obspy.clients.fdsn.mass_downloader.domain.Domain¶

class Domain[source]¶

Bases: builtins.object

Abstract base class defining a domain - subclass it to define a new domain.

Each subclass must implement the get_query_parameters() method and optionally the is_in_domain() method which enables the construction of arbitrarily complex domains. The get_query_parameters() method must return the query parameters to download as much data as required. The is_in_domain() can later be used to refine the domain after the data has been downloaded.

It can be thought of as a boolean operation - first the rough domain is specified including all the possible points, then some points are removed again. This is illustrated with an example domain representing Germany utilizing the external packages shapely and fiona. Shapefiles can be found online on many websites, for example on http://www.gadm.org/. The example works by first extracting the bounds of the country to formulate the FDSN query and then removing points outside of the exact shape.

import fiona
import shapely.geometry

from obspy.clients.fdsn.mass_downloader import Domain


class Germany(Domain):
    def __init__(self):
        Domain.__init__(self)

        fiona_collection = fiona.open("./DEU_adm/DEU_adm0.shp")
        geometry = fiona_collection.next()["geometry"]

        self.shape = shapely.geometry.asShape(geometry)
        self.b = fiona_collection.bounds

    def get_query_parameters(self):
        return {"minlatitude": self.b[1],
                "minlongitude": self.b[0],
                "maxlatitude": self.b[3],
                "maxlongitude": self.b[2]}

    def is_in_domain(self, latitude, longitude):
        if self.shape.contains(shapely.geometry.Point(longitude,
                                                      latitude)):
            return True
        return False

This is further illustrated by the following image. The green rectangle denotes the original FDSN query which returns the blue points. In the second step the red points are discarded leaving only points (stations) within Germany.

Attributes

__abstractmethods__	frozenset() -> empty frozenset object
__dict__
__doc__	str(object=’‘) -> str
__module__	str(object=’‘) -> str
__weakref__	list of weak references to the object (if defined)

Public Methods

get_query_parameters	Return the domain specific query parameters for the
is_in_domain	Returns True/False depending on the point being in the domain.

Special Methods

__dir__	default dir() implementation
__format__	default object formatter
__new__	Create and return a new object.
__reduce__	helper for pickle
__reduce_ex__	helper for pickle
__sizeof__	size of object in memory, in bytes
__subclasshook__	Abstract classes can override this to customize issubclass().