Instructions & Guide
A community tool for underwater survey, sighting documentation, and marine biosecurity reporting — built for the protection of Aotearoa's coastal waters.
System Overview
The Dropcam Survey System has three parts:
- A 3D-printed dropcam housing — the STL file is available for download from the viewer's front page.
- An action camera — GoPro, DJI Action, SJCam, or similar. The camera must be able to display a live timestamp watermark on the recorded video — this is how we sync footage to GPS. Anything with the GoPro-style 2-prong mount in a waterproof case rated to 20 m will work.
- Two apps used as part of the workflow:
- Geo Tracker — used during the survey to record your GPS track.
- Dropcam Telemetry Viewer (dropcam.aat.nz) — used after the survey to synchronise footage, mark sightings, and submit reports.
The workflow is simple: record video underwater, record your movement with GPS, then synchronise and review both together later on a laptop or desktop.
Printing the Dropcam Housing
The dropcam housing is 3D-printed and designed to hold a standard action camera in its own waterproof case. Schools, libraries, and makerspaces are perfect places to get access to a printer if you don't have one.
What You'll Need
- A 3D printer with PLA or PETG filament
- The
.stlfile (download from the viewer header)
Print Settings
| Setting | Value |
|---|---|
| Material | PLA or PETG |
| Nozzle | 0.4 mm |
| Layer height | 0.3 mm |
| Infill | 35% |
| Orientation | Print standing upright |
| Parts | Main body and bottom screw printed separately |
The dropcam housing with an action camera fitted — sinkers sit inside the cylindrical section.
Preparing the Dropcam
The dropcam needs to sink steadily and stay vertical. Place old fishing sinkers inside the cylindrical section of the housing to achieve this. Tie your main line to the top attachment point and run a safety loop through the hole in the fin — this prevents accidental loss if something comes loose.
Before your first survey, test the fully assembled dropcam in a bucket or shallow water. Confirm it sinks smoothly, stays upright, and doesn't leak.
Camera Setup
The housing fits GoPro, DJI Action, and SJCam-sized action cameras — any camera with the GoPro-style 2-prong mount in a waterproof case rated to 20 m will work. The key requirement is that the camera must support a live timestamp watermark burnt into the video — this is how we sync footage to your GPS track. Most default camera presets are fine beyond that — resolution and frame rate aren't critical.
Before heading out, fully charge the camera, make sure you have enough storage for continuous video, and give the lens a good clean.
Using the Dropcam
A hand line works best, though a short stiff boat rod is also fine. Braid or nylon — either will do. Avoid long, flexible rods as they make control harder.
- Before dropping the camera in the water, do a slow pan around the area. That extra footage is useful later when reviewing and confirming location.
- Take a short video of your phone screen and make sure the time, especially the seconds, is clearly visible. This gives you a solid cross-check when syncing the video during review. Thanks Matt from MPI for that one.
- Try to stay at around 0.5 km/h. Once you move much faster, the footage becomes harder to review properly.
- DJI footage can be useful for aerial surveys, especially along coastlines.
- The system also works well for diver and snorkeller surveys where the diver records the video and the mobile phone or GPS recording stays in a float boat directly above them.
- Shoreline surveys above water can also be recorded in the same system for logging sightings.
How to Deploy
- Lower the dropcam slowly and steadily — avoid swinging.
- Touch the seabed gently so you know the depth, then lift the camera about 1 m off the bottom.
- Try to maintain roughly 1 m altitude as you drift or move to the next position — about 1–2 minutes of travel.
- Touch the bottom briefly every 1–2 minutes just to confirm you're still close, then lift back up.
- Avoid repeatedly bouncing off the seabed — each hit shakes the camera and the footage wobbles so much you can't see anything useful during review.
Lowering the dropcam over the side — slow and steady gets the best footage.
Care & Maintenance
A little care after each use will keep your dropcam in good shape for years.
Rinsing After Use
Always rinse the dropcam thoroughly with fresh water after every outing — saltwater accelerates corrosion and can cause the screw base to seize. Pay attention to the threads, line attachment point, and any hardware. Let it dry fully before storing.
Weights Housing
Empty the sinkers out after each use and give the inside a good rinse. Sand is the main thing to clear out — it can carry contamination (including Caulerpa fragments), and wet sand trapped inside will smell quickly. Shake out every last bit, rinse thoroughly, and store dry with the sinkers removed. Salt water and grit left sitting inside will also degrade the plastic over time.
