# `make.entrainment`

[`make.entrainment`](#digger.make.entrainment) generates files with a uniform thickness of entrainable material. The typical usage for [`make.entrainment`](#digger.make.entrainment) differs from [`make.scoops`](#digger.make.scoops) and [`make.slabs`](#digger.make.slabs) in that the user specifies the extent of the area *not covered* by material that can be entrained rather than the area within the landslide extent. This method was developed so the same file indicating the initial landslide extent could be used for both [`make.scoops`](#digger.make.scoops) or [`make.slabs`](#digger.make.slabs) and [`make.entrainment`](#digger.make.entrainment).

1. Prepare a topography file as a geotif. If the area of interest includes submarine regions, the topography and bathymetry should be represented as a seamless surface in a single file.
2. Prepare or obtain a shapefile containing one or more polygons indicating landslide extents. Ensure that the geotif and shapefile have the same coordinate system.
3. Run [`make.entrainment`](#digger.make.entrainment) to generate input files for D-Claw. Inspect the output and adjust any input parameters as needed.
4. Using these files, set up a D-Claw simulation to run and analyze. `digger` will not do this for you.

A code snippet that uses [`make.entrainment`](#digger.make.entrainment) may be found in the file `digger/examples/pre-run/synthetic/make_entrainment_synthetic_example.py`,

```{literalinclude} ../../../../../examples/pre-run/synthetic/make_entrainment_synthetic_example.py
:language: python
```

:::{attention}
This code snippet is not fully self-sufficient. To reproduce the example, execute the code such that the relative path is correct. This may be done by executing the example script from within the directory in which it is located.
:::

After this code runs, it will produce geotif and [topotype3](https://www.clawpack.org/topo.html) files that specify the spatial extent and initial depth of erodible material (aux5).

It will also create diagnostic figures to assist the user.

```{figure} ../../../../_static/from_examples/entrainment_source.png
:alt: Example digger.make.entrainment summary figure.

An example of the diagnostic output provided by digger.make.entrainment.
```