support --lalo-label for UTM-geocoded products in view.py

[huchangyang]

Summary

• Enable view.py --lalo-label for UTM-geocoded files (e.g. NISAR GUNW).
• Keep the image in UTM on regular matplotlib axes; only convert tick positions/labels to lat/lon (no raster reprojection).

Approach

Previously UTM + --lalo-label raised:
ValueError: --lalo-label is NOT supported for projection: UTM

Now:

1. Skip cartopy for UTM + --lalo-label
2. Plot with UTM easting/northing as before
3. Use draw_utm_lalo_label() to place ticks at UTM coords of lat/lon lines and label them as 101°W / 19°N

Test plan

• UTM file: view.py velocity.h5 velocity --lalo-label → lat/lon tick labels
• Lat/lon geo file + --lalo-label unchanged
• UTM file without --lalo-label unchanged

Summary by Sourcery

Support lat/lon tick labeling on UTM-geocoded maps without reprojecting raster data.

New Features:

• Add draw_utm_lalo_label to render latitude/longitude tick labels for UTM-geocoded products on regular matplotlib axes.

Enhancements:

• Update view.py map projection handling so --lalo-label skips Cartopy UTM projection and keeps plots in native UTM coordinates.
• Route UTM datasets with --lalo-label through the new UTM-specific labeling helper while preserving existing behavior for lat/lon and non-lalo-label cases.

[sourcery-ai]

Reviewer's Guide

Adds support for --lalo-label on UTM-geocoded products by drawing lat/lon tick labels on regular matplotlib axes without using a Cartopy UTM projection, while keeping existing behavior for lat/lon-projected data unchanged.

Flow diagram for --lalo-label handling with UTM and latlon projections

flowchart TD
    A[extent2meshgrid] --> B{inps.lalo_label}
    B -->|False| C[ax.tick_params default UTM or latlon]
    B -->|True| D{inps.coord_unit startswith meter AND UTM_ZONE in metadata}
    D -->|True| E[draw_utm_lalo_label ax metadata inps.geo_box]
    D -->|False| F[draw_lalo_label ax inps.geo_box inps.map_proj_obj]

    subgraph UTM_lalo_label_path
        E --> G[utm2latlon metadata geo_box]
        G --> H[auto_lalo_sequence lalo_box]
        H --> I[latlon2utm metadata mid_lat lons_t]
        H --> J[latlon2utm metadata lats_t mid_lon]
        I --> K[ax.set_xticks xticks]
        J --> L[ax.set_yticks yticks]
    end

Loading

File-Level Changes

Change	Details	Files
Introduce a helper to render lat/lon tick labels for UTM-geocoded data on regular matplotlib axes.	Add draw_utm_lalo_label that converts the UTM extent to a lat/lon box via utm2latlon and derives tick lat/lon sequences using auto_lalo_sequence. Compute UTM x/y tick positions for each lat/lon tick using latlon2utm at the plot-center latitude/longitude. Format tick labels as degrees with N/S/E/W suffixes and apply them via standard matplotlib tick APIs, respecting lalo_loc, lalo_offset, and font_size options.	src/mintpy/utils/map.py
Change projection selection logic so UTM + --lalo-label no longer uses Cartopy and instead stays on regular axes.	Update check_map_projection to avoid constructing a Cartopy UTM projection when lalo_label is requested, printing a message instead of raising a ValueError. Keep existing Cartopy UTM behavior when lalo_label is not requested, preserving prior projection setup for non-lalo UTM plots.	src/mintpy/view.py
Wire the new UTM lat/lon labeling behavior into view.py and plot utilities.	Update view() to call draw_utm_lalo_label when coord_unit is meters and metadata contains UTM_ZONE, falling back to draw_lalo_label otherwise. Ensure lalo-related parameters (step, loc, max_num, offset, font size, print_msg) are passed through consistently to the appropriate draw_* function. Import draw_utm_lalo_label in plot utilities so it can be used alongside existing mapping helpers.	src/mintpy/view.py src/mintpy/utils/plot.py

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[sourcery-ai]

Hey - I've left some high level feedback:

• Consider refactoring the lat/lon label formatting (degree + N/S/E/W, decimal digits logic) into a shared helper used by both draw_lalo_label and draw_utm_lalo_label to avoid duplication and keep labeling behavior consistent across projections.
• In check_map_projection, when --lalo-label is used with UTM you now leave map_proj_obj unset; double-check other code paths that assume a non-None projection and guard or document this UTM + lalo-label behavior to avoid subtle regressions.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Consider refactoring the lat/lon label formatting (degree + N/S/E/W, decimal digits logic) into a shared helper used by both `draw_lalo_label` and `draw_utm_lalo_label` to avoid duplication and keep labeling behavior consistent across projections.
- In `check_map_projection`, when `--lalo-label` is used with UTM you now leave `map_proj_obj` unset; double-check other code paths that assume a non-`None` projection and guard or document this UTM + lalo-label behavior to avoid subtle regressions.

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