If you want to track changes in the The Amazon forest, seeing the full extent of a hurricane or figuring out where people need help after a disaster is much easier to do with the sight of a Satellite in orbit around a a few hundred kilometers above the Earth.
Traditionally, access to satellite data was limited to researchers and professionals with expertise in remote sensing and image processing. However, the increasing availability of open access data from government satellites such as Landsat and Sentinel, and free cloud computing resources such as Amazon Web Services, Google Earth Engine and Microsoft Planetary Computer, has made it possible for almost anyone to Gain insight into ongoing environmental changes.
I working with geospatial big data as a teacher. Here’s a quick overview of where you can find satellite imagery, as well as free and fairly simple tools anyone can use to create time-lapse animations from satellite imagery.
For example, planners and planners – or people considering a new home – can monitor the weather how the rivers movedconstruction slipped into Wilderness areas or an eroded coastline.
Environmental groups can monitor deforestation, the effects of climate change on ecosystems, and how other human activities like irrigation are shrinkage of water bodies as Aral Sea in Central Asia. And disaster managers, aid groups, scientists and anyone interested can monitor natural disasters such as volcanic eruptions And Forest fires.
Putting Landsat and Sentinel to work
More than 8,000 satellites are in orbit Earth Today. You can see a live map of them at keeptrack.space.
Some transmit and receive radio signals for communications. Others provide Global Positioning System (GPS) services for navigation. The ones that interest us are the Earth observation satellites, which collect images of the Earth, day and night.
Landsat: Earth’s longest satellite mission, Landsathas been collecting images of the Earth since 1972. The last satellite in the series, Landsat 9was launched by NASA in September 2021.
In general, Landsat satellite data has a spatial resolution of about 100 feet (about 30 meters). If you think of the pixels in a magnified photo, each pixel would be 100 feet by 100 feet. Landsat has a temporal resolution of 16 days, which means that the same location on Earth is photographed approximately once every 16 days. With Landsat 8 and 9 in orbit, we can get global coverage of Earth once every eight days. This facilitates comparisons.
Landsat data has been accessible to the public free of charge since 2008. During the 2022 Pakistan floodscientists used Landsat data and free cloud computing resources to determine the extent of the flood and estimate the total flooded area.
Sentinel: Sentinel Earth observation satellites have been launched by the European Space Agency (ESA) as part of the Copernicus program. The Sentinel-2 satellites have been collecting optical images of Earth since 2015 at a spatial resolution of 10 meters (33 feet) and a temporal resolution of 10 days.
GOES: The images you’ll most often see in US weather forecasts are from NOAA’s geostationary operational environmental satellites, or GOES. They orbit above the equator at the same speed the earth rotatesso they can continuously monitor the Earth’s atmosphere and surface, providing detailed information about weather, climate, and other environmental conditions. GOES-16 And GOES-17 can image the Earth at a spatial resolution of about 1.2 miles (2 kilometers) and a temporal resolution of five to 10 minutes.
How to create your own visualizations
In the past, creating a Landsat time-lapse animation of a specific area required extensive data processing skills and many hours or even days of work. However, nowadays, free and user-friendly programs are available that allow anyone to create animations with just a few clicks in an Internet browser.
For example, I created a interactive web app for my students that anyone can use to quickly generate time-lapse animations. The user zooms in on the map to find an area of interest, then draws a rectangle around the area to save it as a GeoJSON file – a file containing the geographic coordinates of the chosen region. Then the user uploads the GeoJSON file to the web application, chooses the satellite to display and the dates, and submits it. It takes about 60 seconds for the app to produce a time-lapse animation.
There are several other useful tools for easily creating satellite animations. Others to try: Snazzy-EE-TS-GIFan Earth Engine application for creating Landsat animations, and planetary computer exploreran explorer to search and view satellite images interactively.
This article was originally published on The conversation by Qiusheng Wu at the University of Tennessee. Read it original article here.