## 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, or tile a `GeoJSON` file, including 3D positions, into MLT files
* **`ui`** - Interactive terminal visualizer for MLT files
### Format conversion
Convert an MVT archive or files to MLT:
```bash
mlt convert input.mvt.pmtiles output.mlt.pmtiles
```
The conversion summary reports unique, decompressed tile payloads as such:
```text
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:
```bash
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.
### Tiling GeoJSON
Give `convert` a WGS84 `GeoJSON` `FeatureCollection` to tile it into a `z/x/y.mlt` directory
as a single layer named after the file. `--max-zoom` is required, and `--min-zoom` and
`--layer` are optional; the encoder options above apply as to any other input. This writes
the v2 format, so it needs a binary built with `--features unstable-v2`:
```bash
mlt convert buildings.geojson tiles --max-zoom 14
```
Positions with an altitude (`[lon, lat, alt]`) become z coordinates on a `--z-step` grid,
a power of ten in metres from `-3` (1 mm) to `4` (10 km):
```bash
mlt convert power_lines.geojson tiles --max-zoom 14 --z-step -1
```
### Visualizer
The visualizer command provides an interactive terminal-based UI for exploring MLT files:
```bash
# 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