Stand-alone Python scripts are those that can be run directly from the Python interpreter. Such a script will create a Geosoft context by calling geosoft.gxpy.gx.GXpy(), followed by further use of the geosoft.gxpy and geosoft.gxapi module interfaces. See Hello World#StandAlone, which provides a simple example as part of the Python Tutorial.
Following is a sample script that will add a value to a channel of a database (https://github.com/GeosoftInc/gxpy/blob/master/examples/stand-alone/chanadd.py):
"""
Add a constant value to a channel on all selected lines.
This is a sample Python program that illustrates how to connect to the GX
developer environment from a stand-alone program.
Follwoing are the basic steps:
1. Get (create) a GX Object handle.
2. Collect command-line parameters
3. Open the database
4. Process the data
"""
import os
import sys
import argparse as argp
import geosoft.gxpy as gxpy
def rungx():
raise Exception("This is not an extension. Please use a python interpreter.")
def process_database(db, channel_name, add_value):
"""
Process all selected lines in a database by adding a constant
value to a channel. The data is processed in-place.
"""
# work through the data a line at a time - get a list of selected lines
print('Processing selected lines...')
lines = db.list_lines()
# for each line, get the data, add a value, return the data to the line
for l in lines:
# print to the console to reflect progress
print('line {}...'.format(str(l)))
# get the data and determine the dummy to the data type
data, ch, fid = db.read_line(l, channels=channel_name)
dummy = gxpy.utility.gx_dummy(data.dtype)
# make a dummy mask so we can replace dummies after processing
dMask = gxpy.utility.dummy_mask(data)
# process - add the value, then replace the dummies
sum = data + add_value
sum[dMask] = dummy
# write the data back to the database
db.write_channel(l, channel_name, sum, fid)
if __name__ == "__main__":
gxpy.utility.check_version('9.2')
# get (create) a GX context
with gxpy.gx.GXpy() as gxp: # get the current gx context
# The GX_GEOSOFT_BIN_PATH Environment variable should contain a path with geodist.dll
print("GX_GEOSOFT_BIN_PATH: {}".format(os.getenv("GX_GEOSOFT_BIN_PATH")))
print('Working directory: ' + os.path.abspath(os.curdir))
print('User: {}'.format(gxp.gid))
# get command line parameters
parser = argp.ArgumentParser(description="Add a constant to a Geosoft database channel")
parser.add_argument("sDB", help="Geosoft database")
parser.add_argument("sCh", help="channel to process")
parser.add_argument("-v",
"--value",
type=float,
default=1.0,
help="value to add, default is 1.0")
args = parser.parse_args()
# echo parameters
print("\nDatabase = "+args.sDB)
print("Channel = "+args.sCh)
print("Value to add = {}\n".format(args.value))
# open the database
with gxpy.gdb.Geosoft_gdb.open(args.sDB) as db:
# process the data
process_database(db, args.sCh, args.value)
To run this "stand-alone" script from the command-line:
python chanadd.py --help
usage: chanadd.py [-h] [-v VALUE] sDB sCh
Add a constant to a Geosoft database channel
positional arguments:
sDB Geosoft database
sCh channel to process
optional arguments:
-h, --help show this help message and exit
-v VALUE, --value VALUE
value to add, default is 1.0
python chanadd.py mydata.gdb dem -v 100