topo_smooth v3.2.3¶

Mercurial revision 5827:6131e4c94bf4 | 2026-09-18

Description¶

topo_smooth is a tool designed to smooth bathymetry data (either globally or within a specified polygon) using median or LOESS filters. It allows for fine-tuning of depth values and scaling adjustments to refine the bathymetric surface.

Usage¶

topo_smooth [OPTIONS] -b <bathymetry_file>

Options¶

Input/Output Options¶

Option	Description
`-h`, `--help`	Display help and exit.
`-b <file>`	Required. Path to the input bathymetry file.
`-o <rootname>`	Output rootname (default: `out`).
`-f <format>`, `-oF <format>`	Output format: `grd`, `grd-float`, `nectdf`, or `xyz` (default: `grd`).

Filtering Options¶

Option	Description
`-p <file>`	Path to a closed polygon file defining the area where the filter will be applied.
`–filter=[median	loess]`
`-r <radius>`	Radius of the filter (in degrees).

Depth Adjustment Options¶

Option	Description
`-zmin <depth>`	Minimum depth for filtered bathymetry (default: `-500`).
`-zmax <depth>`	Maximum depth for filtered bathymetry (default: `0`).
`-inv`	Invert depth/altitude on the selected area. Equivalent to `-scale -1`.
`-scale <factor>`	Scale factor to apply on the selected area and smooth edges to merge with surroundings.

Note: -inv and -scale cannot be used together. The last one specified will override the previous.

Examples¶

Basic Smoothing with LOESS Filter¶

Smooth the entire bathymetry file using the default LOESS filter:

topo_smooth -b bathymetry.grd

Smooth a Specific Polygon Area¶

Apply LOESS smoothing to a specific polygon area:

topo_smooth -b bathymetry.grd -p polygon.txt -r 0.1

Smooth with Median Filter¶

Use the median filter for smoothing:

topo_smooth -b bathymetry.grd --filter=median -r 0.05

Set Depth Range for Smoothing¶

Smooth only depths between -1000 and -100 meters:

topo_smooth -b bathymetry.grd -zmin -1000 -zmax -100

Invert Depth Values¶

Invert depth/altitude values in the selected area:

topo_smooth -b bathymetry.grd -p polygon.txt -inv

Scale Depth Values¶

Apply a scale factor of 1.5 to the selected area:

topo_smooth -b bathymetry.grd -p polygon.txt -scale 1.5

Custom Output Format and Rootname¶

Save the smoothed bathymetry in xyz format with a custom rootname:

topo_smooth -b bathymetry.grd -o smoothed_bathy -f xyz

Combine Filtering and Depth Range¶

Apply a median filter with a radius of 0.2 degrees and restrict smoothing to depths between -2000 and -50:

topo_smooth -b bathymetry.grd --filter=median -r 0.2 -zmin -2000 -zmax -50

Environment Variables¶

topo_smooth does not rely on specific environment variables. However, ensure your system has sufficient memory and disk space for large bathymetry files.

Notes¶

Input File:

The -b option is mandatory to specify the input bathymetry file.

Polygon File:

The polygon file (-p) must define a closed polygon (e.g., a shapefile or ASCII file with coordinates).

Filter Selection:

The default filter is LOESS. Use --filter=median to switch to median filtering.

Depth Range:

The -zmin and -zmax options define the depth range for filtering. Values outside this range will not be smoothed.

Scaling and Inversion:

-inv and -scale are mutually exclusive. The last one specified will override the other.
-inv is equivalent to -scale -1.

Output:

If no output rootname (-o) is provided, the default is out.
Supported output formats: grd, grd-float, nectdf, xyz.

Deprecated Options:

Previously, adding a file to the command without options was interpreted as a trusted bathymetry file for outlier removal. This is no longer supported.