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Geospatial Drone Solutions

Aerial Mapping & Orthomosaic Drone Mapping in St. Louis

Photogrammetry for Missouri and Southern Illinois: centimeter-resolution orthomosaics, surface models, and textured 3D meshes, georeferenced and ready for ArcGIS, AutoCAD, and Civil 3D.

What You Receive

A Measurable, Current Picture of Your Site

Photogrammetry reconstructs geometry from overlapping photographs. TerraSight flies a planned grid over the site, capturing hundreds to thousands of high-resolution images with precise GNSS positions, and processes them in professional photogrammetry software into a georeferenced orthomosaic, a digital surface model, a dense point cloud, and, where required, a textured 3D mesh.

The orthomosaic is the product most clients use daily. It is a single seamless image of the entire site, corrected for lens and terrain distortion so that distances, areas, and positions measured on it are true. At a ground sample distance of a few centimeters per pixel, it shows detail that satellite and county aerial imagery cannot: curb lines, stakes, pavement condition, erosion, and stockpile toes.

Because every image carries an accurate position, the same dataset supports volume calculations, cut/fill comparisons between flights, and as-built checks against design. For vegetated or wooded sites where a true ground surface matters, we recommend pairing photogrammetry with our drone LiDAR surveying service.

Standard Deliverables
Georeferenced Orthomosaic (GeoTIFF / JPG) Digital Surface Model (DSM) Digital Terrain Model (open ground) Dense Point Cloud (LAS / LAZ) Textured 3D Mesh (OBJ / FBX / PLY) Contours (DWG / SHP) Web Map Tiles / KMZ Volume & Cut/Fill Report (optional) Ground Control & Accuracy Report
Specifications
CameraIntegrated 20 MP RGB
ResolutionCentimeter-level ground sample distance
PositioningRTK / PPK GNSS + Ground Control
ProcessingPix4D / Metashape / DJI Terra
Coordinate SystemsMO / IL State Plane or project datum
Compatible WithArcGIS, QGIS, AutoCAD, Civil 3D
Who It Serves

Orthomosaic Mapping for Missouri & Illinois Projects

Anyone who needs to see, measure, and document a site without walking every foot of it. Photogrammetry fits a wide range of St. Louis-area work, from a single commercial lot to multi-square-mile land holdings.

General Contractors & Construction Managers

Recurring progress orthomosaics and 3D models for schedule verification, pay applications, and owner reporting on commercial and industrial sites.

Civil Engineers & Surveyors

Current base imagery, surface models, and planimetric detail for design, as-built comparison, and exhibit preparation.

Developers & Commercial Real Estate

High-resolution site imagery for due diligence, marketing, site plans, and entitlement submittals across St. Charles County and the metro.

Aggregate, Mining & Earthwork

Stockpile volumes, pit progression, and haul road condition from repeat flights, with change detection between datasets.

Municipalities & GIS Departments

Fresh orthoimagery for parks, infrastructure projects, and parcel updates when county-wide flights are out of date.

Agriculture & Land Managers

Field-scale orthomosaics and surface models for drainage planning, stand assessment, and documentation of Missouri and Illinois farmland.

How It Works

Capture. Process. Deliver.

Photogrammetry rewards careful planning. Overlap, altitude, lighting, and control all determine whether the output is a pretty picture or a measurable map.

01
Scoping & Flight Design

We confirm the area of interest, the ground sample distance you need, the coordinate system, and the deliverable list. The mission is planned with the overlap and altitude required to reconstruct the site reliably, including oblique passes for 3D models of structures.

02
Ground Control & Checkpoints

Ground control points are placed and surveyed with GNSS equipment where the project's accuracy requires them. Independent checkpoints are withheld from processing so that reported accuracy is a measurement, not an estimate.

03
Image Capture

An FAA Part 107 licensed, professionally trained pilot flies the mission with RTK/PPK positioning. Flights are timed for consistent lighting and minimal shadow, and image quality is reviewed on site before the crew leaves.

04
Photogrammetric Processing

Images are aligned, tied to control, and densified into a point cloud. The orthomosaic, surface model, and mesh are generated, then checked for seams, distortion, and residuals against checkpoints before any derivative products are produced.

05
Delivery & Integration

Deliverables are exported in your formats and coordinate system with an accuracy report. For recurring programs, each new dataset is aligned to the baseline so progress and volume comparisons are consistent flight to flight.

