Why do I need Earth observation data processing?
While our eyes only detect a fraction of all light available, satellite sensors can actually capture – and send back – much more information. Furthermore, this information is relayed back to us in a format quite different from the photographs we are used to. For each band, satellites capture the spectral reflectance of the area within a specific narrow band of the light spectrum.
True-colour composite images use the red, green, and blue bands gathered by satellites to mimic the range of vision for the human eye, showing us images closer to what we would expect to see in a normal photograph.
Satellites also capture information in the non-visible part of the light spectrum. Different features: rock, bare soil, vegetation, burned ground, snow, sediment-rich water, etc. all have different reflectance properties in each band. This a called a 'spectral signature'.
To highlight specific features, one or more of the RGB bands can be substituted for another, such as infrared, or near infrared, which are not visible to the human eye. These images are referred to as false-colour images.
Additionally, to better discriminate between features and highlight changes in time, mathematical models can be applied to the data to produce a new kind of processed image. These are referred to as indexes.
When should I use MSAVI?
The Modified Soil Adjusted Vegetation Index (MSAVI) algorithm was was developed by Qi et al. (1994). The adjustment factor L for SAVI depends on the level of vegetation cover being observed. The basic idea of MSAVI was to provide a variable correction factor L. The correction factor used is based on the product of NDVI and WDVI. This means that the isovegetation lines do not converge to a single point.).
How to obtain MSAVI data using EarthCache
Note: If you do not have an account, you can sign up for one here.
To obtain a true-colour image using EarthCache, simply select MSAVI processing as an output when creating or editing a pipeline through the dashboard.
To obtain a true-colour image using code, you can create or edit a pipeline using the following parameters: