meaningful lines remain as you raise it, and arrows point downstream. Tap Save plan to name and keep that threshold as a reusable plan for the field. Saved plans reload from Map Layers → Add Layer → Drainage plan.

Duplicate field names

If a field name's slug already exists, the new field is saved with a numeric suffix (-2, -3, ...) appended. Pick a unique name to avoid the auto-renaming.

Adjusting layers on the map:

Open Map Layers (the FAB on the map). Each ponding/depressions layer row has an expand caret — tap it to reveal the Opacity slider. Ponding layers also expose the Cutoff slider, which controls how shallow a pond has to be before it is hidden.

Storage location:

/storage/emulated/0/Documents/DitchAssist/lidar-fields/<slug>/ — one folder per field, plus a top-level fields.json catalog. A field-local --source-dem.tif is retained when you save a DEM or generate mapping products. Source WCS downloads are also cached under /storage/emulated/0/Documents/DitchAssist/lidar-dem-cache/ so the same LiDAR fetch can be reused later without switching back to internet WiFi. Satellite imagery cache metadata is tracked under the LiDAR field catalog, while the actual tiles live in the app's FMTC tile cache.

If processing fails:

The field is still saved with a warning marker, and the source DEM is kept on disk so support can investigate. Try again later or contact support.