Application: `mm2txt`

Overview

mm2txt is a command-line tool that exports the layers of a MOLA metric map (*.mm) file as CSV/TXT files. It converts point cloud layers from metric map files into human-readable text format, making it easy to process and analyze point cloud data in spreadsheet applications, scripting languages, or custom data processing pipelines.

Features

Exports all or selected point cloud layers from a metric map file
Selectively exports specific fields in a custom order
Automatically detects and exports all point fields (coordinates, intensities, colors, timestamps, etc.)
Generates header row with field names for easy data parsing
Supports multiple point cloud types (CGenericPointsMap, CPointsMapXYZI, CPointsMapXYZIRT)
Space-delimited format compatible with most data analysis tools
Selective layer export for processing only the data you need

Usage

mm2txt <input.mm> [-l <layer_name>] [--export-fields <field1,field2,...>]

Arguments

input (required): Input metric map file (*.mm)
-l, --layer <name> (optional): Layer to export. If not provided, all layers will be exported. This argument can appear multiple times to export specific layers
--export-fields <field1,field2,...> (optional): Comma-separated list of fields to export in the specified order. If not provided, all available fields will be exported. Spaces around commas are allowed

Examples

Export all layers from a metric map:

mm2txt mymap.mm

Export only specific layers:

mm2txt mymap.mm -l raw -l filtered

Export a single layer:

mm2txt mymap.mm -l global

Export only specific fields in a custom order:

mm2txt mymap.mm --export-fields "x,y,z,intensity"

Export selected fields from specific layers:

mm2txt mymap.mm -l raw --export-fields "x, y, z, ring, time"

Export only 2D coordinates and intensity:

mm2txt mymap.mm --export-fields "x,y,intensity"

Output

The tool creates separate TXT files for each exported point cloud layer. Files are named using the pattern:

<input_filename>_<layer_name>.txt

For example, if your map file is mymap.mm and contains layers named “raw” and “filtered”, you’ll get:

mymap.mm_raw.txt
mymap.mm_filtered.txt

File Format

Each output file is a space-delimited text file with:

Header row: Column names for all point fields
Data rows: One row per point, with values for each field

Example output (all fields):

x y z intensity ring time
1.234 5.678 0.123 45.6 0 12345.678
2.345 6.789 0.234 67.8 1 12345.679
...

Example output (selected fields):

x y z intensity
1.234 5.678 0.123 45.6
2.345 6.789 0.234 67.8
...

Field Selection

When using the --export-fields option:

Fields must be specified as a comma-separated list
Spaces around commas are allowed (e.g., "x, y, z" or "x,y,z")
Fields will be exported in the exact order specified
All specified fields must exist in the point cloud, or an error will be raised
The tool validates field availability and reports available fields if a requested field is not found
This option is only supported for CGenericPointsMap point clouds; for legacy types (CPointsMapXYZI, CPointsMapXYZIRT), all fields are exported with a warning

Supported Point Fields

The tool automatically exports all available point attributes:

Coordinates: x, y, z (mandatory, float)
Float fields: intensity, normals, curvature, custom float attributes
Uint16 fields: ring, color channels, custom uint16 attributes
Double fields: time, timestamps, custom double attributes (MRPT ≥ 2.15.3)
Uint8 fields: custom uint8 attributes (MRPT ≥ 2.15.3)

The specific fields exported depend on the point cloud type in each layer. Use --export-fields to select only the fields you need.

Supported Point Cloud Types

CGenericPointsMap: Generic point clouds with custom fields (full support for --export-fields)
CPointsMapXYZI (Deprecated): Point clouds with intensity values (--export-fields not supported)
CPointsMapXYZIRT (Deprecated): Point clouds with intensity, ring, and time information (--export-fields not supported)

Application: mm2txt