Satellite Imagery for Everyone: Resources and Interpretation

Satellite imagery is the process of taking images of the earth’s surface using satellites or manned aircraft. Humans have sent numerous satellites to space for various purposes, which is why satellite devices may be built differently. Every satellite is equipped with sensors that pick up EM waves. Passive sensors pick up EM waves from the sun that is reflected by structures on the earth. On the other hand, active sensors emit radiation and perceive the waves that have been reflected by the earth. The advantage that active sensors have over passive ones is that they though out the year and at any time of the day to capture satellite pictures of earth.

Sensors on satellites can perceive several types of electronic and magnetic waves such as UV light, infrared, microwaves, etc. On a satellite picture, the sections captured by the invisible light spectrum are assigned with visible color. It ensures that the pictures are clear and visible.

Real time satellite imaging can be used to identify different objects on earth because each surface reacts to EM radiation differently. For example, smooth objects will reflect most of the light it comes in contact with in one direction. On the other hand, rough surfaces like trees will reflect light in different directions. Satellites take advantage of these properties to be able to measure forest density, plant health, and soil water levels.

Global Forest Watch uses pictures taken by Landsat satellites to monitor how the forest changes over time. NASA originally started and launched the first Landsat satellite to take pictures of the earth at regular intervals. However, with time, people have found the use of satellite data in our everyday life, such as to monitor the weather, forest cover, air quality, water sources, agricultural fields, etc. Also, images taken by Landsat satellites are used across different industries such as mapping, geography, agriculture, mining, forestry, city planning, etc.

Best Satellite Resources and Maps

Landviewer

Landviewer is a satellite-driven platform created by EOSDA which allows users to search, view, process, and download satellite data. Also, they can apply over ten different indices present in the tool to get accurate insights from satellite imagery to solve real business problems. In addition to the default indices, users can also create custom ones by combining different spectral bands.

Users have access to 10 medium-resolution satellite images per day for free from multiple sources such as Landsat 8 OLI + TIRS, Sentinel-2 L2A, CBERS-4 MUX, etc. Also, high-resolution pictures are available for purchase, gotten from satellites such as TrippleSate, SuperView, KOMPSAT-3, Gaofen 2, and a host of others. Users can obtain some of the most up to date satellite images of earth with LandViewer.

With this tool, users can get and process images of their area of interest from any part of the globe. A prominent advantage of this platform is that users can compare images of their area of interest taken on different dates, times of the day, and from different satellites using the time series analysis and split view mode feature.

Mapbox

Mapbox created and still significantly contributes to open-source mapping. Their data is gotten from open sources such as NASA and OpenStreetMap.

Bing Maps

This platform is built by Microsoft, and it provides satellite imagery, Streetside, and has almost the same features like Google maps. It provides users with different views of the earth’s surface.

Here Maps

This is a tech company that offers mapping and location data. Their services are often used by people and businesses that provide automotive services.

Terra Fly

They provide high-res satellite pictures in 2D and 3D and historical imagery, which are available for download.

Cesium

This platform has been used to build one of the best 3D world maps. It is user-friendly and provides high-quality visual content. Users can build their own custom 3D map.

Free Street View

This is a platform that allows users to discover cities. All you users need to do is enter the name of any city or address to start exploring.

Live Map of Satellite Positions

As the name suggests, this is a platform that provides the current location of all satellites that surround the earth.

Live Current & Wind Surface

It is a platform that provides a live satellite view of wind surface, direction, mode, speed, and height.

Stuff in Space

This tool shows a constantly updated 3D map of objects that surround the earth.

Interpretations

Images taken by satellites hold lots of important information when you can interpret them. The pictures can show you crop health, how much an urban area has changed, and even the extent of damage done by disasters. So, when interpreting satellite pictures, start with these five steps:

• Find the scale
• Detect shapes, patterns, and texture
• Define the colors
• Find north
• Take into account your prior knowledge

Now, let’s look in detail at the first step of satellite image interpretation, which is to determine scale.

When trying to interpret satellite images of earth, you should first look for familiar places on the map. Most people go to their house, university or workplace. Some satellites can produce high-resolution images where the user can identify houses and even cars.

Scaling satellite pictures can be quite useful. For example, in cases of wildfire, a high-resolution image can show you which houses will be affected the most. As you scale the image, you will begin to see how the whole region will be affected by the fire.