It is interesting to look back and see that we have come a long way in terms of earth observatory technology and satellite imagery. In the 1840s, scientists strapped cameras to kites and balloons to observe landscapes from the sky. Even after launching satellites into space, the images they captured were low-resolution used mainly for military purposes. Nowadays, it is quite different. Thousands of satellites orbiting the earth provide some of the highest resolution satellite imagery in near real-time. What makes it even better is that much of these satellite images can be accessed from public sources for free or from commercial sources at cheap rates.
Earth observation data has become indispensable for lots of companies. That is why this article will provide a comprehensive guide to using satellites and searching for satellite imagery.
How can satellite imagery help your business?
Rapid changes in the satellite marketplace have brought about new opportunities for many different companies. Earth observation data is primarily used across industries, such as civil engineering, transportation, real estate, humanitarian aid, finance & insurance, energy, agriculture, land administration, and more.
The importance of satellite imagery to your business will largely depend on the industry you are operating. The agribusiness will benefit from crops, livestock, soil, weather, and route monitoring. In real estate, satellite images can be used to determine land value. We could keep on listing more benefits across different industries. However, the main idea is that data and images from satellites can be processed and analyzed using sophisticated technologies like machine learning to solve complex business problems.
Types of satellite imagery
The image-capturing method of a satellite determines the type of image it generates. These satellites use remote sensing techniques to monitor the characteristics of the earth and the changes that it undergoes. Remote sensing is the ability to determine the properties of an object without physically coming in contact with it. There are two main types of satellites based on how they capture imagery: active and passive.
Passive satellites use electromagnetic radiation produced by the sun as an energy source that illuminates the object for monitoring. So, once the radiation from the sun hits the earth’s surface, it is reflected or absorbed and then re-emitted based on the object it touches. The sensors on the satellite pick up the reflected light and can identify objects based on their reflection and absorption properties. The downside to this type of imaging is that it is highly dependent on the day-night cycle. Passive sensors are not effective at night because there is no radiation from the sun.
On the other hand, active sensors can generate their own source of energy which serves for illumination. The sensors send a beam of radiation to the earth’s surface and pick up the reflected signals, which are then processed and analyzed. These sensors can operate at any time since they do not need energy from the sun.
What is spatial resolution?
Spatial resolution refers to the smallest object that a satellite sensor can detect on the earth’s surface. This does not translate into whether the object will be recognizable or not. It simply means the smallest size, which a single pixel in the sensor covers on the ground. For example, Landsat data has a 30m resolution. It means that each pixel covers a 30m x 30m area on the earth’s surface. This image is considered medium-resolution and can cover an entire city. However, fine details like houses and cars will not be distinguishable.
The classification of the low, medium and high-resolution images is not absolute because technology is advancing rapidly. For example, in the 80s, Landsat had a 60m per pixel resolution and was considered high-resolution. Nowadays, that is classified as low resolution. The highest resolution satellite imagery provided by commercial satellites today is 30cm.
Where to start the search?
If you are a newbie in the earth observation imagery world, an excellent place to start is comparing Sentinel, Landsat, and MODIS imagery with high-resolution images from Maxar. Landsat is a joint program between the United States Geological Survey and NASA that has been around for about 40 years.
You will need to decide which factors are most important for your intended use of earth observation data. Normally, you should choose a source that has the data for your area of interest. Also, you need to decide on your budget and the spatial resolution you need.
Final Thoughts:
As we have seen above, satellite imagery is becoming beneficial for businesses across many different industries. Having access to such data can help provide the insights needed to make complex business decisions. That is why it is important to know how to find and use satellite imagery data. It may be the notch required to get an edge over your competitors.
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