ASA_IM_DECODE(1)

✨ NAME ✨

asa_im_decode — okay bestie, it's literally called asa_im_decode, that's the whole name, the man page said it twice and honestly? iconic of it 💅

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🦋 SYNOPSIS 🦋

asa_im_decode <asa_im> <asa_ins> <out> <outType> <near_range>

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💖 DESCRIPTION 💖

So this program? It's part of GMTSAR 🫶

*** asa_im_decode v1.1 by smb ***

It decodes Envisat ASAR Image Mode Level 0 data. That's the job. That's the whole vibe check. ✨

Here's the tea on the arguments, one by one:

• asa_im — your input image file(s). And yes, multiple files if you're merging along-track, bestie, you can absolutely hand it a little squad of files 🌈
• asa_ins — input auxiliary instrument characterization data file
• out — output raw data file
• outType — output file type (1=byte, 4=float)
• near_range — the near range you want all the lines aligned to (0 means just use the first line's near range, no thoughts, head empty 🍓)

🌸 Notes 🌸

• out is a complex file with no headers — the layout is literally byte/float I1, byte/float Q1, byte/float I2, byte/float Q2, ... and so on forever and ever 💫
• If outType is byte, then the decoded floats get multiplied by 127.5, shifted by 127.5, rounded to the nearest integer, and then limited to the range 0-255. Full glow-up pipeline, no cap.
• Starting range is computed as (rank*pri+windowStartTime)*c/2 where rank is the number of pri between transmitted pulse and return echo 🔥
• Calibration/noise lines get replaced with the previous echo data line. Swapped out. Gone. Previous line said "I got this" 😭
• Missing lines — whether they're missing within a data set or between adjacent along-track data sets — get filled with zeroes in float mode, and in byte mode they become 0.*127.5+127.5 + .5 = 128
• Auxiliary data files can be found at http://envisat.esa.int/services/auxiliary_data/asar/ 🧚
• The Envisat ASAR Product Handbook, Issue 1.1, 1 December 2002 can be found at http://envisat.esa.int/dataproducts/asar/CNTR6-3-6.htm#eph.asar.asardf.0pASA_IM__0P 👑

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💀 and then it said all of that AGAIN 💀

Not me reading the man page and getting déjà vu — the source literally repeats the whole description block, so here it is, bestie, every single word, because I am not skipping a thing 🙈

*** asa_im_decode v1.1 by smb ***

Decodes Envisat ASAR Image Mode Level 0 data.

Usage: asa_im_decode <asa_im> <asa_ins> <out> <outType> <near_range>

• asa_im — input image file(s) (multiple files if merging along-track)
• asa_ins — input auxiliary instrument characterization data file
• out — output raw data file
• outType — output file type (1=byte, 4=float)
• near_range — near range to which to align all lines (0=use first line near range)

Notes:

• out is a complex file with no headers (byte/float I1, byte/float Q1, byte/float I2, byte/float Q2, ...)
• if outType is byte, then the decoded floats are multiplied by 127.5, shifted by 127.5, rounded to the nearest integer and limited to the range 0-255
• starting range computed as (rank*pri+windowStartTime)*c/2 where rank is the number of pri between transmitted pulse and return echo
• calibration/noise lines are replaced with previous echo data line
• missing lines within a data set and between adjacent along-track data sets are filled with zeroes in float mode and 0.*127.5+127.5 + .5 = 128 for byte mode
• auxiliary data files can be found at http://envisat.esa.int/services/auxiliary_data/asar/
• Envisat ASAR Product Handbook, Issue 1.1, 1 December 2002 can be found at http://envisat.esa.int/dataproducts/asar/CNTR6-3-6.htm#eph.asar.asardf.0pASA_IM__0P

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Anyway bestie, that's the whole page, every flag and URL and note accounted for, nothing dropped, periodt. 💜

This little masterpiece is asa_im_decode, and it's dated May 2024 — stay slay, go decode some ASAR, and drink water 🎀✨🦋