hydrogeofetch

Renamed from nhdplusTools

hydrogeofetch (hydrologic geospatial fabric extraction tool chain) is the renamed successor to nhdplusTools. The package scope has grown beyond NHDPlus, and the new name reflects that broader role. All functions, signatures, and behavior carry over unchanged.

nhdplusTools will remain on CRAN as a deprecation shim forwarding calls to hydrogeofetch until October 2028, at which point it will be archived. Archived packages stay installable from the CRAN archive, so code pinned to nhdplusTools will continue to run.

hydrogeofetch: Tools for Accessing and Working with the NHDPlus and other US hydrographic data.

Major changes in 2.0.0

Indexing, network navigation, and network attribute functions have moved to hydroloom. hydrogeofetch is now focused on data access and NHD-specific preparation; hydroloom handles the general-purpose network analysis that was previously bundled here.

If you use any of the following, you now need library(hydroloom):

• Indexing (get_flowline_index, get_waterbody_index, disambiguate_flowline_indexes) → hydroloom::index_points_to_lines(), index_points_to_waterbodies(), disambiguate_indexes()
• Navigation (get_UT, get_DM, get_UM, get_DD, navigate_network) → hydroloom::navigate_hydro_network()
• Network attributes (get_streamorder, get_levelpaths, get_pathlength, calculate_total_drainage_area, etc.) → hydroloom’s add_streamorder(), add_levelpaths(), add_pathlength(), accumulate_downstream()

The typical workflow is now: use hydrogeofetch to fetch and prepare NHD data, then hand off to hydroloom for indexing, navigation, and network analysis. See vignette("migrating_from_nhdplusTools") for a complete mapping of old to new function names.

Recommended Citation:

  Blodgett, D. 2026, hydrogeofetch: Hydrologic Geospatial
  Fabric Extraction Tool Chain, https://doi.org/10.5066/P13UWPUR

Installation:

install.packages("nhdplusTools")

For the latest development:

install.packages("remotes")
remotes::install_github("DOI-USGS/nhdplusTools")

Resources

For data discovery and access in a U.S. context, start with the Getting Started page.

Detailed documentation of all the package functions can be found at the Reference page.

Data:

hydrogeofetch provides easy access to data associated with the U.S. National Hydrography Dataset. Network analysis and spatial indexing live in hydroloom.

Package Vision

The hydrogeofetch package provides tools to discover, download, subset, and prepare U.S. NHDPlus data. Network analysis (navigation, indexing, attribute generation) belongs in hydroloom.

General, globally applicable functionality has been moved to hydroloom.

hydrogeofetch implements a data model consistent with both the NHDPlus dataset and the HY_Features data model. The package aims to provide a set of tools that can be used to build workflows using hydrographic data.

This vision is intended as a guide to contributors – conveying what kinds of contributions are of interest to the package’s long term vision. It is a reflection of the current thinking and is open to discussion and modification.

Functional Vision

The following describe a vision for the functionality that should be included in the package in the long run.

Subsetting

The NHDPlus is a very large dataset both spatially and in terms of the number of attributes it contains. Subsetting utilities will provide network location discovery, network navigation, and data export utilities to generate spatial and attribute subsets of the NHDPlus dataset.

Indexing

Indexing data to the hydrographic network (linear referencing and catchment indexing) is handled by hydroloom. hydrogeofetch provides the data access needed to set up indexing workflows.

Data Model

hydrogeofetch works with a range of U.S. hydrographic data, with NHDPlus as its primary dataset, so the NHDPlus data model largely governs the data model the package is designed to work with. That said, much of the package functionality also uses concepts from the HY_Features standard, and support for additional datasets, such as 3DHP, continues to grow.

