Solution — Utility-scale solar
Topographic Survey for Solar Plant Layout and Pile Design
Levels, slopes and drainage paths across the whole site, so your layout engineer can place tables, piles and roads with confidence.
Quick AnswerA topographic survey for solar plant sites gives the layout team a ground model of the whole site: close-grid levels, contours, slope direction, drains, roads, trees and boundary. Large sites are flown by RTK drone on DGPS ground control, smaller ones walked with DGPS. Where the plant feeds a substation, read about getting a cable trench survey power plant done right.
What does a solar layout need from a topographic survey?
Three things above all: the slope in each direction, the natural drainage paths, and every fixed feature the module rows must avoid. The survey decides how many tables fit, how tall each pile stands, where internal roads go and whether inverter pads stay dry in August.
Satellite elevation data at the bid stage carries errors of several metres: fine for a capacity estimate, useless for pile design. The surveyed model replaces it once land is secured. For the method and drawings, see when you need a topographic survey.
Drone or ground crew: which suits your site?
Above about twenty-five acres a drone is nearly always faster and cheaper; below that, a DGPS crew on foot gives the same accuracy without the flight planning.
| Site condition | Best method | Why |
|---|---|---|
| Open, bare or cropped land, 25+ acres | RTK drone with DGPS ground control | Dense surface model in a few flying days |
| Small rooftop-adjacent or captive plant, under 25 acres | DGPS walk-over with level grid | No airspace or flight permission steps |
| Thick scrub or tree cover | Drone LiDAR | Pulses reach ground between branches |
| Fenced site with existing structures and cables | DGPS + total station, GPR where digging | Detail and buried services together |
| Long evacuation line to the grid substation | Route survey strip | Centreline with cross-sections every 25 m |
Table note: boundary checks against revenue records are a separate exercise covered by our land survey services; we often run both in one mobilisation.
Drone mapping needs airspace clearance under India's drone rules, and zones near airports or defence land are restricted. We check the zone map at the quoting stage.
What else goes on the drawing besides levels?
Everything fixed on or over the land that the module blocks, roads and fence must respect goes on the site plan. Our field list for a solar site includes:
- Boundary pillars, field bunds and the fence line, tied to your parcel map and land records.
- Village tracks and any right of way that neighbours use and you may have to keep open.
- Overhead lines with pole and tower positions, because their corridors cut usable area.
- Tube wells, irrigation channels, ponds, temples, graves and isolated trees.
- Nala and culvert inverts at the boundary, which fix where drainage can leave the land.
- The approach road, including bends and weak culverts that matter for transformer delivery.
How the field work runs on a large site
Control first, then flying or walking, then checks, so the model can be trusted and repeated. On day one the crew sets a DGPS base station on a stable point and builds a ring of control pillars around the land. Each pillar is observed long enough, with gps signals logged at base and rover, to tie it to the national frame. Ground targets and flying blocks follow. Independent check points, never used in processing, prove the height accuracy in the report.
Slope, trackers and pile heights
Surveyed levels set each pile's height, and the slope map shows where trackers can run and where fixed tilt is safer. Single-axis trackers rotate east to west on a north–south torque tube, and suppliers cap the slope along that axis at a few per cent. Fixed-tilt tables in India face south, so a north-facing slope pushes rows apart to avoid shading.
On a large site those differences add up to tonnes of steel. Spot levels on a grid suited to the terrain, with contour lines at 0.25 m or 0.5 m, let the structural designer choose pile lengths block by block.
Drainage and flood paths
Water decides more solar layouts than people expect. Flat land in the Indo-Gangetic plain hides depressions that hold water for weeks. Dry land in Rajasthan or the Deccan can carry violent sheet flow after a cloudburst, and loose sand in western Rajasthan shifts with the wind. The model shows catchment boundaries, low points and nala lines, so the civil designer can size drains, keep inverter pads on high ground and keep module rows off natural channels.
The survey also records how water leaves the land today: outlets cut through bunds, culverts under the approach road and the level of the nearest drain. If the only outlet is a small pipe under a village road, the drainage design must work with it or negotiate a bigger one.
Cable trenches, roads and the substation corner
Once the layout is fixed, the same control serves the construction layouts for roads, trenches and foundations. Near the grid end, other owners' cables are common. Before trenching near a substation or public road, scan the route and register the dig; our note on call before you dig in India explained covers the alert step. After commissioning, our page on what you receive from an as built survey describes the record of the buried DC and AC network.
Rates and a worked example
Solar sites are priced per acre; the larger the site, the lower the rate per acre. Current rates, exclusive of GST:
- Drone survey with orthomosaic and DEM/contours: from ₹40,000 per site up to 25 acres, then ₹1,500 per extra acre.
- Drone LiDAR with point cloud and terrain model: ₹2,500 per acre, minimum ₹1,50,000.
- Ground topographic survey: ₹4,000 per acre for the first 10 acres, then ₹2,500 for each acre beyond.
- Contour survey: ₹3,500 per acre for the first 10, then ₹2,000 for each acre beyond.
- DGPS ground control or boundary points: ₹3,000 per point.
- Evacuation route strip: ₹15,000 per km.
Example: a 200-acre site flown by drone costs ₹40,000 for the first 25 acres plus 175 × ₹1,500 = ₹2,62,500, so ₹3,02,500 before GST and ground control. If the same land were under dense scrub and needed LiDAR, the figure would be 200 × ₹2,500 = ₹5,00,000. Your written quote fixes the final amount.
A 200-acre site takes three to five field days. Crews reach NCR sites the same day or within 1 working day. In other states, a team member based in that region starts laying control at once or by the next working day. Any mobilisation or travel cost, if applicable, is shown in the written quote. Share the KMZ of your land parcels to plan a survey with us.
Frequently asked questions
How accurate is a drone survey for solar design?
With DGPS ground control, a few centimetres in height on open ground, which is ample for pile design and grading. Accuracy falls under crops or scrub, which is why LiDAR is used there.
What contour interval do solar designers ask for?
Most ask for 0.5 m, or 0.25 m on flat sites where drainage is the main concern.
Can you survey while the land is still being farmed?
Yes, standing crops limit ground visibility for a drone, so we either fly after harvest or switch to LiDAR or ground levels.
Do you need permission to fly a drone over our site?
Yes, India's drone rules require airspace clearance, and some zones are restricted. We check the zone at the quote stage.
Will we also get buried services on the drawing?
Only if a GPR scan is added in the areas you plan to trench. Its output is described in read GPR survey deliverables.
Can the same survey be used for the bank and lender's engineer?
Yes, we supply the control point list with its reference station details and a method note, so an independent reviewer can check the data.
Get a written quote for your solar site
Survey services for solar
Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026