`prep_gmtsar`: grab `A/RLOOKS` from GMTSAR config file if available #1389

yunjunz · 2025-07-05T15:40:52Z

Description of proposed changes

utils.readfile.read_gmtsar_prm(): support reading GMTSAR config file, which may have empty key values or may not have some keys as in the PRM file
prep_gmtsar.extract_gmtsar_metadata(): support grabing A/RLOOKS from the config file if available, which is usually named as config.{SAT}.txt, where SAT can be ERS, ENVI, ALOS, ALOS_SLC, ALOS2, ALOS2_SCAN, S1_STRIP, S1_TOPS, CSK_RAW, CSK_SLC, CSG, TSX, RS2, GF3, LT1, with help from @Xiaohua-Eric-Xu.
docs/dir_structure.md: add config.tops.txt file to the example directory
docs/demo_dataset.md: update the zenodo link for the new example dataset (with the config.tops.txt file added)

Reminders

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Make sure that your code follows our style. Use the other functions/files as a basis.
If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.

Summary by Sourcery

Add robust GMTSAR config file support for metadata extraction, improve parameter parsing resilience, adjust radar look direction handling, and refresh relevant documentation examples.

New Features:

Support reading GMTSAR configuration files in read_gmtsar_prm to handle empty or missing keys
Extract A/RLOOKS and RLOOKS from GMTSAR config files in prep_gmtsar.extract_gmtsar_metadata

Enhancements:

Ignore lines with empty keys when parsing GMTSAR parameter files
Conditionally compute CENTER_LINE_UTC and PLATFORM only if related keys are present
Assume right-looking radar for azimuth angle in asc_desc2horz_vert

Documentation:

Add config.tops.txt to example directory structure documentation
Update demo dataset Zenodo link and include config.tops.txt in docs

+ utils.readfile.read_gmtsar_prm(): support reading GMTSAR config file, which may have empty key values or may not have some keys as in the PRM file + prep_gmtsar.extract_gmtsar_metadata(): support grabing A/RLOOKS from the config.tops.txt file if available + docs/dir_structure.md: add config.tops.txt file to the example directory + docs/demo_dataset.md: update the zenodo link for the new example dataset (with the config.tops.txt file added)

sourcery-ai · 2025-07-05T15:40:57Z

Reviewer's Guide

This PR enhances GMTSAR parameter handling by improving the parser to skip empty entries and conditionally map attributes, augments metadata extraction to pull processing looks from an external config file (with template fallback) while updating pixel sizing, adds targeted debug logging throughout prep_gmtsar, tweaks the heading-to-azimuth conversion for right-looking geometry, and brings documentation up to date with the new config file and demo dataset link.

Sequence diagram for extracting A/RLOOKS from config or template in GMTSAR metadata extraction

sequenceDiagram
    participant User
    participant prep_gmtsar.extract_gmtsar_metadata
    participant readfile.read_gmtsar_prm
    participant readfile.read_template
    participant config_file
    participant template_file

    User->>prep_gmtsar.extract_gmtsar_metadata: Call with meta_file, unw_file, template_file
    prep_gmtsar.extract_gmtsar_metadata->>readfile.read_gmtsar_prm: Read meta_file
    readfile.read_gmtsar_prm-->>prep_gmtsar.extract_gmtsar_metadata: Return meta dict
    prep_gmtsar.extract_gmtsar_metadata->>config_file: Check if config.tops.txt exists
    alt config file exists
        prep_gmtsar.extract_gmtsar_metadata->>readfile.read_gmtsar_prm: Read config_file
        readfile.read_gmtsar_prm-->>prep_gmtsar.extract_gmtsar_metadata: Return config dict
        prep_gmtsar.extract_gmtsar_metadata->>prep_gmtsar.extract_gmtsar_metadata: Calculate ALOOKS/RLOOKS from config
    else config file missing
        prep_gmtsar.extract_gmtsar_metadata->>readfile.read_template: Read template_file
        readfile.read_template-->>prep_gmtsar.extract_gmtsar_metadata: Return template dict
        prep_gmtsar.extract_gmtsar_metadata->>prep_gmtsar.extract_gmtsar_metadata: Get ALOOKS/RLOOKS from template
    end
    prep_gmtsar.extract_gmtsar_metadata->>prep_gmtsar.extract_gmtsar_metadata: Update pixel sizes
    prep_gmtsar.extract_gmtsar_metadata-->>User: Return updated metadata

