poets.image package

Submodules

poets.image.imagefile module

This module provides functions for converting lonlat-information to pixels in an image file (eg. PNG, TIFF) and for calculating a country bounding box.

poets.image.imagefile.bbox_img(source_file, region, shapefile=None)[source]

Clips bounding box out of image file and returns data as numpy.ndarray

Parameters:

source_file : str

Path to source file.

region : str

Identifier of the region in the shapefile. If the default shapefile is used, this would be the FIPS country code.

shapefile : str, optional

Path to shape file, uses “world country admin boundary shapefile” by default.

Returns:

data : dict of numpy.arrays

Clipped image (grey values).

lon_new : numpy.array

Longitudes of the clipped image.

lat_new : numpy.array

Latitudes of the clipped image.

timestamp : datetime.date

Timestamp of the image.

metadata : dict of strings

Metadata from source netCDF file.

poets.image.imagefile.dateline_country(country)[source]

Min and max longitude for countries that spread across the international dateline.

Returns:

lon_min, lon_max : float

Min and max longitude.

poets.image.imagefile.lonlat2px(img, lon, lat)[source]

Converts a pair of lon and lat to its corresponding pixel value in an image file.

Parameters:

img : Image File, e.g. PNG, TIFF

Input image file

lon : float

Longitude

lat : float

Latitude

Returns:

Row : float

corresponding pixel value

Col : float

corresponding pixel value

poets.image.imagefile.lonlat2px_rearr(img, lon, lat)[source]

Converts a pair of lon and lat to its corresponding pixel value in a rearranged image file (see rearrange_img).

Parameters:

img : Image File, e.g. PNG, TIFF

Input image file

lon : float

Longitude

lat : float

Latitude

Returns:

Row : float

corresponding pixel value

Col : float

corresponding pixel value

poets.image.imagefile.px2lonlat(img, lon_px, lat_px)[source]

Converts two arrays of row and column pixels into their corresponding lon and lat arrays

Parameters:

img : Image file

Image which the pixel values refer to

lon_px : np.array

array of column pixels

lat_px : np.array

array of row pixels

Returns:

lon_new : np.array

List of corresponding longitude values

lat_new: np.array

List of corresponding latitude values

poets.image.imagefile.px2lonlat_rearr(img, lon_px, lat_px)[source]

Converts two arrays of row and column pixels into their corresponding lon and lat arrays

Parameters:

img : Image file

Image which the pixel values refer to (rearranged image)

lon_px : np.array

array of column pixels

lat_px : np.array

array of row pixels

Returns:

lon_new : np.array

List of corresponding longitude values

lat_new: np.array

List of corresponding latitude values

poets.image.imagefile.rearrange_img(img)[source]

Rearranges image so that 0 degree Meridian is on the very left. Used when area around the +- 180 degree Meridian is of interest (eastern Russia, Alaska, New Zealand...).

Parameters:

img : Image File, e.g. PNG, TIFF

Image to be rearranged

Returns:

img : Image file

Rearranged image

poets.image.netcdf module

This module provides functions for loading from and writing to NetCDF4 files.

poets.image.netcdf.clip_bbox(source_file, lon_min, lat_min, lon_max, lat_max)[source]

Clips bounding box out of netCDF file and returns data as numpy.ndarray

Parameters:

source_file : str

Path to source file.

lon_min : float

Min longitude of bounding box.

lat_min : float

Min latitude of bounding box.

lon_max : float

Max longitude of bounding box.

lat_max : float

Max latitude of bounding box.

Returns:

data : dict of numpy.arrays

Clipped image.

lon_new : numpy.array

Longitudes of the clipped image.

lat_new : numpy.array

Latgitudes of the clipped image.

timestamp : datetime.date

Timestamp of image.

metadata : dict of strings

Metadata from source netCDF file.

poets.image.netcdf.get_properties(src_file)[source]

Gets variables, dimensions and time period from a netCDF file.

Parameters:

src_file : str

Path to NetCDF file.

