Thr3mi L1C reader

[pepephillips]

• Closes #xxxx
• Tests added
• Fully documented

[pepephillips]

i just looked at the commits and there is an old MAP L1C reader commit in there. The MAP L1C readers were since removed and obviously not part of the final commit, only the new 3MI readers are there.

[codecov]

Codecov Report

Attention: Patch coverage is 95.89744% with 8 lines in your changes missing coverage. Please review.

Project coverage is 96.23%. Comparing base (78e88c4) to head (88f6e83).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
satpy/readers/thr3mi_l1c_nc.py	92.50%	6 Missing ⚠️
satpy/tests/reader_tests/test_thr3mi_l1c_nc.py	98.26%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2908      +/-   ##
==========================================
- Coverage   96.23%   96.23%   -0.01%     
==========================================
  Files         398      400       +2     
  Lines       57325    57520     +195     
==========================================
+ Hits        55168    55355     +187     
- Misses       2157     2165       +8     

Flag	Coverage Δ
behaviourtests	3.86% <0.00%> (-0.02%)	⬇️
unittests	96.32% <95.89%> (-0.01%)	⬇️

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[ameraner]

pre-commit.ci autofix

[coveralls]

Pull Request Test Coverage Report for Build 14907297120

Details

• 189 of 197 (95.94%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.002%) to 96.338%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
satpy/tests/reader_tests/test_thr3mi_l1c_nc.py	114	116	98.28%
satpy/readers/thr3mi_l1c_nc.py	75	81	92.59%

Totals
Change from base Build 14862404225:	-0.002%
Covered Lines:	55617
Relevant Lines:	57731

---

💛 - Coveralls

[pepephillips]

@mraspaud, this is a very basic 3mi L1C reader for the native 3mi normalised reflectances in the 1D data format. As a result, scene.show() will not work as the data is still 1D (but I can hopefully update that later). However, once resampled, you can plot the projected data ok using show(). I suspect my coding is too basic and I hope someone can improve on it downstream.... I hope to include conversion to reflectance/radiance and colour composites (including polarised composites) too.