Satellites can photograph a whole city in one pass. Drones can map a construction site in an afternoon. Neither one can walk up to a boundary pillar and confirm, to the centimetre, exactly where a legal property line sits. For that, someone still has to physically be there, and that's where ground survey earns its keep.

From Chains to Satellites

Traditional field survey once meant chains, plane tables, and theodolites, all manually recorded, all painstakingly slow. Modern equipment replaced that entirely. Total Station, often paired directly with GPS, now captures the same measurements digitally, ready for direct GIS import without a single manual transcription step.

Combined, these two instruments give a survey crew both precision and mobility, Total Station for the fine detail, GPS for quickly tying that detail back into a known coordinate system across a wider area.

Why "GPS Accuracy" Is a Trick Question

Here's what surprises most people: there's no single number for GPS accuracy. It swings wildly depending on the equipment and correction method used. Tap along the scale below to see just how much that range actually spans.

That range, from 30 metres down to a few centimetres, is the entire reason "GPS accurate" means almost nothing without qualification. A DGPS & RTK survey uses a fixed reference station to correct satellite signal errors in real time, which is exactly how survey teams reach that centimetre-level precision civilian GPS alone can't touch.

How Many Satellites Does It Actually Take

A GPS receiver needs signal from a minimum of three satellites to calculate a 2D position, and four to add elevation. Tap the button below to see the difference a fourth satellite makes.

Satellites give you where. Ground survey gives you certainty.

On projects where a few centimetres decide a legal dispute, a construction alignment, or a land acquisition boundary, that certainty isn't optional. This is why serious infrastructure and construction projects still budget for ground survey, even when satellite and drone data already cover the broader site.

Next time your phone shows "accurate to 5 metres," remember that's civilian GPS doing its best. For anything that needs to hold up in a legal document or a construction drawing, that number needs to shrink by two orders of magnitude, and that only happens with real ground survey behind it.