NCFTOOLS

A collection of Python tools for working with NetCDF files.

Installation

pip install -e .

Features

• meshinfo: Display mesh information from FlowFM NetCDF files (node/face/edge counts, element types, spatial extent)
• nc2shp: Convert a UGRID-compliant NetCDF mesh file to ESRI Shapefiles
• transzone1: Build a transition zone from triangle mesh faces and select all intersecting faces
• transzone2: Extract the core transition zone — faces fully within the shrunk zone
• setncrain: Point a D-Flow FM model (.ext / .mdu) at a NetCDF rainfall forcing file
• rnxml: Rename dimr.xml to dimr_config.xml

Usage

Check version

ncftools --version

List all available commands

ncftools-info

meshinfo

Display mesh information from a FlowFM NetCDF file.

meshinfo -i FlowFM_net.nc
meshinfo -h

nc2shp

Convert a NetCDF mesh file to ESRI Shapefiles. Outputs {stem}_faces.shp in the output directory. Pass -d/--dissolve to additionally write {stem}_dissolved.shp, a single polygon dissolved from all mesh faces (slower on large meshes).

nc2shp -i FlowFM_net.nc
nc2shp -i mesh.nc -d
nc2shp -i mesh.nc -o output --crs EPSG:4326
nc2shp -i mesh.nc -q

transzone1

Buffer triangle mesh faces by +1 m to form a transition zone, then select all faces that intersect it. Outputs trans_zone.shp and trans_zone_extend.shp.

Triangles are identified from the type attribute column when present; otherwise they are detected automatically by vertex count (closed rings with 3 unique vertices).

transzone1 -i SHP_NC/FlowFM_net_faces.shp
transzone1 -i SHP_NC/FlowFM_net_faces.shp -o SHP_TRANS
transzone1 -i SHP_NC/FlowFM_net_faces.shp -q

transzone2

Shrink trans_zone_extend.shp (output of transzone1) by −1 m and select faces fully within the core zone. Outputs trans_zone_core.shp.

transzone2 -i SHP_NC/FlowFM_net_faces.shp -z SHP_TRANS/trans_zone_extend.shp
transzone2 -i SHP_NC/FlowFM_net_faces.shp -z SHP_TRANS/trans_zone_extend.shp -o SHP_TRANS
transzone2 -i SHP_NC/FlowFM_net_faces.shp -z SHP_TRANS/trans_zone_extend.shp -q

setncrain

Point a D-Flow FM model at a NetCDF rainfall forcing file.

Every [Meteo] block in the .ext file is rewritten to quantity=rainfall, forcingFile=<your .nc>, forcingFileType=netcdf. If the .ext file does not exist it is created from a built-in template and registered in the .mdu as ExtForceFileNew.

The NetCDF time axis is read and the model times in the .mdu are set to match it (expressed in the model's Tunit):

The forcingFile path is written relative to the .ext file (D-Flow FM resolves it that way); use --as-given to write it exactly as typed. .bak copies of the modified files are written unless --no-backup is given.

setncrain -i May28_Event.nc
setncrain -i data/May28_Event.nc --ext dflowfm/FM_model_bnd.ext
setncrain -i May28_Event.nc --mdu dflowfm/FM_model.mdu --no-time
setncrain -i May28_Event.nc --no-backup --as-given
setncrain -i May28_Event.nc -q

rnxml

Rename dimr.xml to dimr_config.xml, the name the DIMR runner expects. The file stays in its folder and its contents are not touched.

If dimr_config.xml already exists the rename is refused; pass --force to overwrite it (a .bak copy of the old target is kept unless --no-backup).

rnxml
rnxml -i model/dimr.xml
rnxml -i dimr.xml -o dimr_config.xml --force
rnxml -i dimr.xml -q

Python API

from ncftools import meshinfo

meshinfo.show_mesh_info("FlowFM_net.nc")