"""Importer for RES2DINV files
Please note that this importer is very rudimentary at the moment. We need test
data and real usage to improve upon this.
"""
from io import StringIO
import logging
import pandas as pd
from reda.utils.electrode_manager import electrode_manager
logger = logging.getLogger(__name__)
[docs]
def import_res2dinv(filename, **kwargs):
""" Read a RES2DINV-style
Parameters
----------
Returns
-------
data : :py:class:`pandas.DataFrame`
Contains the measurement data
elec_mgr : :py:class:`reda.utils.electrode_manager.electrode_manager`
Electrode manager that manages the electrode positions
topography : None
No topography information is contained in the text files, so we always
return None
"""
# each type is read by a different function
importers = {
# general array type
11: _read_general_type,
}
file_type, content = _read_file(filename)
if file_type not in importers:
raise Exception(
'type of RES2DINV data file not recognized: {0}'.format(file_type)
)
header, data, elec_mgr = importers[file_type](content)
topography = None
return data, elec_mgr, topography
def _read_file(filename):
"""
Read a res2dinv-file and return the header
Parameters
----------
filename : str
Data filename
Returns
------
type : int
type of array extracted from header
file_data : :py:class:`StringIO.StringIO`
content of file in a StringIO object
"""
# read data from file
with open(filename, 'r') as fid2:
abem_data_orig = fid2.read()
# for easy access, store the data in a StringIO container
fid = StringIO()
fid.write(abem_data_orig)
fid.seek(0)
# determine type of array
fid.readline()
fid.readline()
file_type = int(fid.readline().strip())
# reset file pointer
fid.seek(0)
return file_type, fid
def _read_general_type(content):
"""Read a type 11 (general type) RES2DINV data block
Parameters
----------
content : :py:class:`StringIO.StringIO`
Content of data file
Returns
-------
"""
header_raw = []
index = 0
while index < 9:
line = content.readline()
# filter comments
if line.startswith('//'):
continue
else:
header_raw.append(line.strip())
index += 1
# parse header
header = {
'name': header_raw[0],
# unit is meters?
'unit_spacing': float(header_raw[1]),
'array_type': int(header_raw[2]),
'type2': int(header_raw[3]),
'type_of_measurements': int(header_raw[5]),
'nr_measurements': int(header_raw[6]),
'type_of_x_location': int(header_raw[7]),
'ip_data': int(header_raw[8]),
}
if header['type_of_measurements'] == 0:
raise Exception('Reading in app. resistivity not supported yet')
df = pd.read_csv(
content,
delim_whitespace=True,
header=None,
names=(
'nr_elecs',
'x1',
'z1',
'x2',
'z2',
'x3',
'z3',
'x4',
'z4',
'value',
),
nrows=header['nr_measurements'],
)
# type of x-location
# 0: true horizontal distance
# 1: true horizontal distance
# 2: surface distance
elec_mgr = electrode_manager()
# for now ignore the z coordinates and compute simple electrode denotations
df['a'] = df['x1'] / header['unit_spacing'] + 1
df['b'] = df['x2'] / header['unit_spacing'] + 1
df['m'] = df['x3'] / header['unit_spacing'] + 1
df['n'] = df['x4'] / header['unit_spacing'] + 1
# for now assume value in resistances
df['r'] = df['value']
# ABMN are integers
df['a'] = df['a'].astype(int)
df['b'] = df['b'].astype(int)
df['m'] = df['m'].astype(int)
df['n'] = df['n'].astype(int)
# remove any nan values
df.dropna(axis=0, subset=['a', 'b', 'm', 'n', 'r'], inplace=True)
# drop unused columns
df.drop(
[
'nr_elecs',
'x1', 'z1',
'x2', 'z2',
'x3', 'z3',
'x4', 'z4',
'value',
], axis=1, inplace=True
)
return header, df, elec_mgr
