Difference Between Aerial and Terrestrial Photogrammetry Explained

Photogrammetry is a fascinating field that lets us map and measure the world around us. Aerial and terrestrial photogrammetry are the two main techniques used to capture this data. But what is the real difference between aerial and terrestrial photogrammetry? And why should you care? If you’ve ever wondered which method suits your needs best, you’ve come to the right place. Let’s explore these techniques and see how they compare.

Aerial photogrammetry involves capturing images from airborne platforms, while terrestrial photogrammetry uses ground-based equipment. Aerial methods cover large areas and are ideal for topographic mapping, whereas terrestrial methods provide higher detail for smaller-scale projects.

What is Aerial Photogrammetry?

Aerial photogrammetry involves taking photos from above the ground, typically using a camera mounted on an aircraft or drone. These images are stitched together to create a large-scale map or 3D model of the landscape below. UAV-based photogrammetry has become increasingly popular for aerial surveys as drones can capture precise data in less time.

The goal of aerial photogrammetry is to cover large areas quickly. It is often used in topographic mapping, urban planning, and environmental studies. The sensor platform is airborne, meaning it offers a broader field of view, covering everything from mountain ranges to fields.

What is Terrestrial Photogrammetry?

Terrestrial photogrammetry, also known as ground-based surveying, involves taking pictures at ground level. Cameras are often mounted on tripods or handheld devices to capture the scene from the ground perspective. This approach is typically used for 3D terrain modeling of smaller areas where detail is essential.

Terrestrial photogrammetry is ideal for architectural surveys, infrastructure inspections, and archaeological studies. The image perspective is captured from eye level, which results in high-resolution, detailed imagery of specific objects or locations.

Comparison Criteria: How Are Aerial and Terrestrial Photogrammetry Different?

To make it easier for you to decide which method to choose, we’ll compare aerial and terrestrial photogrammetry based on several key factors. This comparison will help you understand the benefits, limitations, and ideal use cases of each technique.

Side-by-Side Comparison: Aerial vs. Terrestrial Photogrammetry

Let’s break it down by the following factors:

Criteria	Aerial Photogrammetry	Terrestrial Photogrammetry
Camera Type	Airborne camera systems	Ground-mounted or handheld cameras
Sensor Platform	Aircraft, drones (UAV)	Tripods, handheld devices
Image Perspective	Top-down view	Ground-level perspective
Elevation Data	Suitable for large-scale elevation	Detailed elevation for smaller areas
Coverage Area	Wide, broad area coverage	Limited coverage, detailed focus
Resolution	Moderate, depends on altitude	High resolution due to close proximity
Field of View	Extensive, landscape-level	Focused, object-level
Accuracy	Good for general mapping	High precision for specific objects
Cost	Generally higher due to equipment	Typically lower in comparison
Accessibility	Requires specialized equipment	Easier to conduct with basic tools
Processing Complexity	More complex due to volume	Less complex, smaller data sets
Surveying Speed	Fast, covers large areas quickly	Slower, more detail-oriented
Environmental Impact	Low impact with UAVs, potentially high with aircraft	Minimal, low environmental footprint
Data Collection Method	Remote sensing, aerial photography	Manual ground-level photography
Weather Dependency	Highly weather-dependent	Less affected by weather conditions

Understanding the Camera Types and Sensor Platforms

One major difference between aerial and terrestrial photogrammetry is the camera type and sensor platform. Aerial photogrammetry often involves sophisticated airborne camera systems, which are attached to drones or planes. These cameras are built to capture wide areas in less time. In contrast, terrestrial photogrammetry uses cameras mounted on tripods or handheld devices, allowing for up-close, detailed photography of specific objects.

Coverage Area and Field of View

If coverage area is your main concern, aerial photogrammetry wins hands down. It allows for a broad field of view, making it ideal for capturing topographic mapping or extensive landscape projects. Terrestrial photogrammetry, however, provides a focused view with incredible detail—perfect for projects like architectural surveys or infrastructure analysis.

Accuracy and Resolution Comparison

Aerial photogrammetry provides a good level of accuracy for general mapping purposes, especially when accuracy isn’t the primary concern. However, if you need pinpoint accuracy and high resolution, terrestrial photogrammetry is your go-to. Because the camera is closer to the object, it can capture detailed features that aerial methods might miss.

Cost, Accessibility, and Weather Dependency

Cost and accessibility are significant factors. Aerial photogrammetry tends to be more expensive due to the need for aircraft, drones, and specialized equipment. It’s also heavily affected by weather conditions. Cloudy skies or high winds can easily disrupt aerial data collection.

In contrast, terrestrial photogrammetry is generally more affordable. It’s also less affected by weather, making it a more reliable option in regions with unpredictable climates. Ground-based surveying can be done with basic equipment, making it more accessible to a wider range of users.

Analysis and Insights: Which One Should You Choose?

Aerial photogrammetry is perfect if you’re looking to map large areas and need to get it done quickly. It’s highly efficient and can give you a great top-down view of the landscape. However, it can be costly and depends heavily on good weather.

Terrestrial photogrammetry, on the other hand, is great for capturing detailed, high-resolution images of specific structures or objects. It’s easier to access and usually more affordable compared to aerial techniques. But, it lacks the speed and wide coverage of aerial methods, making it better suited for smaller-scale projects.

Pros and Cons: Aerial Photogrammetry

• Pros:
  • Quick coverage of large areas
  • Ideal for topographic mapping
  • Capable of gathering data from hard-to-reach places
• Cons:
  • Weather dependency can cause delays
  • Higher cost due to specialized equipment

Pros and Cons: Terrestrial Photogrammetry

• Pros:
  • High accuracy and resolution
  • Great for capturing details of specific structures
  • More accessible and affordable
• Cons:
  • Limited coverage area
  • Takes more time to survey large areas

Conclusion

The difference between aerial and terrestrial photogrammetry boils down to coverage, resolution, and cost. Aerial photogrammetry is the best choice for capturing wide areas quickly, while terrestrial photogrammetry offers better resolution and detail at a lower cost. Your choice ultimately depends on your project requirements—whether you need speed and coverage or detail and precision.

If you want to understand more about photogrammetry techniques, or explore other methods like LiDAR vs. photogrammetry, check out this detailed comparison. To learn more about the different types of photogrammetry, you can also read this informative guide.

FAQs: Aerial Photogrammetry Vs. Terrestrial Photogrammetry