Returns:

variables : list of str

List of variables.

dimensions : list of str

Dimensions of the NetCDF file.

period : list of datetime.datetime

Date of first and last image in source file.

poets.image.netcdf.read_image(source_file, variable, date, date_to=None)[source]

Gets images from a netCDF file.

Reads the image for a specific date. If date_to is given, it will return multiple images in a multidimensional numpy.ndarray

Parameters:

source_file : str

Path to source file.

variable : str

Requested variable of image.

date : datetime.datetime

Date of the image, start date of data cube if date_to is set.

date_to : datetime.date, optional

End date of data cube to slice from NetCDF file.

Returns:

image : numpy.ndarray

Image for a specific date.

lon : numpy.array

Longitudes of the image.

lat : numpy.array

Latgitudes of the image.

metadata : dict of strings

Metadata from source netCDF file.

poets.image.netcdf.save_image(image, timestamp, region, metadata, dest_file, start_date, sp_res, nan_value=-99, shapefile=None, temp_res='dekad')[source]

Saves numpy.ndarray images as multidimensional netCDF4 file.

Creates a datetimeindex over the whole period defined in the settings file

Parameters:

image : dict of numpy.ndarrays

Input image.

timestamp : datetime.datetime

Timestamp of image.

region : str, optional

Identifier of the region in the shapefile. If the default shapefile is used, this would be the FIPS country code.

metadata : dict

NetCDF metadata from source file.

dest_file : str

Path to the output file.

start_date : datetime.datetime

First date of available data.

nan_value : int, optional

Not a number value for dataset, defaults to -99.

shapefile : str, optional

Path to shape file, uses “world country admin boundary shapefile” by default.

temp_res : string or int, optional

Temporal resolution of the output NetCDF4 file, defaults to dekad.

poets.image.netcdf.write_tmp_file(image, timestamp, region, metadata, dest_file, start_date, sp_res, nan_value=-99, shapefile=None)[source]

Saves numpy.ndarray images as multidimensional netCDF4 file.

Parameters:

image : dict of numpy.ndarrays

Input image.

timestamp : datetime.datetime

Timestamp of image.

region : str, optional

Identifier of the region in the shapefile. If the default shapefile is used, this would be the FIPS country code.

metadata : dict

NetCDF metadata from source file.

dest_file : str

Path to the output file.

nan_value : int, optional

Not a number value for dataset, defaults to -99.

shapefile : str, optional

Path to shape file, uses “world country admin boundary shapefile” by default.

poets.image.resampling module

poets.image.resampling.average_layers(image, dest_nan_value)[source]

Averages image layers, given as ndimensional masked arrays to one image

Parameters:

image : numpy.ma.MaskedArray

Input image to average.

Returns:

avg_img : numpy.ma.MaskedArray

Averaged image.

poets.image.resampling.resample_to_gridpoints(source_file, region, sp_res, shapefile=None)[source]

Resamples image to predefined gridpoints.

Parameters:

source_file : str

Path to source file.

region : str

Latitudes of source image.

sp_res : int or float

Spatial resolution of the shape-grid.

shapefile : str, optional

Path to shape file, uses “world country admin boundary shapefile” by default.

Returns:

dframe : pandas.DataFrame

Resampled data with gridpoints as index.

poets.image.resampling.resample_to_shape(source_file, region, sp_res, prefix=None, nan_value=None, dest_nan_value=None, shapefile=None)[source]

Resamples images and clips country boundaries

Parameters:

source_file : str

Path to source file.

region : str

Identifier of the region in the shapefile. If the default shapefile is used, this would be the FIPS country code.

sp_res : int or float

Spatial resolution of the shape-grid.

prefix : str, optional

Prefix for the variable in the NetCDF file, should be name of source

nan_value : int, float, optional

Not a number value of the original data as given by the data provider

dest_nan_value : int or float, optional

NaN value used in the final NetCDF file

shapefile : str, optional

Path to shape file, uses “world country admin boundary shapefile” by default.

Returns:

data : dict of numpy.arrays

resampled image

lons : numpy.array

longitudes of the points in the resampled image

lats : numpy.array

latitudes of the points in the resampled image

gpis : numpy.array

grid point indices

timestamp : datetime.date

date of the image

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