Checking for Wear
Before each outing, give the housing a quick once-over:
- Check the screw base threads for wear or cracks — this is the most stressed part of the housing.
- Look for cracks or stress fractures around the line attachment point and fin.
- Check where the camera mount interfaces with the housing — repeated insertion and removal can cause fatigue over time.
- Inspect anywhere the housing has taken an impact.
Repairs
Small cracks and splits are easy to fix before they become big ones:
- Handheld 3D extruder pen — the best option for PLA/PETG repairs. Run matching filament into the crack and smooth it while warm. Strong, flexible, and waterproof.
- 5-minute Araldite (epoxy) — good for structural repairs, especially around attachment points and threads. Mix and apply to a clean, dry surface.
- Superglue (cyanoacrylate) — ideal for fine cracks and hairline splits. Wick it into the crack, hold firmly for 60 seconds. Not recommended for load-bearing joints on its own.
If the housing is badly cracked or the screw thread has failed, it's easier to just print a new one — the STL is free and a replacement prints in a few hours.
Recording GPS
You'll need a GPS tracking app on your phone that can export GPX files. We reccomend starting your GPS recording before you begin filming.
Android
Geo Tracker is our recommendation — it's free from the Play Store, clean, reliable, and easy to use. This is the only GPS app we've tested with so far.
iPhone
Gaia GPS is a good free option from the App Store. Other apps like GPX Master, Footpath Route Planner, or MotionX-GPS should also work as long as they can export a GPX file, though these haven't been tested.
Recommended Settings
- Recording interval: 1 second
- Distance filter: 0.5 m
- All other defaults are fine
When to Start and Stop
If you're launching from a kayak, paddleboard, or beach — start recording before you launch and keep the phone in a dry bag. From a larger boat, start recording just before your first drop. Leave GPS running throughout your survey — multiple dropcam locations are fine.
The rule is simple: as long as GPS is recording while you're recording video, you're good. Multiple dropcam locations are fine — you can define your transects later in the app during the review.
After your survey, export the GPX file via email, cloud, or USB. You'll need it on a laptop or desktop later.
Using the Dropcam Telemetry Viewer
This is where everything comes together. Open the viewer in your web browser at dropcam.aat.nz — Chrome, Firefox, Edge, or Safari all work fine. No installation needed.
1. Load Your Files
Click or drag your video file into the video drop zone, and your GPX track into the GPX drop zone. If you recorded with a DJI drone, you can load an SRT file instead of a GPX — see below.
The viewer layout — video on the left, map on the right, sightings panel below.
DJI Drone SRT Import
If you recorded aerial footage with a DJI drone (e.g. DJI Mini), you can use the .SRT subtitle file the drone generates alongside every video as your telemetry source — no GPX required. DJI SRT files contain embedded GPS coordinates, altitude, and absolute timestamps for every frame.
To use it: drag or click the GPX drop zone and select your .srt file.
The viewer converts it to a GPS track automatically and syncs the video to the beginning of the flight — no manual sync step needed.
The track appears on the map and playback works exactly as it does with a GPX file.
.srt file with the same name as the video in the same folder on the SD card.
Copy both the video and the SRT file to your computer before loading them.
2. Sync Video with GPS
The key to accurate positioning is matching the clock visible in your video with the GPX track time. Scrub the video to a frame where you can clearly read the timestamp on screen. Then adjust the video start time field so that the GPX position time lines up with the clock shown in the footage. Once they match, click Sync & Play — your position marker on the map will now move in sync with the video.
If the position looks off, click Resync, adjust the time, and sync again.
Match the clock in the video to the GPX time — then hit Sync & Play.
3. Add Transects (Optional)
You don't need to add transects — they're there if you want to define and measure specific survey lines as part of your work. Right-click the map or cursor and choose Start Transect, or use the panel button — the button turns green and the End button pulses. Move to the end point, right-click again, and choose End Transect (or click Set End in the panel). The map will show a red start triangle and a blue finish square for each transect, connected by a green line.
3a. Use Overlays for Planning & Repeat Surveys
The Overlays tab lets you load additional GPX tracks on top of your current survey. This is useful for transect planning, especially when you want to compare your intended run lines with previous work in the same area.
Overlays are also useful for repeat surveys. You can load historical survey GPX files and visually line them up with the current track so you can run the same area again with better consistency.
We also use overlays to compare changes at the same location over time, and to combine underwater and DJI aerial surveys in the same review session.
A dedicated GPX editor is planned for a future release, but for now overlays provide a practical way to reference older survey lines and plan new ones before and during field review.
3b. Map Layers
The map includes several toggle-able overlay layers accessible from the layer control in the bottom-right corner. These help you understand the regulatory and environmental context of your survey area at a glance.
Restricted Zones
A unified overlay showing marine protection and restriction areas colour-coded by type:
- Blue — High Protection Areas (HPA)
- Green — Seafloor Protection Areas (SPA) and Benthic Protection Areas (BPA)
- Red — Marine Reserves
- Orange — Cable and Pipeline Protection Zones
Click any zone to see its name, legal reference, rules summary, and a link to official information. Hover over a zone to see its name as a tooltip.
CAN Boundaries
Controlled Area Notice zones for Caulerpa. Red zones are high-risk areas with strict restrictions. Yellow zones are controlled areas with modified rules. Sourced from MPI's public ArcGIS data and cross-referenced with the latest MPI caulerpa rules.
Rāhui / Closures
Temporary closures (s186A), rāhui tapu areas, and mātaitai reserves. These include the current Ōmaha Bay, Kawau Bay, and Whangaparāoa Peninsula temporary closures, Bay of Islands rāhui, and the Aotea/Great Barrier rāhui tapū. Click any area for details including species restrictions, gazette references, and expiry dates.
Priority Zones
Risk-based surveillance priority zones derived from the national Caulerpa prioritisation framework. Each zone is scored across four weighted dimensions — introduction risk, environmental suitability, proximity to known infestations, and economic/social consequence — with override rules for culturally significant and protected areas.
- Red dashed — High priority (score 34–45). Highest vessel traffic, confirmed infestations, or protected area overrides.
- Amber dashed — Medium priority (score 22–33). Good habitat and moderate risk factors, or elevated by iwi/protected status.
- Grey dashed — Low priority (score <22). Comparative reference zones with lower suitability.
Click any zone to see its full score breakdown, override rationale, key risk factors, and known infestations. Zones use dashed borders and low-opacity fills so underlying regulatory and sighting layers remain visible.
Other Layers
- Coastal Names — place names for coastal features, bays, and headlands.
- WMP Sightings — confirmed Caulerpa sightings from the Weed Management Programme.
- iNaturalist Caulerpa — Caulerpa observations from iNaturalist NZ, colour-coded red for exotic species and purple for native. Click for species, photo, date, and a link to iNaturalist. Updated weekly.
- Community Sightings — Caulerpa observations reported through the community sighting viewer.
- LINZ Aerial (NZ) — high-resolution aerial imagery from Land Information New Zealand.
- Nautical Chart — OpenSeaMap navigation marks and depth data.
4. Log Sightings
When you spot something, press S on the keyboard or click Add Sighting (or use the floating button in fullscreen mode). A frame is captured automatically. Fill in the details — name, notes, biota type, density, and benthic description.
Sightings appear in the list and as markers on the map. If you've defined transects, sightings will automatically assign to the correct one based on their timestamp. Timeline ticks let you jump back to any sighting instantly, and you can click the edit button or open the image lightbox to update details at any time.
The sighting modal — captured frame, biota type, density, benthic, and notes.
5. Waypoints, Boundaries & Ruler
The map has a right-click context menu that changes depending on what you click — the map, a waypoint, or the track cursor. These tools let you annotate your survey with spatial detail that carries through to the final report.
Waypoints
Right-click the map and choose Add Waypoint to drop a labelled marker. You can drag waypoints to reposition them, and right-click a waypoint to delete it. Waypoints are included in the exported GPX and report with NZTM coordinates.
Boundary Areas
Boundaries let you outline areas of interest — like a caulerpa patch or a reef edge. Right-click and choose Boundary Leg to start drawing. The cursor becomes a crosshair and a dotted yellow preview line follows the mouse. Left-click to place each vertex. Vertices will snap to nearby waypoints or existing boundary points automatically. Right-click to finish, or press Escape to cancel. To close a polygon, click near the first vertex and it will snap shut. The area is calculated and shown below the map.
