Bugfix/358 datetime truncation

[ocsmit]

Github Issue: #358

Description

See #358 for detailed explanation. TLDR is misalignment between child nodes and root node for OCO3_L2_Lite_SIF temporal subset was due to inconsistent precision in the parsing of time.

Overview of work done

Updates _convert_time_from_description to use ns precision, and time_encoding to only specify dtype for time data if units is also present in the original data.

Overview of verification done

See #358

Overview of integration done

PR checklist:

• Linted
• Updated unit tests
• Updated changelog
• Integration testing

[Copilot]

Pull request overview

This PR fixes a datetime truncation bug (#358) where temporal subsetting of OCO3_L2_Lite_SIF data caused misalignment between child and root nodes due to inconsistent time precision.

Key Changes:

• Updated _convert_time_from_description to use nanosecond precision instead of second precision
• Modified time encoding logic to only specify dtype when units are also present in the original data

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
podaac/subsetter/utils/time_utils.py	Enhanced time conversion to use nanosecond precision for more accurate datetime handling
podaac/subsetter/subset.py	Added conditional check to ensure dtype is only set when units are present, preventing encoding inconsistencies
CHANGELOG.md	Documented the precision improvements and encoding condition changes

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[Copilot]

Line 359 redundantly sets 'units' even though it was already set on line 356 when the units variable is truthy. This duplicate assignment is unnecessary since units is already assigned in the preceding conditional block.

Suggested change

time_encoding[group_path][var_name]['units'] = units