# -*- coding: utf-8 -*-
# Copyright 2013-2019 Tom Eulenfeld, MIT license
"""
Functions for receiver function profile calculation.
"""
import numpy as np
from rf.util import _add_processing_info, direct_geodetic
_LARGE_BOX_WIDTH = 2000
def _get_box(latlon0, azimuth, length, width=_LARGE_BOX_WIDTH, offset=0):
"""Create a single box."""
from shapely.geometry import Polygon
start = direct_geodetic(latlon0, azimuth, offset)
azis = ((azimuth - 90) % 360, azimuth,
(azimuth + 90) % 360, (azimuth + 180) % 360)
dists = (width/2, length, width, length)
latlon = start
corners = []
for a, d in zip(azis, dists):
latlon = direct_geodetic(latlon, a, d)
corners.append(latlon[::-1])
box = {'poly': Polygon(corners),
'length': length,
'pos': offset + length/2,
'latlon': direct_geodetic(start, azimuth, length/2)}
return box
[docs]def get_profile_boxes(latlon0, azimuth, bins, width=_LARGE_BOX_WIDTH):
"""
Create 2D boxes for usage in `profile()` function.
:param tuple latlon0: coordinates of starting point of profile
:param azimuth: azimuth of profile direction
:param tuple bins: Edges of the distance bins in km (e.g. (0, 10, 20, 30))
:param width: width of the boxes in km (default: large)
:return: List of box dicts. Each box has the entries
'poly' (shapely polygon with lonlat corners), 'length' (length in km),
'pos' (midpoint of box in km from starting coordinates),
'latlon' (midpoint of box as coordinates)
"""
boxes = []
for i in range(len(bins)-1):
length = bins[i+1] - bins[i]
box = _get_box(latlon0, azimuth, length, width, offset=bins[i])
if i == 0:
box['profile'] = {}
box['profile']['latlon'] = latlon0
box['profile']['azimuth'] = azimuth
box['profile']['length'] = bins[-1] - bins[0]
box['profile']['width'] = width
boxes.append(box)
return boxes
def _find_box(latlon, boxes, crs=None):
"""Return the box which encloses the coordinates."""
import cartopy.crs as ccrs
from shapely.geometry import Point
if crs is None:
latlons = [boxes[len(boxes)//2]['latlon']]
latlon0 = np.median(latlons, axis=0)
crs = ccrs.AzimuthalEquidistant(*latlon0[::-1])
pc = ccrs.PlateCarree()
p = crs.project_geometry(Point(*latlon[::-1]), pc)
for box in boxes:
poly = crs.project_geometry(box['poly'], pc)
if p.within(poly):
return box
[docs]@_add_processing_info
def profile(stream, boxes, crs=None):
"""
Stack traces in stream by piercing point coordinates in defined boxes.
:param stream: stream with pre-calculated piercing point coordinates
:param boxes: boxes created with `get_profile_boxes()`
:param crs: cartopy projection (default: AzimuthalEquidistant)
:return: profile stream
"""
stack = {}
for tr in stream:
ppoint = (tr.stats.pp_latitude, tr.stats.pp_longitude)
box = _find_box(ppoint, boxes, crs=crs)
if box is None:
continue
pos = box['pos']
comp = tr.stats.channel[-1]
key = (pos, comp)
if key not in stack:
header = {'box_pos': pos,
'box_length': box['length'],
'box_latitude': box['latlon'][0],
'box_longitude': box['latlon'][1],
'profile_latitude': boxes[0]['profile']['latlon'][0],
'profile_longitude': boxes[0]['profile']['latlon'][1],
'profile_azimuth': boxes[0]['profile']['azimuth'],
'profile_length': boxes[0]['profile']['length'],
'num': 1,
'sampling_rate': tr.stats.sampling_rate,
'channel': '??' + comp}
for entry in ('slowness', 'phase', 'moveout', 'processing'):
if entry in tr.stats:
header[entry] = tr.stats[entry]
stack[key] = tr2 = tr.__class__(data=tr.data, header=header)
if 'onset' in tr.stats:
onset = tr.stats.onset - tr.stats.starttime
tr2.stats.onset = tr2.stats.starttime + onset
else:
tr2 = stack[key]
tr2.data = tr2.data + tr.data
tr2.stats.num += 1
for tr2 in stack.values():
tr2.data = tr2.data / tr2.stats.num
if hasattr(stream, 'iterable'): # support tqdm objects
cls = stream.iterable.__class__
else:
cls = stream.__class__
try:
profile = cls(traces=stack.values())
except TypeError: # stream can be an iterator
from rf import RFStream
profile = RFStream(traces=stack.values())
profile.sort(['channel', 'box_pos'])
profile.type = 'profile'
return profile