Class diagram for updated GMTSAR parameter reading and metadata extraction

classDiagram
    class readfile {
        +read_gmtsar_prm(fname, delimiter='=')
        +read_template(template_file)
    }
    class prep_gmtsar {
        +extract_gmtsar_metadata(meta_file, unw_file, template_file, ...)
    }
    readfile <.. prep_gmtsar : uses
    class read_gmtsar_prm {
        +skips empty key values
        +conditionally maps SC_clock_start/stop and SC_identity
    }
    readfile ..> read_gmtsar_prm : calls
    class extract_gmtsar_metadata {
        +reads ALOOKS/RLOOKS from config or template
        +updates AZIMUTH/RANGE_PIXEL_SIZE
    }
    prep_gmtsar ..> extract_gmtsar_metadata : main logic

File-Level Changes

Change	Details	Files
Enhanced GMTSAR parameter file parsing to handle missing or empty entries and conditionally map attributes	Ignore lines with empty keys in read_gmtsar_prm Only compute CENTER_LINE_UTC if SC_clock_start/stop exist Only map PLATFORM when SC_identity is present	`src/mintpy/utils/readfile.py`
Extended extract_gmtsar_metadata to read A/RLOOKS from GMTSAR config file with fallback to template	Detect and read config.tops.txt for filter_wavelength Compute ALOOKS/RLOOKS from filter_wavelength and pixel sizes Fallback to template values or raise error if missing Update AZIMUTH/RANGE_PIXEL_SIZE by multiplies of A/RLOOKS	`src/mintpy/prep_gmtsar.py`
Added informative debug prints in prep_gmtsar metadata extraction	Log when grabbing LAT/LON corner refs Log when reading SLANT_RANGE_DISTANCE and INCIDENCE_ANGLE Log metadata sources for A/RLOOKS and HEADING Log coordinate step grabs from unw_file	`src/mintpy/prep_gmtsar.py`
Adjusted azimuth angle computation to assume right-looking geometry	Pass look_direction='right' to heading2azimuth_angle Clarify log output to note right-looking radar	`src/mintpy/asc_desc2horz_vert.py`
Updated documentation for GMTSAR config integration and dataset references	Add config.tops.txt to example directory structure Refresh demo_dataset.md to point to new Zenodo link	`docs/dir_structure.md` `docs/demo_dataset.md`

Possibly linked issues

Updates for version 1.1 #1: PR modifies prep_gmtsar metadata reading code, related to the issue's file handling error in the same code area.

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sourcery-ai

Hey @yunjunz - I've reviewed your changes and they look great!

Prompt for AI Agents

Please address the comments from this code review:
## Individual Comments

### Comment 1
<location> `src/mintpy/prep_gmtsar.py:93` </location>
<code_context>
         return prm_dict

     # read corners lat/lon info
+    print(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}')
     ds = gdal.Open(geo_file, gdal.GA_ReadOnly)
     transform = ds.GetGeoTransform()
</code_context>

<issue_to_address>
Consider replacing print statements with a logging framework.

A logging framework provides better control over message levels and output, reducing clutter in standard output.

Suggested implementation:

```python
        return prm_dict

    import logging
    logging.basicConfig(level=logging.INFO)
    # read corners lat/lon info
    logging.info(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}')
    ds = gdal.Open(geo_file, gdal.GA_ReadOnly)
    transform = ds.GetGeoTransform()

```

```python
    # read width from rdr_file
    logging.info(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}')
    ds = gdal.Open(geo_file, gdal.GA_ReadOnly)
    width = ds.RasterXSize

```
</issue_to_address>

### Comment 2
<location> `src/mintpy/prep_gmtsar.py:142` </location>
<code_context>
         raise ValueError(f'No radar-coord files found in {ifg_dir} with suffix: {fbases}')

     # read width from rdr_file
+    print(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}')
     ds = gdal.Open(geo_file, gdal.GA_ReadOnly)
     width = ds.RasterXSize
</code_context>

<issue_to_address>
Prefer logging over print for status messages.

Using a logging library enhances maintainability and lets users control output verbosity.

Suggested implementation:

```python
    import logging
    logging.info(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}')

```

```python
    logging.info(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}')

```

```python
    logging.info(f'extract metadata from metadata file: {meta_file}')

```

If `import logging` is already present at the top of the file, you can remove the new import statement from the first change above. 
You may also want to ensure that logging is configured somewhere in your application, e.g., with `logging.basicConfig(level=logging.INFO)`, if not already done.
</issue_to_address>

### Comment 3
<location> `src/mintpy/prep_gmtsar.py:195` </location>
<code_context>
     # 1. read *.PRM file
-    #prm_file = get_prm_files(ifg_dir)[0]
+    # prm_file = get_prm_files(ifg_dir)[0]
+    print(f'extract metadata from metadata file: {meta_file}')
     meta = readfile.read_gmtsar_prm(meta_file)
     meta['PROCESSOR'] = 'gmtsar'
</code_context>

<issue_to_address>
Replace print with logging for better output control.

