ngen-datastream automates the process of collecting and formatting input data for NextGen, orchestrating the NextGen run through NextGen In a Box (NGIAB), and handling outputs. This software allows users to run NextGen in an efficient, relatively painless, and reproducible fashion.

• Installation: Follow the step-by-step instructions in the Installation Guide to set up ngen-datastream on your system.
• Usage: Learn how to use ngen-datastream effectively by referring to the comprehensive Usage Guide.

ngen-datastream can be executed using cli args or a configuration file. Not all arguments are requried.

> cd ngen-datastream && ./scripts/stream.sh --help

Usage: ./scripts/stream.sh [options]
Either provide a datastream configuration file
  -c, --CONF_FILE           <Path to datastream configuration file> 
or run with cli args
  -s, --START_DATE          <YYYYMMDDHHMM or "DAILY"> 
  -e, --END_DATE            <YYYYMMDDHHMM> 
  -D, --DOMAIN_NAME         <Name for spatial domain> 
  -g, --GEOPACAKGE          <Path to geopackage file> 
  -G, --GEOPACKAGE_ATTR     <Path to geopackage attributes file> 
  -w, --HYDROFABRIC_WEIGHTS <Path to hydrofabric weights parquet> 
  -I, --SUBSET_ID           <Hydrofabric id to subset>  
  -i, --SUBSET_ID_TYPE      <Hydrofabric id type>  
  -v, --HYDROFABRIC_VERSION <Hydrofabric version> 
  -R, --REALIZATION         <Path to realization file> 
  -d, --DATA_DIR            <Path to write to> 
  -r, --RESOURCE_DIR        <Path to resource directory> 
  -f, --NWM_FORCINGS_DIR    <Path to nwm forcings directory> 
  -F, --NGEN_FORCINGS       <Path to ngen forcings tarball> 
  -S, --S3_MOUNT            <Path to mount s3 bucket to>  
  -o, --S3_PREFIX           <File prefix within s3 mount>
  -n, --NPROCS              <Process limit> 

This command will execute a 24 hour NextGen simulation over VPU 09 with CFE, SLOTH, PET, and NOM configuration distributed over 4 processes. See more examples.

./scripts/stream.sh \
  -s 202405200100 \
  -e 202405210000 \
  -d $(pwd)/data/datastream_test \
  -g https://lynker-spatial.s3.amazonaws.com/hydrofabric/v20.1/gpkg/nextgen_09.gpkg \
  -G https://lynker-spatial.s3.amazonaws.com/hydrofabric/v20.1/model_attributes/nextgen_09.parquet \
  -R $(pwd)/configs/ngen/realization_cfe_sloth_pet_nom.json \
  -n 4

When the datastream is executed a folder of the structure below will be constructed at DATA_DIR

DATA-PATH/
│
├── datastream-metadata/
│
├── datastream-resources/
|
├── ngen-run/

Each folder is explained below

Holds metadata about the ngen-datastream excution that allows for a relatively condensed view of how the execution was performed. Example directory:

datastream-metadata/
│
├── conf_datastream.json
│
├── conf_fp.json
|
├── conf_nwmurl.json
|
├── profile.txt
|
├── filenamelist.txt
|
├── realization.json

datastream-resources/ holds all the input data files required to perform the various computations ngen-datastream performs. This folder is not required as input, but will be a faster method for running ngen-datastream repeatedly over a given spatial or time domain.

Examples of the application of the resource directory:

1. Repeated executions. ngen-datastream will retrieve files (that are given as arguements) remotely, however this can take time depending on the networking between the data source and host. Storing these files locally in RESOURCE_DIR for repeated runs will save time and network bandwith. In addition, this saves on compute required to build input files from scratch.
2. Communicating runs. ngen-datastream versions everything in DATA_DIR, which means a single hash corresponds to a unique RESOURCE_DIR, which allows users to quickly identify potential differences between ngen-datastream input data.

The easiest way to create a reusable resource directory is to execute ngen-datastream and save DATA_DIR/datastream-resources for later use. A user defined RESOURCE_DIR may take the form below. Only one file of each type is allowed (e.g. cannot have two geopackages or two realizations). Not every file is required. ngen-datastream will generate all required files by default, but will skip those steps if corresponding files exist in the resource directory.

RESOURCE_DIR/
|
├── config/
|   │
|   ├── ngen-bmi-configs.tar.gz
|   │
|   ├── realization.json 
|   
├── datastream
|   |
|   ├── partitions.json
|   │
|   ├── weights.json
|
|── hydrofabric
|   |
|   |── nextgen_01.gpkg
|   │
|   ├── nextgen_01.parquet
|   │
|   ├── weights.parquet
|
├── nwm-forcings/
|   |
|   ├── nwm.t00z.medium_range.forcing.f001.conus
|   |
|   ├── ...
|
├── ngen-forcings/
|   |
|   ├── forcings.tar.gz
|

Running NextGen requires building a standard run directory complete with only the necessary files. The datastream constructs this automatically, but can be manually built as well. Below is an explanation of the standard. Reference for discussion of the standard here.

A NextGen run directory ngen-run is composed of three necessary subfolders config, forcings, outputs and an optional fourth subfolder metadata.

ngen-run/
│
├── config/
│
├── forcings/
|
├── metadata/
│
├── outputs/

The ngen-run directory contains the following subfolders:

• config: model configuration files and hydrofabric configuration files. A deeper explanation here
• forcings: catchment-level forcing timeseries files. These can be generated with the forcingprocessor. Forcing files contain variables like wind speed, temperature, precipitation, and solar radiation.
• metadata is an optional subfolder. This is programmatically generated and it used within to ngen. Do not edit this folder.
• outputs: This is where ngen will place the output files.

Model Configuration Example files: config.ini,realization.json The realization file serves as the primary model configuration for the ngen framework. Downloand an example realization file here. This file specifies which models/modules to run and with which parameters, run parameters like date and time, and hydrofabric specifications. If experiencing run-time errors, the realization file is the first place to check. Other files may be placed in this subdirectory that relate to internal-ngen-models/modules (config.ini). It is common to define variables like soil parameters in these files for ngen modules to use.

Hydrofabric Example files: nextgen_01.gpkg,nextgen_01.parquet NextGen requires a single geopackage file. This fle is the hydrofabric (spatial data). An example geopackage can be found here. Tools to subset a geopackage into a smaller domain can be found at Lynker's hfsubset. ngen-datastream requires a geopackage attributes file, nextgen_01.parquet, which is required for generating ngen bmi module configuration files.

ngen-datstream uses a merkel tree hashing algorithm to version each execution with merkdir. This means all input and output files in a ngen-datastream execution will be hashed in such a way that tracking minute changes among millions of files is trivial.

ngen-datastream is distributed under GNU General Public License v3.0 or later