Drones and satellites are both methods for capturing imagery that can be used to create 3D maps using photogrammetry. While the Summit Evolution photogrammetric workstation can create projects from essentially any stereo image source, not all methods for taking photos produce the same results. 

For industries, such as forestry, DOTs, and agriculture that rely on photogrammetry to survey, plan, and, monitor a variety of functions, it’s important to understand what method to use based on the situation. In this blog, we’ll discuss the advantages of drones or satellites for five specific features and how they apply to the process of photogrammetry. 

1. Precision and Quality of Imagery 

Drones are flown at a much closer distance to the Earth than satellites. While there are regulations in place that determine how high drones are allowed to fly, current records show that the highest altitude a drone can physically reach is 10km, or 33,000 feet. For reference, this is about 4,000 feet higher than Mount Everest, the world’s tallest mountain. 

However, legal limitations require drones fly at a much lower latitude. The FAA set a max altitude of 400 feet above the ground for drone pilots, with some exceptions. 

Satellites, on the other hand, are positioned high in the earth’s atmosphere. Low Earth Orbiting satellites, which have the lowest altitude and are the most often used for satellite imaging, sit between 160 to 2000 km (over 100 miles). 

Since drones take images from such a close distance, they take high-resolution images that aid in creating highly precise, detailed maps. When you need to conduct a precise analysis, such as performing a tree count, drones are a strong choice. 

Satellite imagery is also obscured under certain weather conditions, such as high clouds, whereas drones may be able to take high-quality imagery in these situations. Additionally, GPS or GNSS drones also utilize a GPS position signal to provide accurate location and position data that is used to create highly precise 3D maps.

2. Scalability and Area Coverage 

While being so close to the Earth gives drones an advantage in creating high-resolution, precise stereo images, satellites are sometimes the better choice when a large area of land needs to be mapped. Since satellites are higher above the Earth, they can more readily capture large swaths of landcover. 

Drones capture imagery by flying over a designated spot using a controller. Each device has its own controller range, which varies depending on the quality of the drone. Most consumer drones may begin to lose signal after a mile, whereas high-end, long-range drones can sometimes travel as far as six miles from a controller. 

Battery life is also a consideration when mapping large areas. The size and quality of a drone has a large impact on how long the battery can last. 30 minutes is a good average for typical consumer drones, while most professional models can fly for at least one hour. In general, fixed wing drones, which are the most efficient drone type, can cover up to 900 miles in an hour.  

3. Autonomy & Ease of Use

There are several factors that go into the convenience of choosing drones or satellites. If you need to gather data immediately, drones can usually be deployed at any time. Satellites travel in a prescribed orbit. While polar-orbiting satellites cover a spot multiple times a day, others may only pass a certain area every couple of days — meaning you can gather new data sporadically. 

Satellites are autonomous; you often only need to request the resulting imagery. Drones, on the other hand, need to be piloted, which requires work, licensing, and skill to do. 

Additionally, there are many regulations surrounding drones that make some projects difficult. Areas that hard to access may also be difficult to fly a drone through. While drones are usually a much better option than surveying difficult terrain on foot, it can still be a challenge to fly drones through locations with heavy foliage, hills, or mountains. 

4. Imagery Affordability 

Purchasing commercial satellite imagery is often cheaper than hiring someone to collect professional drone imagery. The cost of satellite imagery has become much more affordable in recent years due to enhanced technology and changes in how organizations conduct business in space. 

While there are several factors that affect cost, hiring a drone photographer is often priced between $100 to $350 an hour. With larger areas, such as extensive farms, this can be a considerable sum to pay to acquire enough photos to create a 3D map. However, for people who own and operate their own drones, these costs are much lower. 

5. Mapping Consistency 

As mentioned previously, drones have a very limited battery life. It’s common for photographers to charge the device multiple times to cover an entire area, and batteries can take at least an hour to charge. This means there is plenty of time for minute environmental change to occur, including sun angle. 

Satellites, on the other hand, can take a in a wide-swath image in one moment. You generally don’t need to worry about potential changes in elevation or the position of the sun. Stitching together multiple low-altitude drone images can take time.

However, satellite images can sometimes be too consistent for the project at hand. When you want to capture the land at different angles, you won’t see that with satellite imagery. Drones, on the other hand, can be maneuvered to take images from a variety of orientations. 

Make the Best of Both Worlds With Summit Evolution

The question of satellites vs. drones is one that has existed since the early 2000s when drones first became popular for commercial use. And the answer to this query has only grown more complicated as both satellite and drone technology continue to advance. Since their inception, drones can efficiently travel much farther for longer. The image quality and affordability of satellites has increased greatly in recent years as well.  

Many industries have chosen to adopt both types of technology — leaning on the strengths of both drones and satellites. When a project calls for precise, high-quality imagery or only covers a small space, a drone can quickly be deployed for the job at hand. When mapping extensive areas of land that need to be consistently monitored over time, satellites offer an advantage. 

No matter which type of imagery you utilize, the Summit Evolution photogrammetric workstation can transform both types of stereo imagery into meaningful 3D data that allow you to map, interpret, analyze, and plan for a variety of projects. 

This innovative software comes with a wide variety of image manipulation tools, such as real-time panning and zooming, histogram equalization, and on-the-fly image adjustments. It improves vector data accuracy by removing pixel limitations, and offers interior, exterior, relative, and absolute orientation tools. 

It features a robust, user-friendly project management window and a variety of other tools and menus for the best user experience. And we offer several licensing levels which allow you to purchase only the tools you need for your photogrammetric programs. 

At DAT/EM Systems International, we want to make sure our customers are happy with our product and that it best meets their 3D mapping needs. We offer a free 30-day demo period so you can test out Summit Evolution for yourself. We welcome you to give it a try!

Ready to take advantage of your free demo? Contact us for more information.