In this final practical guide video, Tobias Reinicke will briefly outline some of the emerging trends in online data services and will provide an example of how easily data can now be accessed and utilised via this new breed of services.

Recap of remote sensing techniques and how EO data is used to infer useful information.

The basic information collected from the satellites is reflected EM energy in various slices across the reflected (optical) and thermal part of the EM spectrum. However this reflected energy in itself isn’t particularly useful – we can turn it into nice images, which are certainly useful for some applications, mapping and land use for example. But to add value and interpret what the satellites are seeing, we use models that relate this reflected radiation to other more general properties of interest – things like vegetation amount and function, crop yield, ocean productivity and so on. This process forms the basis of how we turn satellite data into more generally useful quantitative ‘information’.

Combinations of data are needed to calculate certain quantities from space. For example, for the net primary productivity of a forest (how much carbon is the forest taking up) you need to know about the dynamics of the forest, how it’s changing through the year, the temperature, the water available, and also the nature of the trees (deciduous or evergreen) – so it’s a combination of pre-existing maps, observations over time, and current measurements. By combining the data with the starting conditions, you can understand what is going on dynamically.

Remote sensing can be used for many different applications for which it gives you an indication, without giving a final measurement of what is happening on the surface. However, some of these processes require assumptions to be made along the way. For example, without continuing satellite measurements, it would be very difficult to understand fire patterns in southern Africa. Grassland and savannah regenerate quickly – so without regular imaging the process might not be captured. The frequency of fires is important in the story of the whole landscape, so while the amount of carbon being released might be small, the cycle of fire and recovery is very important to understanding the carbon cycle in that area. The regular changes caused by fire affects which kinds of plants can grow there, and human intervention can add another complication, changing the fire regime in the area by removing certain plants.

Satellite imaging can be used to infer useful information about things that are too small to be resolved directly. For example, large carnivorous animals have a relationship with their habitats and changes in those habitats can be detected from satellite imagery, which can prompt researchers to find out more about what is going on on the ground. Satellite imagery can be used to work on areas where animal habitats and human habitats are in conflict, or where habitats are being constrained because of land use change. Similar patterns are also found in deer populations in Norway.

Featured Educators:

• Tobias Reinicke, independent GIS and EO expert

Featured Data Products and Software Tools:

Astro Digital

EarthCast

Don’t forget you can download the video, transcript and take any quizzes available with the links on the right.