Approach to calculate values using Statistical Info

Hi,

I am assuming that values that I get using Statistical Info are based on pixel values (i.e., point value) in data sets, not areal mean values including the fractional intersection between each pixel polygon and my area of interest represented in GeoJSON. However, I would like to make sure if that is true.

For example, I uploaded a GeoJSON for a city and ran a Statistical Info task. After processing, I could download a CSV file that contains a column named “C0/mean.” I would think this column contains average values in pixels as point measurement within the boundary of the GeoJSON file. Can anyone please confirm this? Area vs point values are important for me because I am using S5P.

In addition, I don’t see any values for C0/median, C0/p10, and C0/p90. Does anyone know why?

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Hi @byeonguk.kim,

The response of statistical api is the point measurement as you expected.

The default statistical info contains the min, the max, the mean, and the standard deviation only. If you would like to have median, p10, and p90 you could specify the “percentiles” as a parameter. For more information and examples please refer to our Statistical API documentation.

Best regards,

Chung

Hi @byeonguk.kim ,

if you are using S5p (which is hosted at CreoDIAS), you won’t yet be able o use the new Statistical api that Chung mentioned. You will have to tweak your fis request in order to get C0/median, C0/p10, and C0/p90:

Add &BINS=10&TYPE=EQUALFREQUENCY to your request so that your request looks something like:
https://creodias.sentinel-hub.com/ogc/fis/<your-configuration-instnace-id>?LAYER=NO2&CRS=CRS:84&BBOX=3.386459,32.731841,12.787389,41.917096&WIDTH=512&HEIGHT=594&TIME=2021-03-26/2021-04-26&BINS=10&TYPE=EQUALFREQUENCY

this will return histogram with equal number of samples in each bin. C0/p10 is the value of lowerEdge of the second bin, C0/p90 is the value of lowerEdge of the last bin and C0/median is the value of lowerEdge of the 6th bin.