Boundary areas outlined on the map with named labels and area measurements.
Click on a boundary line to delete the nearest vertex. Right-click and choose Clear Boundary to remove all boundaries. If a boundary leg is attached to a waypoint, the boundary moves with the waypoint when you drag it.
Ruler
Right-click the map and choose Start Ruler to place the first point, then right-click again and choose Add Ruler Point to place the second. A dashed yellow line appears with the distance and heading shown below the map. Drag the markers to adjust. Click the ruler line to clear and start over.
Track Trimming
If your GPX has unwanted data before or after the survey, right-click the cursor marker (the green dot on the track) and choose Trim Track Before Cursor or Trim Track After Cursor. Trimming is blocked if any sightings or transects would be lost — you'll need to remove them first.
Map-Only Live Position
In map-only mode, you can enable Show Live Position to place a blue GPS marker on the map using your phone or tablet's current browser location. This is useful when returning to a previously logged sighting, waypoint, or point on the survey track.
Once the blue Live Position marker is showing, right-click a sighting, waypoint, or the green track cursor and choose Navigate To Here. The viewer draws a dotted blue line from your live position to the selected target. Use Clear Navigation to remove the current route.
6. Fill in Survey Info
The Survey Info tab captures your agency, survey name, method, site code, date, operator details, and water temperatures. This metadata travels with your export so agencies know exactly what they're looking at.
7. Export & Submit
The Reporting tab is where you package and send your survey. You have several options:
- Save GPX — downloads an updated GPX with all your waypoints, transects, boundaries, ruler, and metadata.
- Archive Survey — creates a local ZIP backup of your survey data.
- Export — sends your GPX, metadata, and sighting images to the processing agent, which generates a ZIP containing a cover PDF with satellite map and summary, an Excel workbook with full data sheets (including waypoints, boundary areas, and ruler measurements), annotated images, and full metadata. The ZIP can be downloaded to your browser or emailed directly.
The Reporting tab — choose your export targets and hit Export.
Keyboard Shortcuts
| Key | Action |
|---|---|
| S | Add sighting — captures the current video frame and opens the sighting modal. |
| Escape | Cancel boundary drawing if in progress, or close the image lightbox. |
Right-Click Menu
The context menu is the main way to interact with the map. It adapts based on exactly what you right-click — the open map, a waypoint marker, a boundary label, a boundary line, or the track cursor. Only the actions that make sense in that context are shown, so the menu stays clean and uncluttered.
The context menu adapts to show only relevant actions for what you clicked.
On the Map (open area)
- Start Transect — begins a new transect at the clicked location. The Start button in the panel turns green.
- End Transect — finishes the active transect at the clicked location (visible only when a transect is in progress).
- Add Waypoint — drops a labelled waypoint marker you can drag to reposition. Included in GPX export with NZTM coordinates.
- Boundary Leg — starts drawing a new boundary polygon from the clicked point. The cursor becomes a crosshair and a preview line follows your mouse. Left-click to place each vertex; right-click or press Escape to finish. Click near the first vertex to close and form a polygon.
- Delete Boundary Leg — removes the nearest boundary leg (line segment) to where you clicked.
- Delete All Boundaries — clears all boundary polygons from the map.
- Start Ruler — places the first ruler point. Right-click again and choose Add Ruler Point to complete the measurement. Distance and bearing are shown below the map. Drag either marker to adjust.
- Add Ruler Point — adds the next ruler point (visible after Start Ruler has been used). Multiple points create a multi-segment ruler with a total distance.
- Delete Ruler — removes the ruler line and markers.
On a Waypoint
- Rename Waypoint — opens a prompt to give the waypoint a custom name. The label updates immediately on the map and in the export.
- Delete Waypoint — removes the waypoint. Any boundary vertices attached to it are also removed.
- Boundary Leg — starts a new boundary polygon snapped to the waypoint's exact location.
- Start Ruler — begins a ruler measurement from the waypoint's location.
- Navigate To Here — in map-only mode with Show Live Position enabled, draws a dotted blue line from your live GPS position to this waypoint.
On a Sighting
- Navigate To Here — in map-only mode with Show Live Position enabled, draws a dotted blue line from your live GPS position to this sighting.