Logging offers more flexibility and can be easily managed or redirected in production environments.

Suggested implementation:

```python
    # 1. read *.PRM file
    # prm_file = get_prm_files(ifg_dir)[0]
    import logging
    logging.info(f'extract metadata from metadata file: {meta_file}')
    meta = readfile.read_gmtsar_prm(meta_file)
    meta['PROCESSOR'] = 'gmtsar'

```

If the `logging` module is already imported at the top of the file, you should remove the duplicate import from this block. Also, ensure that logging is configured somewhere in your application (e.g., with `logging.basicConfig(level=logging.INFO)`), otherwise you may not see any output.
</issue_to_address>

### Comment 4
<location> `src/mintpy/prep_gmtsar.py:210` </location>
<code_context>
+        # calc a/rlooks
+        # Note from Xiaohua Xu: GMTSAR is applying Gaussian filtering, instead of multilooing,
+        # thus, the equivalent value is ~0.3 times the mainlobe response of the boxcar filtering.
+        print(f'grab A/RLOOKS from config file: {config_file}')
+        meta['ALOOKS'] = np.rint(0.3 * filter_wvl / meta['AZIMUTH_PIXEL_SIZE']).astype(int)
+        meta['RLOOKS'] = np.rint(0.3 * filter_wvl / meta['RANGE_PIXEL_SIZE']).astype(int)
+
+    else:
</code_context>

<issue_to_address>
Consider using logging instead of print for configuration status.

Using logging allows users to adjust message verbosity and output location, which is beneficial in complex workflows.

Suggested implementation:

```python
        logging.info(f'grab A/RLOOKS from config file: {config_file}')

```

```python
        logging.warning(f'No config file found in {config_file}!')

```

```python
                logging.info(f'grab {key} from template file: {template_file}')

```

```python
    import logging
    template = readfile.read_template(template_file)

```
</issue_to_address>

### Comment 5
<location> `src/mintpy/prep_gmtsar.py:215` </location>
<code_context>
+        meta['RLOOKS'] = np.rint(0.3 * filter_wvl / meta['RANGE_PIXEL_SIZE']).astype(int)
+
+    else:
+        print(f'WARNING: No config file found in {config_file}!')
+        # read from template file
+        for key in ['ALOOKS', 'RLOOKS']:
</code_context>

<issue_to_address>
Use logging.warning for warnings instead of print.

This allows warnings to be managed and filtered more effectively.

Suggested implementation:

```python
        import logging
        logging.info(f'grab A/RLOOKS from config file: {config_file}')

```

```python
        import logging
        logging.warning(f'No config file found in {config_file}!')

```

```python
                logging.info(f'grab {key} from template file: {template_file}')

```
</issue_to_address>

### Comment 6
<location> `docs/demo_dataset.md:61` </location>
<code_context>

 + Area: San Francisco Bay, California, USA
-+ Data: Sentinel-1 A/B descending track 42 during December 2014 - June 2024 (333 acquisitoins; [Zenodo](https://zenodo.org/records/12773014))
++ Data: Sentinel-1 A/B descending track 42 during December 2014 - June 2024 (333 acquisitoins; [Zenodo](https://zenodo.org/records/15814132))
 + Size: ~2.3 GB

</code_context>

<issue_to_address>
Typo: 'acquisitoins' should be 'acquisitions'.

Please update the typo to 'acquisitions'.
</issue_to_address>

<suggested_fix>
<<<<<<< SEARCH
+ Data: Sentinel-1 A/B descending track 42 during December 2014 - June 2024 (333 acquisitoins; [Zenodo](https://zenodo.org/records/15814132))
=======
+ Data: Sentinel-1 A/B descending track 42 during December 2014 - June 2024 (333 acquisitions; [Zenodo](https://zenodo.org/records/15814132))
>>>>>>> REPLACE

</suggested_fix>

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sourcery-ai · 2025-07-05T15:42:03Z

src/mintpy/prep_gmtsar.py

        return prm_dict

    # read corners lat/lon info
+    print(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}')


suggestion: Consider replacing print statements with a logging framework.

A logging framework provides better control over message levels and output, reducing clutter in standard output.

