# (X, Y) are on NAD83, UTM Zone 15N
X,Y,Z,mag
330000,6629200,211.055369153511,5535
330050,6629200,210.654999327171,5500
330100,6629200,210.286555185181,5476
330150,6629200,209.952679145607,5479
330200,6629200,209.655742280775,5496
330250,6629200,209.397817201372,5544
etc...

import numpy as np
import geosoft.gxpy as gxpy
import geosoft.gxpy.gdb as gxdb

#create context
gxc = gxpy.gx.GXpy()

# Open csv-format data file and skip the first line, which is a comment line
f = open('mag_data.csv', 'r')
f.readline()

# the second line contains the channel/field names, from which we create a list of channel names
channel_names = f.readline().strip().split(',')

#the rest of the file contains data, which we load into a numpy float array
data = np.loadtxt(f, delimiter=',')

#create a new database from list of channels and numpy data. All data is stored in a single line.
gdb = gxdb.Geosoft_gdb.new('mag_data', overwrite=True)
line_name = gxdb.create_line_name(0, gxdb.LINE_TYPE_RANDOM, 0)
gdb.write_line(line_name, data, channel_names)

# set the coordinate system to 'NAD 83 / UTM zone 15N'
gdb.coordinate_system = 'NAD83 / UTM zone 15N'

# set the mag data units to 'nT'
gxdb.Channel(gdb, 'mag').unit_of_measure = 'nT'

exit()

import numpy as np
import geosoft.gxpy as gxpy
import geosoft.gxpy.gdb as gxdb
import geosoft.gxapi as gxapi

#create context
gxc = gxpy.gx.GXpy()

# Open csv-format data file and skip the first line, which is a comment line
f = open('mag_data.csv', 'r')
f.readline()

# the second line contains the channel/field names, from which we create a list of channel names
channel_names = f.readline().strip().split(',')

#the rest of the file contains data, which we load into a numpy float array
data = np.loadtxt(f, delimiter=',')

#create a new database from list of channels and numpy data. All data is stored in a single line.
gdb = gxdb.Geosoft_gdb.new('mag_data_split', overwrite=True)
line_name = gxdb.create_line_name()
gdb.write_line(line_name, data, channel_names)

# set the coordinate system to 'NAD 83 / UTM zone 15N'
gdb.coordinate_system = 'NAD83 / UTM zone 15N'

# set the mag data units to 'nT'
gxdb.Channel(gdb, 'mag').unit_of_measure = 'nT'

print(list(gdb.list_lines()))     # ['L0']
print(list(gdb.list_channels()))  # ['mag', 'X', 'Y', 'Z']
print(gdb.xyz_channels)           # ('X', 'Y', 'Z')

# split the line into sections knowing lines are E-W, and separated by 200 m.
# see https://geosoftinc.github.io/gxpy/9.2/python/GXDU.html?highlight=split_line_xy2#geosoft.gxapi.GXDU.split_line_xy2

split_line_number_start = gxapi.int_ref()
split_line_number_start.value = 1

# create instances to the lines and channels needed by the split_line_xy2 function
line = gxdb.Line(gdb, 'L0')
x_channel = gxdb.Channel(gdb, 'X')
y_channel = gxdb.Channel(gdb, 'Y')

# lock items as required
line.lock = gxdb.SYMBOL_LOCK_READ
x_channel.lock = gxdb.SYMBOL_LOCK_WRITE
y_channel.lock = gxdb.SYMBOL_LOCK_WRITE

# split the original line into segments, based on a lateral distance tolerance of 100 m.
gxapi.GXDU.split_line_xy2(
    gdb.gxdb,
    line.symbol,
    gxdb.Channel(gdb, 'X').symbol,
    gxdb.Channel(gdb, 'Y').symbol,
    1,
    100.0,
    gxapi.rDUMMY,
    gxapi.DU_SPLITLINE_SEQUENTIAL,
    split_line_number_start,
    1,
    1)

#delete the original line as it is no longer needed
gdb.delete_line('L0')

# print a list of the new lines
print(list(gdb.list_lines()))   # ['L1', 'L2', 'L3', 'L4', 'L5', 'L6', ...

exit()

import geosoft.gxpy as gxpy
import geosoft.gxpy.gdb as gxdb

gxc = gxpy.gx.GXpy()

# open the database, best practice is to use a 'with ...' construct
with gxdb.Geosoft_gdb.open('mag_data_split') as gdb:

    # make a new channel for the output, duplicate properties of 'mag' channel
    new_mag_channel = gxdb.Channel.new(gdb, 'mag_base', dup='mag', replace=True)

    # work through each line
    for line in gdb.list_lines():

        print ('processing line {}'.format(line))

        # read data from the line.
        # The read_channel method returns the data as a numpy array, and the fiducial
        mag_data, fid = gdb.read_channel(line, 'mag')

		# use simple numpy math to subtract 5000, then save to the new_mag_channel
        mag_data = mag_data - 5000
        gdb.write_channel(line, new_mag_channel, mag_data, fid)

exit()

import geosoft.gxpy as gxpy
import geosoft.gxpy.gdb as gxdb
import geosoft.gxapi as gxapi

gxc = gxpy.gx.GXpy()

# open the database, best practice is to use a 'with ...' construct
with gxdb.Geosoft_gdb.open('mag_data_split') as gdb:

    # make a new channel for the output, duplicate properties of 'mag' channel
    new_mag_channel = gxdb.Channel.new(gdb, 'mag_base', dup='mag', replace=True)

    # work through each line
    for line in gdb.list_lines():

        print ('processing line {}'.format(line))

        # read data from the line.
        # The read_channel method returns the data in a geosoft VV
        mag_data = gdb.read_channel_vv(line, 'mag')

        # use Geosoft GXVVU.translate function to subtract 5000.
        gxapi.GXVVU.translate(mag_data.gxvv, -5000, 1)
        gdb.write_channel_vv(line, new_mag_channel, mag_data)

exit()

import numpy as np
import geosoft.gxpy as gxpy
import geosoft.gxpy.gdb as gxdb

gxc = gxpy.gx.GXpy()

# open the database, best practice is to use a 'with ...' construct
with gxdb.Geosoft_gdb.open('mag_data_split') as gdb:

    # make a distance channel
    dist_channel = gxdb.Channel.new(gdb, 'distance', dup='x', replace=True)

    # work through each line
    for line in gdb.list_lines():

        print ('processing line {}'.format(line))

        # read data from the line, returns in a 2D numpy array.
        xy_data, channels_read, fid = gdb.read_line(line, ('x', 'y'))

        # get the first point (x0, y0)        
        x0 = xy_data[0, 0]
        y0 = xy_data[0, 1]
        
        # use numpy array math to calculate distance in a 1D array dist_array
        dist_array = np.sqrt((xy_data[:, 0] - x0)**2 + (xy_data[:, 1] - y0)**2)
        
        # save the distance
        gdb.write_channel(line, dist_channel, dist_array, fid)

exit()