On a Boundary Area Label
- Rename Area — opens a prompt to give the boundary a custom name (e.g. "Caulerpa Patch A", "Survey Zone 1"). Names appear on the map label and in the export report.
- Delete Area — removes that individual boundary polygon.
On the Track Cursor
Right-click the green cursor marker that follows the GPS track as video plays.
- Start Transect — starts a new transect at the cursor's current position on the track.
- End Transect — ends the active transect at the cursor's position.
- Navigate To Here — in map-only mode with Show Live Position enabled, draws a dotted blue line from your live GPS position to the cursor's current track position.
- Trim Track Before Cursor — removes all track points before the cursor. Useful for cleaning up GPS data recorded before you arrived at the site. Blocked if sightings or transects would be lost.
- Trim Track After Cursor — removes all track points after the cursor. Useful if GPS kept recording after the survey ended. Blocked if sightings or transects would be lost.
While Live Navigation Is Active
- Clear Navigation — removes the current dotted blue route from the live position marker to the selected target.
AI Object Detection
In the Reporting tab, enable the Object Detection toggle before submitting. Your sighting images will be run through the AI model during processing — detections are drawn on the images and summarised in the Excel report and cover PDF.
AI detection in action — bounding boxes drawn around identified objects.
Data & Privacy
Your video and GPX files never leave your computer until you choose to export. See the landing page for our full privacy statement.
Tips for Good Surveys
Before You Go
- Charge everything — phone, camera, spare batteries.
- Make sure your GPS app is recording before you start video.
- Sync your camera clock as close to your phone time as possible.
- Clear enough storage for continuous video.
- Clean the lens well.
During the Survey
- Keep GPS running the entire time — don't stop until you're done.
- Go slow — around 0.5 km/h is ideal for review. Pause occasionally to get a clear frame. Try to keep the camera directly below you — if it's out the back, it's now a towcam and you're travelling too fast.
- Take a slow video pan of your surroundings at the start and finish of each drop, and make mental notes of landmarks — they help with syncing later.
- If practical, film your phone screen for a few seconds before the drop so you can verify the time stamp, including the seconds count, during review.
- DJI footage can be useful for aerial surveys, especially on coastlines.
- The system also works well for diver and snorkeller surveys where the diver records the video and the mobile phone or GPS recording stays in a float boat directly above them.
- Shoreline surveys above water can also be recorded in the same system for logging sightings.
Example dropcam footage — clear view of the seabed with good visibility.
Documenting Sightings
Good notes make a real difference. Be specific about what you see:
- Size and extent of the patch
- Density — scattered, moderate, or dense
- What the seabed looks like — sand, rock, mud, mixed
- Nearby features — moorings, structures, channel edges
Troubleshooting
| Problem | What to Check |
|---|---|
| Map doesn't move with video | Make sure you've clicked Sync & Play and that the video start time is correct. |
| GPS position is way off | Click Resync, adjust the start time, and sync again. |
| Video won't play | Check the format — MP4, WebM, and MOV are supported. Try converting with VLC if needed. |
| GPX file won't load | Confirm it's a .gpx file, not KML or another format. |
| SRT file won't load or shows no track | Confirm the SRT is from a DJI drone and contains embedded telemetry (latitude, longitude, abs_alt lines inside each subtitle block). SRT files from non-DJI cameras or subtitle-only files won't work. |
| Export button disabled | You need a GPX loaded, at least one sighting, Survey Name and Site Code filled in, and images loaded for sightings. |
| Agent shows offline | Check the status dot in the viewer header. The agent may be temporarily unavailable. |
Sharing Your Survey
Your exported data helps the people and organisations working to protect our marine environments:
- Our kids and future generations — so they inherit healthy coastlines and thriving ecosystems.
- Our native marine animals, critters, plants, and natural environment — every sighting contributes to their protection.
- Ministry for Primary Industries (MPI) — national biosecurity tracking and eradication coordination.
- Regional Councils — local monitoring, management planning, and resource allocation.
- Iwi and hapū — protecting mahinga kai, traditional fishing grounds, and sites of cultural significance.
- Community groups — citizen science programmes, local monitoring, and awareness.
What's Ahead
This project is a living thing — it grows as the community's needs grow. Here's what we're working towards: