Short answer: look past the drone. The firm should have legally registered drones and certified pilots, prove its accuracy with independent checkpoints, show sample deliverables and references from similar projects, and process the data in-house. Everything else follows from those.
The checklist
- Registered drones and certified pilots. Under the Drone Rules, 2021, drones are registered on the Digital Sky platform and pilots hold a DGCA remote pilot certificate from an authorised drone school.
- An accuracy report with checkpoints. Ask for RMSE in X, Y and Z measured on checkpoints that were not used in processing. Without it, the accuracy is unproven.
- The right GSD for the job. The quote should state the ground sample distance. Check it with our GSD calculator.
- DGPS ground control by surveyors. Who measures the GCPs, with what equipment, in which coordinate system and height datum?
- Sample deliverables. Ask for a sample orthomosaic, terrain model and drawing from a past project, in the formats your team uses.
- References from similar projects. A highway DPR, a railway ESP and a solar thermography job need different skills. Ask for named clients.
- Processing and drafting in-house. Firms that only fly hand the hard part to someone else. Ask who builds the models and drawings.
- Airspace planning. They should check the Digital Sky zone map for your site and plan any permission before quoting dates.
- Clear scope and data ownership. The contract should list every deliverable and say that the raw and processed data belong to you.
- Method honesty. A good firm will tell you when LiDAR or a ground survey is the better tool. See LiDAR vs photogrammetry.
Questions to ask in the first call
- What GSD and how many GCPs and checkpoints will you use?
- Will you give an accuracy report with RMSE?
- Which similar projects have you done, and for whom?
- Who processes the data and prepares the drawings?
- What exactly will I receive, in which formats, and when?
How DATA PKT answers these
We are empanelled with NHAI in three zones, have flown highway surveys since October 2020, and our GIS and drafting teams work in-house in Gurugram. Our clients include NHAI, NHIDCL, Indian Railways, DMRC and more than 80 contractors. See our case studies and company facts.