ORTHOSMost property owners' mental picture of their own land comes from Google Earth or Maps — and that imagery is often one to three years old, doesn't reflect recent grading, construction, or boundary work, and was never accurate enough to measure anything from in the first place. An orthomosaic map fixes both problems at once: current, and actually measurable.
What "orthomosaic" means, in practice
A drone flies a grid pattern over the property, capturing hundreds of overlapping photos. Software stitches them into a single flat image and corrects for lens distortion, camera angle, and terrain relief — so unlike a regular photo, distances and areas on the finished map are geometrically accurate, not just visually plausible. Paired with RTK positioning, that accuracy holds to within a few centimeters.
Orthomosaic vs. satellite imagery vs. a licensed survey
| Source | Currency | Measurable? |
|---|---|---|
| Google Earth / Maps | Often 1-3 years old | Rough distances only, not reliable |
| Drone orthomosaic (RTK) | As current as the flight date | Yes — accurate to a few centimeters |
| Licensed land survey | As current as the survey date | Yes — legally binding boundary determination |
An orthomosaic isn't a substitute for a licensed boundary survey when a legal determination is actually required — but it's often the fast, low-cost reference layer that tells you whether you need one in the first place. A lot of grading, drainage, or encroachment questions get resolved with a current map alone.
What comes out of one flight
- Orthomosaic image — the single flat, geo-referenced photo of the whole property.
- Topographic / elevation data — contour lines from the same flight, useful for grading and drainage questions.
- GIS-ready exports — GeoTIFF and KMZ files that drop directly into whatever mapping software an engineer, agronomist, or county planner is already using.
Who actually needs this
Land buyers doing due diligence before closing, contractors tracking site progress against a plan, real estate listings that want more than a stock satellite thumbnail, and property owners settling a grading or drainage question before it becomes a dispute. If the property also carries a crop, a stockpile, or a roof worth checking, the same visit often covers a crop scan, a volume survey, or a thermal pass in one trip.
Frequently asked questions
How current is an orthomosaic map compared to satellite imagery?
As current as the day of the flight. Most public satellite imagery is one to three years old and doesn't reflect recent grading, construction, or boundary changes.
Can an orthomosaic map replace a licensed land survey?
No — it's a mapping and documentation product, not a legal boundary survey. It's a fast, accurate reference layer that often informs when a licensed survey is actually needed.
What file formats come with the deliverable?
Standard exports are a high-resolution image, a PDF summary, and GeoTIFF/KMZ files for GIS software. Other formats are available on request.
Orthos Aerial Group runs RTK-accurate aerial mapping across the Sacramento Valley — Redding to Sacramento.