partpost

partpost is a specialized CLI tool designed to process Delft3D FM Particle Tracking output NetCDF files. It allows users to export particle track data to various spatial and tabular formats.

Supported Formats

• Spatial: ESRI Shapefile (.shp), GPKG (.gpkg), GeoJSON (.json, .geojson), GeoJSONSeq (.geojsonl), SQLite (.sqlite), GML (.gml), KML (.kml)
• Tabular: CSV (.csv), Excel (.xlsx)

Installation

You can install partpost using Conda.

Option 1: Create a new environment

This is the recommended approach to avoid conflicts.

1. Ensure you have conda installed (e.g., Anaconda or Miniconda).

2. Navigate to the directory containing environment.yml.

3. Run the following command:

   conda env create -f environment.yml

4. Activate the environment:

   conda activate partpost

Option 2: Install into an existing environment

If you already have a working environment and want to add partpost to it:

1. Activate your environment:

   conda activate my_env

2. Install the required dependencies (if not already present):

   conda install -c conda-forge netcdf4 xarray dask bottleneck geopandas openpyxl

3. Install the package in editable mode:

   pip install -e .

Usage

The tool runs via the command line using a JSON configuration file.

partpost config.json

Configuration File (config.json)

The configuration file can contain a single task object, or a list of task objects.

Example config.json:

[
  {
    "input_nc": "D:/model_output/marine-refuse_trk.nc",
    "output_path": "D:/gis_data/particles_hourly.shp",
    "mode": "point",
    "downscale_hour": 1.0
  },
  {
    "input_nc": "D:/model_output/marine-refuse_trk.nc",
    "output_path": "D:/gis_data/tracks_summary.gpkg",
    "mode": "line",
    "downscale_hour": 2.0
  },
  {
    "input_nc": "D:/model_output/marine-refuse_trk.nc",
    "output_path": "D:/gis_data/particles_raw.csv",
    "mode": "point",
    "downscale_hour": 0.5
  }
]

Parameters

Parameter	Type	Description
input_nc	string	Absolute path to the input NetCDF file.
output_path	string	Absolute path to the output file. The format is determined by the file extension (e.g., .shp, .gpkg, .csv).
mode	string	point for instantaneous locations, line for particle tracks.
downscale_hour	float	Time sampling interval in hours. Default is 1.0. Use 0.5 for 30 minutes.

Notes on Shapefiles

When exporting to ESRI Shapefile format, partpost explicitly converts all datetime fields to strings. This prevents compatibility issues with GIS software that may not correctly interpret Shapefile date/time fields.