How to Plan Your First Grid Survey Mission in Dronelytics
A grid survey is the foundation of drone mapping. Whether you are shooting a roof inspection, documenting construction progress, or mapping agricultural fields, the process starts the same way: draw an area, set your parameters, and generate a flight path.
This drone grid survey tutorial walks through each step - from choosing the right grid type to dialing in your overlap and altitude settings. By the end, you will know how to plan a repeatable drone mapping mission in under two minutes.
What Is a Grid Survey Mission?
A grid survey flies your drone in a lawnmower pattern across a defined area, capturing overlapping photos at regular intervals. Processing software (like Pix4D, DroneDeploy, or WebODM) stitches those photos into orthomosaics, 3D models, or elevation maps.
The quality of your final deliverable depends almost entirely on how you set up the grid. Get the overlap, altitude, and speed right, and the software does the rest. Get them wrong, and you are re-flying the job.
Step 1: Choose Your Grid Type
Dronelytics offers three grid types. Pick the one that matches your site.
Rectangle Grid
Best for simple, roughly rectangular areas. Parking lots, flat roofs, open fields. Draw a rectangle and the planner generates parallel flight lines automatically.
Polygon Grid
Best for irregular boundaries. L-shaped buildings, property lines that follow roads, oddly shaped parcels. Drop vertices to trace the boundary, and the grid fills the shape.
Circle Grid
Best for radial coverage around a central point. Stockpile measurements, tower surroundings, circular structures. Set the center and radius, and the grid covers the area.
Most jobs use rectangle or polygon grids. Circle grids are situational but save significant time when the site calls for them.
Step 2: Check the Airspace
Before you plan any mission, verify that you can fly at the site. Check the airspace class, look for TFRs and restrictions, and confirm your LAANC authorization ceiling if you are in controlled airspace.
Read the full airspace guide or go directly to the airspace map to check your site.
This takes 30 seconds and prevents the 2-hour round trip to a site you cannot legally fly.
Step 3: Draw Your Survey Area
Open the mission planner and select your grid type. Then draw your survey boundary on the map:
- Rectangle: Click two opposite corners. The planner fills in the rectangle.
- Polygon: Click to place vertices around your boundary. Close the polygon by clicking the first point.
- Circle: Click the center point, then drag to set the radius.
Position your boundary with some buffer beyond the actual area of interest. Photogrammetry software produces better results at the edges when photos extend slightly past the boundary.
Step 4: Set Your Grid Parameters
This is where drone mapping mission planning gets specific. Four settings determine the quality and efficiency of your survey.
Front Overlap (%)
The overlap between consecutive photos along each flight line. Higher overlap gives the photogrammetry software more data to match features, but increases flight time and photo count. Minimum for usable results: 65%. Standard for most commercial work: 75-80%. High-accuracy work (volumetrics, 3D models): 80-85%.
Side Overlap (%)
The overlap between adjacent flight lines. Same trade-off as front overlap. Minimum: 60%. Standard: 65-70%. High-accuracy: 70-80%.
Altitude (AGL)
Flight height above ground level. Lower altitude means higher ground resolution (smaller GSD), but more flight lines and longer flight time. Roof inspections: 100-150 ft. Construction: 150-200 ft. Agriculture: 200-300 ft. Large area surveys: 300-400 ft.
Camera Angle
Nadir (straight down) for orthomosaics and 2D maps. Oblique (angled) for 3D models and building facades. Some jobs benefit from a crosshatch pattern - one pass nadir, one pass oblique.
Speed
Faster saves battery and flight time. Slower reduces motion blur. For most commercial drones at 150-250 ft altitude, 15-25 mph produces sharp images. Reduce speed in low light.
Step 5: Enable Terrain Follow
If your survey area has any elevation change - hills, slopes, berms, or uneven terrain - enable terrain follow.
Without terrain follow, your drone flies at a fixed altitude above the takeoff point (MSL). Over a hill, that means you are closer to the ground. In a valley, you are farther away. Your ground sampling distance varies across the survey, and steep slopes create collision risk.
Terrain follow adjusts altitude continuously to maintain a constant height above ground level (AGL). Your photos have consistent resolution across the entire survey area, and you avoid terrain collisions.
Most competing drone survey planning tools charge $18/month extra for terrain follow. Dronelytics includes it free. Here's why.
Step 6: Review and Save Your Mission
Before you fly, review the generated mission:
- Waypoint count - Confirm the flight path covers your entire survey area
- Estimated flight time - Compare against your battery capacity. A DJI Mavic 3 gets roughly 40 minutes. Plan for a 25-30 minute effective mission with reserves.
- Photo count - Higher overlap and lower altitude mean more photos. Make sure your SD card has space.
- Flight direction - Adjust the grid angle if needed. Aligning flight lines with the longest dimension of your site reduces turns and saves battery.
Save the mission to your library. Reuse it for recurring jobs - construction progress monitoring, seasonal agricultural surveys, or monthly site documentation. After your flight, log the results - read our guide to choosing a flight logging platform.
Companion Apps for the Field
Plan in Dronelytics, monitor in the field with our free companion apps. MAVLink Telemetry gives you live GPS, altitude, battery, and attitude data from ArduPilot and PX4 drones on your iPhone. SkyPinger tracks nearby manned aircraft with ADS-B so you know what is flying in your area.
MAVLink Telemetry
SkyPinger
Grid Settings Cheat Sheet
Quick reference for common drone survey grid settings by job type:
Roof Inspection
Front: 80% | Side: 70% | Alt: 100-150 ft | Angle: Nadir | Speed: 15 mph
Construction Progress
Front: 80% | Side: 75% | Alt: 150-200 ft | Angle: Nadir + Oblique | Speed: 18 mph
Agricultural Survey
Front: 75% | Side: 65% | Alt: 200-300 ft | Angle: Nadir | Speed: 22 mph
Stockpile Volume
Front: 85% | Side: 80% | Alt: 100-150 ft | Angle: Nadir | Speed: 12 mph
Real Estate Aerial
Front: 75% | Side: 65% | Alt: 150-200 ft | Angle: Nadir + Oblique | Speed: 18 mph
These are starting points. Adjust based on your camera sensor, lighting conditions, and processing software requirements. For a deep dive on each setting, see our complete guide to drone survey grid settings.
Looking for the right tool to plan these missions? See our comparison of the best free drone mission planning software.
Start Your First Grid Survey
Dronelytics makes drone mapping mission planning straightforward. Draw your area, set your parameters, enable terrain follow, and fly.
Free — no credit card required.
Sign Up