isce-framework / isce-framework/isce3

Always round up when computing L2 products' geo grid dimensions

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Dominant language
Python
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13d 1h
Merged PRs (30d)
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Description

The output geo grid of NISAR L2 products (except for the Static Layers product) is computed by the create() function in nisar/workflows/geogrid.py.

When determining the length and width of the geo grid, this function rounds each to dimension to the nearest integer.

https://github.com/isce-framework/isce3/blob/8cc6581525e608cc95fdcd883dac87e08f83e7d0/python/packages/nisar/workflows/geogrid.py#L299-L300

https://github.com/isce-framework/isce3/blob/8cc6581525e608cc95fdcd883dac87e08f83e7d0/python/packages/nisar/workflows/geogrid.py#L17-L25

In cases where this rounds down, the resulting geo grid will not include the full extents that were requested by the user in the input runconfig. The bottom_right corner will fall outside of the geo grid extents.

In order to avoid this, we should always round up instead of rounding to the nearest integer.

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Research direction

Start in nisar/workflows/geogrid.py, reading create() and the dimension calculations around lines 299-300, along with the rounding behavior described near lines 17-25. Done means the geo-grid length and width always round upward so the requested bottom_right corner remains within the resulting extents.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
data
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
55/100

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