High-Accuracy Aerial Survey Under Flight Restrictions

Bugzeye provides recurring aerial mapping for a large commercial development in the greater Phoenix area, supporting an engineering workflow with current orthophotos, terrain data, CAD point information, and point clouds.

The project includes a 50-acre section of an active development site that requires repeat surveys as construction progresses, ownership changes, and new improvements are added. Despite a maximum flight altitude of 200 feet, the workflow is designed to produce consistent, usable data across repeated survey cycles.

The Challenge

The project site is located near active military operations, which limits drone flights to a maximum altitude of 200 feet.

That restriction creates additional challenges for aerial mapping, particularly around buildings, site edges, vegetation, and other vertical features. Because the site changes regularly, the workflow also needs to produce comparable results from one survey cycle to the next. 

Fieldwork & Data Collection

Bugzeye uses DJI Matrice 300 and Matrice 350 aircraft equipped with the DJI P1 camera for high-resolution aerial data collection. For projects requiring NDAA-compliant equipment, Bugzeye can also deploy the senseFly eBee X fixed-wing platform, which is particularly well suited for efficient large-area mapping.

The 50-acre portion of this project typically requires about two hours of flight time. Ground control points are placed using survey targets to support positional accuracy. 

Five-Flight Photogrammetry Workflow

To improve data completeness at the restricted altitude, the team uses a five-flight collection strategy:

1. 1. One nadir flight for orthoimagery
   2. One 45-degree oblique flight from the north
   3. One 45-degree oblique flight from the east
   4. One 45-degree oblique flight from the south
   5. One 45-degree oblique flight from the west

The combination of nadir and oblique imagery improves coverage around building facades, site edges, vegetation, and other features that can be difficult to capture completely from a single perspective. 

Processing Workflow

Aerial imagery is processed using 3Dsurvey for photogrammetry, point-cloud processing, terrain modeling, and CAD-related workflows.

Processing for a typical survey cycle can require approximately 36–50 hours of computer processing, depending on the dataset. Bugzeye also uses this workflow on much larger mapping projects, including projects exceeding 3,700 acres. 

Project Deliverables

Typical deliverables for the project include:

• • Orthophoto
  • CAD point grid
  • Digital Terrain Model (DTM)
  • LAS / LAZ point cloud compatible with Carlson

These datasets support downstream engineering and CAD workflows and provide a repeatable record of changing site conditions. 3Dsurvey

Results

The repeatable collection and processing workflow has helped Bugzeye maintain consistent results across multiple survey cycles while working within the site's flight restrictions.

The workflow produces:

• • detailed orthoimagery
  • improved terrain models
  • defined building edges
  • point clouds for engineering and CAD use
  • comparable datasets across repeat visits 3Dsurvey

Featured by 3Dsurvey

This Bugzeye project was also featured by 3Dsurvey as a technical customer case study examining the flight-planning and processing workflow used on the site.

Read the full 3Dsurvey case study