mlt 0.1.31

CLI Tool

The mlt binary provides several commands for working with MLT files:

Commands

• dump - Parse an MLT file and dump raw layer data without decoding
• decode - Parse an MLT file, decode all layers, and dump the result (supports text and GeoJSON output)
• hexdump - Annotated byte/bit-level hexdump of an MLT file's metadata and stream payloads
• convert - Convert MVT or MLT tile files and MVT .mbtiles/.pmtiles archives to MLT
• ui - Interactive terminal visualizer for MLT files

Format conversion

Convert an MVT archive or files to MLT:

mlt convert input.mvt.pmtiles output.mlt.pmtiles

The conversion summary reports unique, decompressed tile payloads as such:

input.mvt.pmtiles -> output.mlt.pmtiles (pmtiles):
  converted 5 tiles (5 unique encoded, 0 cache hits) in 740.9ms
  size raw/archive: MVT(gzip) 813.7kB/459.8kB -> MLT(gzip) 460.3kB/357.0kB

Partial conversion

Pass --bbox min_lon,min_lat,max_lon,max_lat to convert one region of an archive, the same way martin-cp limits what it copies:

mlt convert planet.mvt.pmtiles berlin.mlt.pmtiles --bbox 13.0,52.3,13.8,52.7

Every tile overlapping the bounds is converted, at every zoom level, and the output's bounds and center metadata shrink to the region. Repeat --bbox to keep several regions. It needs an .mbtiles or .pmtiles input, the only ones that record where each tile is.

Visualizer

The visualizer command provides an interactive terminal-based UI for exploring MLT files:

# Visualize a single MLT file
cargo run -- ui path/to/file.mlt

# Browse and visualize all MLT files in a directory (recursive)
cargo run -- ui path/to/directory

Directory Mode:

• Lists every .mlt, .mvt, and .pbf file under the directory; the walk and the per-file analysis run in the background, so the list fills in while you browse
• Use ↑/↓ to navigate the file list; the preview, filter, and info panels follow the selection
• Click a column header to sort once the scan is done; click the filter checkboxes to narrow the list
• Press Enter to open and visualize a file
• Press Esc to go back to file list
• Press q to quit

Features:

• Tree View Panel (left): Browse layers and features in a hierarchical tree
  • "All" - every layer, with layer and feature counts and the tile's geometry types
  • Individual layers - the layer's features, with each property's value types and the layer's geometry types
  • Individual features - the feature's properties and geometry statistics
  • Every panel scrolls and shows a scrollbar when its content does not fit
  • The tree also scrolls sideways with </>, Shift+Left/Shift+Right, or a sideways mouse scroll
  • Hovered rows are highlighted with underlined green text
• Map Panel (right): Visual representation of the geometries
  • Shows the extent boundary as a thin gray rectangle
  • Draws the selected level in color and the rest in gray as context
  • Tessellation edges stored in the tile are drawn in dark gray inside the selected polygon, or inside a hovered one in a layer
  • Color coding by geometry type:
    • Points: Magenta (multipoint: light magenta)
    • LineStrings: Cyan (multi-linestring: light cyan)
    • Polygons: Blue/Red based on winding order (multi-polygon: same)
  • Polygon winding order visualization:
    • Blue: Counter-clockwise rings (typically outer rings)
    • Red: Clockwise rings (typically holes)
  • Selected features: Yellow
  • Hovered features: White
  • Automatically adjusts bounds to fit all visible geometries
• Mouse Interaction:
  • Hovering the map targets one level below the selection, so a layer under All, a feature under a layer, a part under a feature
  • The hovered row is underlined and the info panels describe it
  • Clicking the map selects the hovered item
• Keyboard Navigation:
  • ↑/k - Move selection up
  • ↓/j - Move selection down
  • Enter - In layer overview mode, switch to detail mode; In file browser, open selected file
  • Esc - Go back (detail -> overview -> file list) or quit if at top level
  • q - Quit the visualizer