What is an orthomosaic?

If you’re asking this question, we’ll assume that you have just begun to explore the exciting world of aerial photography, and mapping with drones… and you should know that you are not alone in wondering how drones make maps.

An Ortho-rectified photo mosaic, or orthomosaic, is broken down into two parts. Ortho — meaning straightened or aligned and Mosaic — piecing things together.

Drones are a great tool for photography. But when we want to make an image of something really big, one picture can’t capture everything. With small drones we can take many photos looking straight down from above, hundreds if not thousands of photos, and by stitching these images together into a single scene they become a new, larger photo map, or ‘orthomosaic’ (aka orthomap).

multiple individual drone images when pieced together make an orthomap or an orthomosaic map

Properly pre-processing each photo individually is key. Every photograph must be ortho and geo-rectified (corrected for lens distortion, camera tilt perspective, etc) before stitching them together.

Here’s a simple comparison of the difference between layering photos before and after proper pre-processing corrections.

two drone captured photos overlapping with no photogrammetry do not align

Aerial photos layered without pre-processing

Properly processed with photogrammetry overlapping images are aligned seamlessly making an orthomosaic

After pre-processing 

The difference is more than aesthetic, these corrections allow for accurate location and distance measurements within the photo map. i.e. How long are the containers? How far away are they from a loading dock? After processing the aerial photos into an orthomosaic we can answer those questions and so many more!

With these larger, geospatially referenced photomaps, we create maps and models:

  • Property maps
  • Monitoring progress of construction projects
  • Earthworks
  • Volumetrics
  • Bare earth modeling
  • Crop damage analysis
  • Area calculations

How can we do so many things with drones? Our team of remote sensing and GIS experts use several sets of software combined with our own customized processing. This allows us to create the best deliverables for our clients.

Specifically for the Skymatics Crop Damage Analysis, we utilize the DroneDeploy platform (they have a free 30-day trial here). Users upload drone imagery of their fields and request Skymatics Crop Damage Reports(we’ll throw in the first one for FREE). Through RGB imagery we provide precise damage analysis for crop loss claims verification, easily displaying the extent of damage to the field. Insurers and growers are both benefiting from this transparent third-party analysis.

This is just the tip of the iceberg when it comes to imaging, are you interested in learning more? We’ll get further in-depth into photogrammetry in upcoming blogs. You can also click here to sign up for our monthly emails.