mlossp 2.2.1

A package to spatially join and concatenate Satellite data into time series.

Satellite Data Preprocessor

A package built for preprocessing netCDF, netCDF4, GeoJSON, or atomic CSV files using spatial joins and concatenation to create time-series numpy and csv datasets.

Keyword Arguments

Kwarg	Description
extra_config	Path to the configuration file used for loading nc files. (Only provide this if you are loading netCDF or CSV files.
record_out	A function to generate a label from a file name.
region_out	A function to generate a label from a region file name.
suffix_out	A function that returns a string to be appended to the output file.

Usage:

• Define a directory structure and create the required configuration files. (see Configuration Files)
• Create an instance of Preprocessor and provide the path to a config json file along with keyword arguments.
• Call Preprocessor.preprocess to preprocess data according to the provided config.
• To define configurations for different data sources, use Preprocessor.preprocess_multi. Config_list[i] and Kwargs_list[i] will apply to the ith data source.

import mlossp as sp

config_path = "config.json"
extra_config_path = "nc_config.json"
f = lambda : "_1"

preprocessor = sp.Preprocessor(
    config_path,
    extra_config=extra_config_path,
    suffix_out=f
)
preprocessor.preprocess()

config_list = ["config_1.json", "../configs/config_2.json"]
kwargs_list = [{"extra_config": extra_config_path, "out_out": f}, {}]
preprocessor.preprocess_multi(config_list, kwargs_list)

Configuration Files

Every category of data, i.e., data within a directory should have a json configuration file. The following keys should be defined within the configuration file:

Key	Description	Optional
regions_dir	The path to the directory where the geographical data is stored	No
data_dir	The path to the directory where the satellite data is stored	No
out_dir	The path to the directory where the output files will be stored	No
crs	A geopandas supported coordinate reference system	Yes
regions_file_map	A mapping of region name to their file path	No
selected_regions	The list of regions to extract from the satellite data. Must be in regions_file_map.	No
join_on	The feature that duplicate data entries in a timestamp will be aggregated on	No
joins	The aggregate metrics that will be stored from join_on's aggregation.	No
file_extension	The format of all data being layered. Can be one of *.pkl, *.json, *.geojson, *.nc4, or *.nc	No
compress_to	The path to the directory where visualization files will be stored.	Yes
chunk	This will aggregate every chunk files together. E.g. 365 chunked into 7 will result in 53 chunks.	Yes

Given the following directory structure:

- Data
    - Visualizations
    - EO
        - data1.nc
        - data2.nc
    - EO_OUT
    - Countries
        - gadm41_LKA_1.json
        - gadm41_USA_1.json
- preprocesser.py

And region and satellite data with the following features:

Region: NAME, NAME_1, NAME_2, POINT, ...
Satellite Data: longitude, latitude, precipitationCal, ...

A sample configuration would be defined as follows:

{
  "compress_to": "Data/Visualizations",
  "crs": "EPSG:4326",
  "regions_dir": "Data/Countries",
  "data_dir": "Data/EO",
  "out_dir": "Data/EO_OUT",
  "regions_file_map":  {
    "Sri Lanka": "gadm41_LKA_1.json",
    "USA": "gadm41_USA_1.json"
  },
  "selected_regions": ["Sri Lanka"],
  "join_on": "NAME_1",
  "joins": {
    "precipitationCal": ["mean", "min", "max"]
  },
  "file_extension": "*.nc",
  "chunk": 5
}

Preprocessing netCDF data

To use this package with netCDF data, a separate configuration must be provided for each data source. A sample configuration is shown below.

{
	"latVar":"latitude",
	"lonVar":"longitude",
	"is360":false,
	"extraVars": ["NDVI"]
}

Configuration Keys:

Key	Description
latVar	The name of the latitude column
lonVar	The name of the longitude column
is360	Set to true if the netCDF contains data within 0 - 360 degrees
extraVars	Desired features to be retrieved from the netcdf file.

Preprocessing CSV data

To use this package to preprocess CSV data, a configuration file must be defined for each data source. CSV data provided will be aggregated across the given time period; Information across higher temporal resolutions will be lost.

The number of csv files provided will be the final number of timestamps. If you would like to atomicize your csv files, see [Formatting CSVs](#Formatting CSVs).

{
	"latVar":"Lattitude",
	"lonVar":"Longitude",
	"is360":false,
	"filter": [["Disease Name", "Dengue Fever", "e"], ["Location Name", "SRILANKA", "n"], ["Location Name", "Kalmune", "n"]],
	"extraVars": ["Cases", "Location Name"]
}

Configuration Keys:

Key	Description
latVar	The name of the latitude column
lonVar	The name of the longitude column
is360	Set to true if the longitude and latitude are measured in 360 degrees
filter	A list of length 3 arrays of [Column Name, Target Value, Equals (e) or Not Equals (n)]. All rows whose column name has a value that is either equal or not equal to the target will be excluded.
extraVars	Features to keep in the output.

Formatting CSVs

CSVs are inherently designed to support tabular, 2D data. Hence, storing higher-dimensional data such as tensors and ndarrays as CSVs results in inconsistent formats.

We offer mlossp.formatters as a solution to parse a (or a list of) 3D CSV files into a 3D numpy tensor, which is formatted then written into a .npy file and a .csv file that is supported by align_csv and align_npy.

Citations

This package incorporates modified code from https://github.com/podaac/netcdf_to_geojson_vectors, which is licensed under Apache 2.0. You may obtain a copy of the license at: http://www.apache.org/licenses/LICENSE-2.0.