I guess we will look back on 2020 as a very special period, since this year was everything but normal, due to the COVID-19 pandemic. Many of us have faced new challenges, radical changes in their lives and financial insecurity, but this period has provided a great opportunity for renewal as well.
Satmapper.hu is one of the products of this renewal. The site was launched in June this year with the aim of promoting the possibilities of remote sensing data provided by the Copernicus program, which can even be incorporated into a digitized “smart village / city” concept. Enoght said, let’s have a look on the data of 2020.
Not all satellite images are cloudless ...
When Satmapper started, the first few published satellite images focused on the village of Kiszombor, however the list was soon expanded with the admnisitrative areas of Makó. Both of these areas are great example for the development of data provision, as they have agricultural lands, forests, lakes and rivers and the hours of sunshine is also high in these areas. The latter is especially important for the Sentinel-2 satellites, as these satellites do not see through the clouds, therefore if a satellite image is covered with more than 30% by clouds, unfortunately that image will be unusable.
The pie chart below shows that only 37% of all Sentinel-2 satellite images taken in 2020, including Kiszombor and Makó, had low cloud cover, while the remaining 63% were too cloudy.
On a monthly basis, an average of 12 satellite datasets were crated of the examined administrative areas, of which an average of 4 were usable. The exact monthly distribution is illustrated in the bar chart and table below.
It is important to note that the values above apply to the area / mosaic 34TDS.
How did Kiszombor change in 2020?
As in 2019, an animation was created from the regularly collected satellite images, which helps to observe the changes within the administrative areas of Kiszombor. (High-resolution animations can be downloaded from the link below the images.)
The NDWI index, which can be used to examine larger areas of lakes, rivers and inland waters, changed in 2020 as follows. Note the islands in the iver Maros, which appear at low water levels, typically around August-September.
With the help of the NDVI index, we can get information about the vegetation status of plants, crops and it can help us identify healthy and stressed areas. The animation below shows how the vegetation develops in each agricultural area and how it disappears suddenly due to the harvest. Cutting down of a small area of forest can be seen in the north-western peaks as well. For those who want to better understand the concept of the NDVI index, I recommend one of the previous blog posts.
Finally, let’s have a look at the NDMI index, which can be used to examine the moisture content of the surface or to locate areas that are currently dry or at risk from fire point of view. This was as follows in 2020.
How did Makó change in 2020?
After Kiszombor, let’s see how the administrative area of Makó changed in 2020.
The NDWI index for Makó is not very exciting, as only a few lakes emerge northeast of the city, and their condition has not changed much over the months.
The change in the NDMI index clearly shows that very active agricultural activity took place within the administrative boundaries of Makó in 2020.
Finally, let us look at the NDMI index as well. Dry, vegetation-free areas (marked in red) that can be noticed at the beginning and end of 2020, are well visible.
Well, that’s pretty much how the year 2020 looked like through the eyes of Sentinel-2 satellites. If someone wants to better understand the meaning of the above indexes (NDWI, NDVI, NDMI), I recommend the short descriptions on the Satmapper homepage, as well as the blog section where you can read more articles on using satellite remote sensing.
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