Why TerraSight

Mapping Built to Survey Discipline

Consumer drones can produce an orthomosaic. What they rarely produce is one you can measure from with confidence. TerraSight applies the same control, positioning, and quality review to photogrammetry that we apply to LiDAR: RTK/PPK positioning, surveyed ground control, withheld checkpoints, and a written accuracy statement with every delivery.

We also understand what the data is for. Orthomosaics are delivered in the projection your GIS or CAD already uses, point clouds are cleaned, and meshes are decimated to sizes that open without crashing a workstation. When a job calls for a different tool, such as LiDAR for a wooded tract or thermal imaging for a roof or array, we say so.

TerraSight operates from O'Fallon, Missouri and covers the St. Louis metro, St. Charles County, and Southern Illinois as local territory, which keeps repeat progress flights practical. Our processing stack is described on the technology page, and sample work is shown on the projects page. For contour and terrain deliverables from the same flight, see topographic mapping and contours.

  • Centimeter-level ground sample distance across the full site
  • RTK/PPK positioning with surveyed control and independent checkpoints
  • Professional photogrammetry software, not consumer apps
  • GeoTIFF, LAS/LAZ, OBJ/FBX, and DWG outputs in your coordinate system
  • Baseline-aligned repeat flights for progress and volume tracking
  • FAA Part 107 licensed pilots and full commercial insurance
  • Accuracy report included with every deliverable package
Side-by-side comparison of satellite imagery and a TerraSight drone orthomosaic showing resolution difference
Satellite (left) vs TerraSight Drone Orthomosaic (right) · Sample
Textured 3D mesh model generated from drone photogrammetry
Textured 3D Mesh From Photogrammetry · Sample Output
Questions

Drone Photogrammetry FAQ

What is an orthomosaic and how is it different from a satellite image?

An orthomosaic is a single, seamless aerial image assembled from hundreds or thousands of overlapping drone photos, each corrected for lens distortion and terrain relief so that scale is uniform and measurements are true. Drone orthomosaics are captured at a few centimeters per pixel, while typical commercial satellite imagery is 30 to 50 cm per pixel and often months old. The difference is visible immediately: individual pavement cracks, survey stakes, and stockpile edges are legible in a drone orthomosaic.

How accurate is drone photogrammetry?

With RTK/PPK positioning and ground control points, photogrammetric outputs can reach horizontal accuracy on the order of a few centimeters and vertical accuracy within several centimeters on open, well-textured ground. Accuracy degrades on vegetation, water, and uniform surfaces, which is why we use LiDAR for those conditions. Every project ships with an accuracy report that states the achieved values.

Can the 3D model and point cloud be used in CAD or GIS?

Yes. Orthomosaics are delivered as GeoTIFF for ArcGIS, QGIS, and Civil 3D; point clouds as LAS or LAZ; surface models as GeoTIFF rasters; and 3D meshes as OBJ, FBX, or PLY. All files are georeferenced in your project coordinate system, typically Missouri or Illinois State Plane.

When should I use photogrammetry instead of LiDAR?

Photogrammetry is the right choice when you need a high-resolution visual record, when the site is open and hard-surfaced, or when a textured 3D model matters, as with construction progress, stockpile inventory, and facility documentation. LiDAR is the right choice for wooded or brushy terrain, corridor mapping, and bare-earth modeling. Many projects benefit from both, captured on the same visit.

Where do you offer aerial mapping services?

TerraSight is based in O'Fallon, Missouri and provides photogrammetry and orthomosaic mapping throughout the St. Louis metro, St. Charles County, and Southern Illinois, including the Metro East. Projects elsewhere in Missouri and Illinois can be scheduled by arrangement.

Related Services

Extend the Dataset

Service
Drone LiDAR Surveying

Bare-earth terrain and classified point clouds where vegetation makes photogrammetry unreliable.
Service
Topographic Mapping & Contours

Contours, DEMs, and Civil 3D surfaces derived from the same aerial capture.
Service
Thermal & Infrared Inspections

Radiometric thermal orthomosaics for roofs, solar arrays, and electrical infrastructure.
Need Aerial Mapping in the St. Louis Area?
Send us the site boundary and the outputs you need. We will scope the flight, control, and deliverables.
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