Subset Processes of Flyingpigeon

Subset process as ipython notebook:


The WPS flyingpigeon provides several processes to perform spatial subsetts of netCDF files. This are:

  • bounding box: reduces the input netCDF files to a given latitude longitude bounding box.

  • country or continent subset: to reduce netCDF files to only the intersection of selected polygons. Countries and Continents are predifined.

  • WFS subset: reduce netCDF files to only the intersection of given polygons available on a given WFS server.

# import the WPS client and connet to the server
from birdy import WPSClient
import birdy

fp_server = 'http://localhost:8093/wps'   # finch

# simple connection (not recommended for larger processing)
fp = WPSClient(fp_server)

# asyncron connection with progess status requests
fp_i = WPSClient(url=fp_server, progress=True)

Explore the available processes:

# fp? for general exploration on processes provided by flyingpigeon

# of check out a process in detail:
help(fp.subset_continents) # or type: fp.subset_countries?
Help on method subset_continents in module birdy.client.base:

subset_continents(resource=None, region='Africa', mosaic=False) method of birdy.client.base.WPSClient instance
    Return the data whose grid cells intersect the selected continents for each input dataset.

    region : {'Africa', 'Asia', 'Australia', 'North America', 'Oceania', 'South America', 'Antarctica', 'Europe'}string
        Continent name.
    mosaic : boolean
        If True, selected regions will be merged into a single geometry.
    resource : ComplexData:mimetype:application/x-netcdf, application/x-tar, application/zip
        NetCDF Files or archive (tar/zip) containing netCDF files.

    output : ComplexData:mimetype:application/x-netcdf
        NetCDF output for first resource file.
    metalink : ComplexData:mimetype:application/metalink+xml; version=4.0
        Metalink file with links to all NetCDF outputs.
# point out some input files:

url1 = 'https://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/ncep.reanalysis.dailyavgs/surface/slp.2000.nc'
url2 = 'https://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/ncep.reanalysis.dailyavgs/surface/slp.2001.nc'
url3 = 'https://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/ncep.reanalysis.dailyavgs/surface/slp.2002.nc'
url4 = 'https://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/ncep.reanalysis.dailyavgs/surface/slp.2003.nc'

Call a continent subset process

All netCDF input files will be subsetted seperatly and depending on mosic=True or Fales the selected polygons are given as seperated files or one output file per input file including one intersection of all selected polygons.

subset_countries is working in the same principe

# run the process
out = fp_i.subset_continents(resource=[url1, url2, url3, url4], region=['Europe', 'Africa'], mosaic=True)

# You need to wait until the processing is done!
HBox(children=(IntProgress(value=0, bar_style='info', description='Processing:'), Button(button_style='danger'…

There are two outputs: * a netCDF file to have a quick test to check if the process went according to the users needs * a metalink file with the list of all output files

# check the output files:
# plot the test file with the flyingpigeon plot function
out = fp_i.plot_map_timemean(resource=out.get()[0])
HBox(children=(IntProgress(value=0, bar_style='info', description='Processing:'), Button(button_style='danger'…
# the plot process returnes one graphic file
from IPython.display import Image
from IPython.core.display import HTML
Image(url= out.get()[0], width=400)