Heritage Grain Silos Digitally Preserved Through Integrated UAV and 3D Laser Scanning Survey

Project Overview

With decades of experience delivering surveying, mapping, and reality-capture solutions across industrial, infrastructure, cultural heritage, and urban renewal projects, Tianbaonet continues to help clients transform complex physical assets into accurate digital models.

In a recent heritage preservation project in the Pearl River Delta region of Guangdong, China, Tianbaonet successfully completed the high-precision surveying and facade mapping of a historic grain silo complex using an integrated aerial-and-ground data acquisition workflow.

The project involved eight cylindrical grain silos and several rectangular storage buildings constructed between the 1950s and 1970s. As important witnesses to the region's industrial and agricultural development, these structures are now being considered for preservation, renovation, and adaptive reuse. Accurate geometric documentation was therefore essential for future maintenance, restoration planning, and digital archiving.

The Challenge: Surveying Complex Historic Structures

The client required precise calculations of:

• Cylindrical wall surface areas

• Conical roof surface areas

• Circumferences and dimensions

• Detailed facade drawings for each silo

However, several challenges made conventional surveying methods inefficient:

Complex Curved Geometry

The cylindrical shape of the silos made traditional total station point-by-point measurements difficult and time-consuming. Capturing sufficient points for accurate curve fitting would significantly increase fieldwork duration.

Restricted Site Conditions

The industrial facility featured narrow access roads, uneven terrain, dense vegetation, and limited lines of sight, creating obstacles for conventional surveying equipment.

Inaccessible Roof Structures

The elevated conical roofs and ventilation openings were difficult to reach safely from ground level, making complete data collection challenging.

To overcome these limitations, Tianbaonet designed a comprehensive reality-capture solution combining UAV photogrammetry and handheld LiDAR scanning.

The Solution: Integrated Aerial and Ground Surveying

Tianbaonet implemented an aerial-ground integrated surveying workflow based on the China Geodetic Coordinate System 2000 (CGCS2000), ensuring accurate alignment between all datasets.

Aerial Survey for Complete Roof Coverage

For roof and upper-structure documentation, the team deployed a DJI Mavic 3 Enterprise equipped with:

• 4/3 CMOS wide-angle camera

• Mechanical shutter

• RTK positioning module

The UAV mission was carefully planned to ensure complete coverage of the silo roofs and upper facades.

Key flight parameters included:

• Flight altitude exceeding surrounding structures

• 85% forward and side overlap

• RTK-enabled georeferencing within the national coordinate framework

This approach enabled the capture of areas inaccessible to personnel and conventional equipment while maintaining high geometric accuracy.

Ground-Based LiDAR Scanning for Detailed Facades

To capture the vertical structures and architectural details, Tianbaonet utilized the Lingguang L2 Pro handheld 3D laser scanner.

The scanner provided:

• 360° * 270° field of view

• Mobile SLAM-based data collection

• Real-time RTK integration

• Colorized point cloud generation

Operators freely walked around the silos, stairways, ventilation openings, and interior spaces, rapidly collecting high-density point cloud data.

The system's mobility made it particularly effective in the confined industrial environment where tripod-based equipment would have been difficult to deploy.

Workflow and Data Processing

Field Data Acquisition

The field survey included:

1. UAV flight planning and aerial image capture

2. Exterior facade scanning

3. Interior silo scanning

4. Unified coordinate control using CGCS2000

By combining aerial and terrestrial datasets, Tianbaonet ensured complete coverage of all visible structural elements.

Matrice 3E aerial photography of the top of the grain silo

Use L2pro to scan the granary

Data Processing and Model Generation

Following data acquisition, the workflow included:

• Aerial triangulation and photogrammetric reconstruction

• LiDAR point cloud preprocessing

• Noise reduction and registration

• Aerial-ground data fusion

• Complete colorized point cloud generation

The resulting model provided a highly accurate digital representation of the entire grain silo complex, including previously inaccessible roof structures.

After aerial triangulation, a 3D reconstruction is generated and exported as a LAS model.

Grain Silo Colorized Point Cloud Model

Grain Silo Interior Point Cloud

Grain Silo Layout Map

Rooftop point cloud data of the grain silos successfully acquired using integrated UAV and ground scanning.

Engineering Deliverables

The fused point cloud data was imported into CAD software for detailed engineering analysis.

Using cross-sectional extraction and geometric fitting techniques, Tianbaonet generated:

• Precise circumference measurements

• Surface area calculations

• Dimensional annotations

• 1:1 scale facade elevation drawings

These deliverables provide reliable reference data for future renovation, maintenance, and structural assessment activities.

Project Results

The integrated surveying approach delivered several key outcomes:

Complete Digital Documentation

The project successfully captured all visible structural elements, including roof sections that would have been difficult or unsafe to measure using traditional methods.

Accurate Surface Calculations

Detailed measurements of cylindrical walls and conical roof surfaces were generated for all eight grain silos.

High-Quality Engineering Drawings

Comprehensive facade drawings, dimensional layouts, and circumference annotations were produced to support engineering applications.

Long-Term Digital Assets

The client received a complete set of digital resources, including:

• Colorized point clouds

• 3D models

• CAD drawings

• Measurement datasets

These assets can support future monitoring, restoration planning, renovation design, and digital heritage preservation initiatives.

Integrated Aerial-Ground Colorized Point Cloud Model of the Grain Silo Complex

Circumference Calculation in CAD

Unwrapped Facade Drawing of the Eight Cylindrical Grain Silos

Calculating Surface Areas of Cylinders, Truncated Cones, and Cones with Full-Scale Silo Dimensions

Why Integrated Reality Capture Matters

This project demonstrates the effectiveness of combining UAV photogrammetry with mobile LiDAR scanning for challenging industrial and heritage documentation projects.

Compared with conventional surveying methods, the integrated workflow provided:

• Faster field data collection

• Reduced site access limitations

• Comprehensive coverage without blind spots

• Centimeter-level accuracy

• Improved efficiency for curved and irregular structures

Most importantly, it enabled the creation of a complete digital record of historically significant buildings while minimizing disruption to the site.

About Tianbaonet

Tianbaonet has extensive experience delivering surveying, mapping, 3D laser scanning, UAV photogrammetry, SLAM-based reality capture, and digital twin solutions across a wide range of industries.

From industrial facilities and infrastructure assets to cultural heritage sites and urban renewal projects, Tianbaonet helps organizations capture, manage, and utilize spatial data with greater efficiency and accuracy.

As demand for digital asset management and heritage preservation continues to grow, Tianbaonet remains committed to providing innovative geospatial technologies that bridge the gap between the physical world and its digital future.