I prepared this modification in order to handle the reading of an OEM file in XML format that has a namespace in it. The modification will remove from the tag the namespace, it is transparent for XML files without namespace.

Describe the bug I've originally came across your samples folder in a google search when looking for other example OEM other than the ones provided in ccsds2czml: https://gitlab.com/jorispio/ccsds2czml/-/tree/master/example

All OEM files in samples/real threw a generic datetime microsecond error, but i could not discern any differences between your OEMs and the sample_OEM generated by ccsds2czml. Their sample_OEM worked fine. Below is the traceback error:

C:\Users\khoohuibo\Desktop\ccsds2czml-master>python -m oacmpy -i LEO_10s.oem -o one_sat.czml -v
Input File : LEO_10s.oem
Output File: one_sat.czml
  File:  LEO_10s.oem
Traceback (most recent call last):
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\__main__.py", line 5, in <module>
    main(sys.argv[1:])
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\oem2czml.py", line 78, in main
    _ccsds2czml(inputfile, outputfile, verbose)
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\oem2czml.py", line 35, in _ccsds2czml
    print(" Simulation time span: {} - {}".format(start, end))
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\datetime\Date.py", line 297, in __str__
    return self.strftime(ISO8601_FORMAT_Z)
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\datetime\Date.py", line 291, in strftime
    return self.datetime.strftime(fmt)
  File "C:\Users\Hubert Khoo\.conda\envs\arcsim\lib\site-packages\oacmpy\datetime\Date.py", line 251, in datetime
    self._datetime = datetime(year=year, month=month, day=day, hour=h, minute=m, second=s, microsecond=ms)
ValueError: microsecond must be in 0..999999

I have attached the sample_object.oem file generated for easier reference sample_object.zip

Steps to Reproduce

1. Download both repositories
2. Run the following code in the root directory of ccsds2czml-master to generate a sample_OEM file

python -m example.single.simple_oem

3. Generate CZML file using sample_object.oem file generated in root directory of ccsds2czml-master, using the code below

python -m oacmpy -i sample_object.oem -o one_sat.czml -v

4. Visualize using Cesium Viewer
5. Attempt to generate CZML file by using OEM file from oem-master/samples/real, (Used LEO_10s and GEO_20s)
6. Obtain traceback error as described

# Insert reproducing code snippet here

Python/Package Version Information Python: [e.g. 3.5.1] oem: [e.g. 1.0.0]

Describe the bug When importing an OEM file in KVN format with a size of 450 MB which contains about 7 years of trajectory data the regex match statement in _from_kvm_oem() immediately hogs > 16GB RAM and gets killed. Maybe a transition to a slower, but more stable state machine processing line by line as in https://gitlab.com/jorispio/ccsds2czml. Although the parsing algorithm there is also behaving poorly with multiple segments.

I've tried to use google/re2 python wrappers for a more efficient processing of the file, but still fails. I'll take a look on rewriting the parser.

Edit: only the match() call seems to create issues, find_all() and running the match for the header section separately works fine.

I prepared this modification in order to handle the reading of an OEM file in XML format that has a namespace in it. The modification will remove from the tag the namespace, it is transparent for XML files without namespace.

This branch implements a test demonstrating compare between two non-identical ephemerides with reference results taken from an independent software package.

Add EphemerisSegment.__sub__ method to support EphemerisSegment comparisons. Subtraction will return a SegmentCompare instance with steps method for sampling the compare segment.

Add State.__sub__ method to support State comparisons. Subtraction will return a StateCompare instance with range, range_rate, position, and velocity attributes.

This change updates the package setup.py to better communicate the details and dependencies of the package. The requirements.txt file has also been updated to remove an unused dependency.

The current setup.py is configured for CI/CD use only and does not properly support local builds. Find a solution that works for both.

Issue noted in PR #69