ee-satellites 0.0.1

A Python library that allows to extract data from satellites, exploiting machine parallelism and relying on Google Earth Engine APIs.

ee-satellites

This library provides an easy-to-use, comprehensive, and flexible way to work with satellites data (for now: S1_GRD, S2_SR and LANDSAT8_T1_TOA). Its key advantages include: a well-documented API, support for the mainly used satellites, open-source code, and regular updates.
In addition to the already mentioned advantages, the implemented code relies on Google Earth Engine (GEE) APIs (used to access satellites data and perform some tasks such as cloud masking, image compositing, and time series selection) and exploits multi-threading (designed to work efficiently, by making a lot of parallel I/O requests to GEE).

These advantages make it an excellent tool for anyone working with satellites data, since it allows to generate datasets that can be both easily used for data analysis and efficiently integrated with well-known ML libraries, to deploy models.

How to install it?

$ pip install ee-satellites

This library is composed of lot of functions, the main ones are here described.

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get_features() function

It allows to get from an input pandas DataFrame composed of fields information, an output DataFrame that contains for each time selected satellites (sentinel-1, sentinel-2 or landsat-8) passed over the specified fields, within a given time period, all the mean values of some of the most used indexes (optical or radar).

The filters_params parameter is a list (default: None) containing the values of the Earth Engine filters to be used for extracting Image Collections, with the specified sentinel satellites. For Sentinel-2 the first parameter in the list is the value of the CLOUDY_PIXEL_PERCENTAGE filter (LESS OR EQUAL TO - values in range [0, 100]), whereas for Sentinel-1 the first parameter in the list is the value of the orbitProperties_pass filter (ASCENDING or DESCENDING).

The fields_threads parameter (default: 4) is the number of threads to dedicate to parallelization of requests over the fields level, the remaining part instead is used to apply parallelization over dates level. The value of this parameter should be high (with respect to the overall number of threads exploitable) if you have a lot of fields but a little time-span to consider, whereas if you have fewer fields but a bigger time-span you should decrease this parameter. Finally, if you have lot of fields with lot of dates to process it should may be optimal considering half of the overall number of threads available.
A correct choice of this parameter can drastically reduce the features extraction time.

See the code for a better understanding.

Input DataFrame

The input DataFrame, lets suppose named fields_df, should be structured as follows (just columns position matters):

field_name	polygon_coordinates
P-BLD	[(-4.202723286616649, 43.39683579015289), (-4...]
P-BLLT1	[(-4.085622203603083, 43.429605845026266), (-4...]
P-BLLT2	[(-4.084840437376829, 43.430826294936246), (-4...]
P-CBRCS1	[(-4.200826431306206, 43.39067464298489), (-4....]
...	...
P-VNS	[(-4.151167740565273, 43.40535762666503), (-4....]

How to execute it?

First you have to initialize and authorize the Google Earth Engine APIs.

import ee, ee_satellites

ee.Authenticate()
ee.Initialize()

Then, supposing that you have already loaded the fields_df pandas DataFrame, you have just to run the following code. Change the satellite parameter value in case you want sentinel-1, or landasat-8, indexes extracted for the fields specified (within the time period selected - be careful that the given date format is consistent with ISO 8601 notation). See the above general description, instead, to comprehend what filters_params and fields_threads parameters are useful for.

df = sentinel_satellites.get_features(fields_df, '2022-01-01', '2022-12-31', satellite='sentinel-2', filters_params=['40'], fields_threads=3)

Output DataFrame

The output generated DataFrame, namely df, will be structured as follows:

field_name	s2_acquisition_date	B1	B2	B3	...	MCARI2	BSI	GLI	ALTERATION	SDI
P-BLD	2022-01-06	2.260204	119.981293	550.044218	...	0.922907	6282.955014	0.513069	2.131255	3484.508503
P-BLD	2022-01-16	13.785714	111.540816	528.481293	...	0.921371	6545.200602	0.517949	2.127614	3636.382653
...	...	...	...	...	...	...	...	...	...	...
P-VNS	2022-11-17	1133.057399	1364.994619	1726.755157	....	0.594553	11195.020251	0.070841	1.441033	1939.695067
P-VNS	2022-12-17	955.040359	1208.792825	1617.324664	...	0.688394	10547.592756	0.107797	1.505526	2913.218834

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What's new?

• version: 0.0.1:
  • This libary comes from the old one (named sentinel-satellites) where Landsat-8 indexes have been added