Suggested implementation:

return prm_dict import logging logging.basicConfig(level=logging.INFO) # read corners lat/lon info logging.info(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}') ds = gdal.Open(geo_file, gdal.GA_ReadOnly) transform = ds.GetGeoTransform()

# read width from rdr_file logging.info(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}') ds = gdal.Open(geo_file, gdal.GA_ReadOnly) width = ds.RasterXSize

sourcery-ai · 2025-07-05T15:42:03Z

src/mintpy/prep_gmtsar.py

        raise ValueError(f'No radar-coord files found in {ifg_dir} with suffix: {fbases}')

    # read width from rdr_file
+    print(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}')


suggestion: Prefer logging over print for status messages.

Using a logging library enhances maintainability and lets users control output verbosity.

Suggested implementation:

import logging logging.info(f'grab LAT/LON_REF1/2/3/4 from file: {geo_file}')

logging.info(f'grab SLANT_RANGE_DISTANCE, INCIDENCE_ANGLE from file: {geo_file}')

logging.info(f'extract metadata from metadata file: {meta_file}')

If import logging is already present at the top of the file, you can remove the new import statement from the first change above.
You may also want to ensure that logging is configured somewhere in your application, e.g., with logging.basicConfig(level=logging.INFO), if not already done.

sourcery-ai · 2025-07-05T15:42:04Z

src/mintpy/prep_gmtsar.py

    # 1. read *.PRM file
-    #prm_file = get_prm_files(ifg_dir)[0]
+    # prm_file = get_prm_files(ifg_dir)[0]
+    print(f'extract metadata from metadata file: {meta_file}')


suggestion: Replace print with logging for better output control.

Logging offers more flexibility and can be easily managed or redirected in production environments.

Suggested implementation:

# 1. read *.PRM file # prm_file = get_prm_files(ifg_dir)[0] import logging logging.info(f'extract metadata from metadata file: {meta_file}') meta = readfile.read_gmtsar_prm(meta_file) meta['PROCESSOR'] = 'gmtsar'

If the logging module is already imported at the top of the file, you should remove the duplicate import from this block. Also, ensure that logging is configured somewhere in your application (e.g., with logging.basicConfig(level=logging.INFO)), otherwise you may not see any output.

sourcery-ai · 2025-07-05T15:42:04Z

src/mintpy/prep_gmtsar.py

+        print(f'grab A/RLOOKS from config file: {config_file}')
+        meta['ALOOKS'] = np.rint(0.3 * filter_wvl / meta['AZIMUTH_PIXEL_SIZE']).astype(int)
+        meta['RLOOKS'] = np.rint(0.3 * filter_wvl / meta['RANGE_PIXEL_SIZE']).astype(int)


suggestion: Consider using logging instead of print for configuration status.

Using logging allows users to adjust message verbosity and output location, which is beneficial in complex workflows.

Suggested implementation:

logging.info(f'grab A/RLOOKS from config file: {config_file}')

logging.warning(f'No config file found in {config_file}!')

logging.info(f'grab {key} from template file: {template_file}')

import logging template = readfile.read_template(template_file)

sourcery-ai · 2025-07-05T15:42:04Z

src/mintpy/prep_gmtsar.py

+        meta['RLOOKS'] = np.rint(0.3 * filter_wvl / meta['RANGE_PIXEL_SIZE']).astype(int)
+
+    else:
+        print(f'WARNING: No config file found in {config_file}!')


suggestion: Use logging.warning for warnings instead of print.

This allows warnings to be managed and filtered more effectively.

Suggested implementation:

import logging logging.info(f'grab A/RLOOKS from config file: {config_file}')

import logging logging.warning(f'No config file found in {config_file}!')

logging.info(f'grab {key} from template file: {template_file}')

docs/demo_dataset.md

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

sourcery-ai bot reviewed Jul 5, 2025

View reviewed changes

yunjunz and others added 2 commits July 5, 2025 23:48

prep_gmtsar: use wirdcard for config file

f609d08

Update docs/demo_dataset.md

96f294a

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

yunjunz merged commit 3b0005e into insarlab:main Jul 5, 2025
7 checks passed

yunjunz deleted the gmtsar_config branch July 5, 2025 16:07

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`prep_gmtsar`: grab `A/RLOOKS` from GMTSAR config file if available #1389

`prep_gmtsar`: grab `A/RLOOKS` from GMTSAR config file if available #1389

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prep_gmtsar: grab A/RLOOKS from GMTSAR config file if available #1389

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Sequence diagram for extracting A/RLOOKS from config or template in GMTSAR metadata extraction

Class diagram for updated GMTSAR parameter reading and metadata extraction

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`prep_gmtsar`: grab `A/RLOOKS` from GMTSAR config file if available #1389

`prep_gmtsar`: grab `A/RLOOKS` from GMTSAR config file if available #1389

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