Note: The HY_Features standard is based on the notion that a “catchment” is a holistic feature that can be “realized” (some might say modeled) in a number of ways. In other words, a catchment can only be characterized fully through a collection of different conceptual representations. In NHDPlus, the “catchment” feature is the polygon feature that describes the drainage divide around the hydrologic unit that contributes surface flow to a given NHD flowline. While this may seem like a significant difference, in reality, the NHDPlus COMID identifier lends itself very well to the HY_Features catchment concept. The COMID is used as an identifier for the catchment polygon, the flowline that connects the catchment inlet and outlet, and value added attributes that describe characteristics of the catchment’s interior. In this way, the COMID identifier is actually an identifier for a collection of data that together fully describe an NHDPlus catchment. See the NHDPlus mapping to HY_Features in the HY_Features specification.

Below is a description of the scope of data used by the hydrogeofetch package. While other data and attributes may come into scope, it should only be done as a naive pass-through, as in data subsetting, or with considerable deliberation.

Flowlines and Waterbodies

Flowline geometry is a mix of 1-d streams and 1-d “artificial paths”. In order to complete the set of features meant to represent water, we need to include waterbody polygons.

Catchment Polygons

Catchment polygons are the result of a complete elevation derived hydrography process with hydro-enforcement applied with both Watershed Boundary Dataset Hydrologic Units and NHD reaches.

Network Attributes

The NHDPlus includes numerous attributes that are built using the network and allow a wide array of capabilities that would require excessive iteration or sophisticated and complex graph-oriented data structures and algorithms.

Architecture

The NHDPlus is a very large dataset. The architecture of this package as it relates to handling data and what dependencies are used will be very important.

Web vs Local Data

hydrogeofetch offers a mix of web service and local data functionality. Web services have generally been avoided for large processes. However, applications that would require loading significant amounts of data to perform something that can be accomplished with a web service very quickly are supported. Systems like the Network Linked Data Index are used for data discovery.

NHDPlus Version

Initial package development focused on the National Seamless NHDPlus database. NHDPlus High Resolution is also supported.

Build and release:

Development happens on GitHub (doi-usgs/nhdplusTools). Official builds and release candidates are produced on code.usgs.gov (code.usgs.gov/water/nhdplusTools) using GitLab CI.

Vignettes use the BUILD_VIGNETTES environment variable to control code evaluation. Set BUILD_VIGNETTES=TRUE in a local .Renviron to build vignettes with live code. Without it, vignettes render with static output only. An additional BUILD_VIGNETTES_CRAN=TRUE variable controls image size in the drainage area vignette.

Local development does not require building the source package. Use devtools::test(), devtools::check(), and devtools::document() directly.

Release candidates are built on code.usgs.gov. Push a branch named rc/<version> (e.g. rc/2.0.0) to trigger the GitLab CI pipeline, which runs three stages:

1. check – lightweight structural check (no tests, no examples, no vignettes). Gates the rest of the pipeline.
2. build – R CMD build . to produce the source tarball. Uploads the tarball to the GitLab generic package registry.
3. verify – R CMD check --as-cran on the built tarball.

Once the pipeline passes, download the tarball from the package registry and submit it to CRAN. The tarball that CRAN receives is the exact artifact that passed --as-cran in CI.

Release checklist:

• All checks pass and code coverage is adequate
• NEWS.md is up to date
• Disclaimer is in released form
• Version updated in inst/CITATION and code.json
• Push rc/<version> branch to code.usgs.gov and confirm pipeline passes
• Download tarball from GitLab package registry and submit to CRAN
• After CRAN acceptance:
  • Ensure pkgdown is up to date
  • Commit, push, and PR/MR changes
  • Create release page and tag
  • Attach CRAN tar.gz to release page
  • Update DOI to point to release page
  • Switch README disclaimer back to “dev” mode
  • Bump version in DESCRIPTION

Contributing:

First, thanks for considering a contribution! I hope to make this package a community created resource for us all to gain from and won’t be able to do that without your help!

1. Contributions should be thoroughly tested with testthat.
   
2. Code style should attempt to follow the tidyverse style guide.
   
3. Please attempt to describe what you want to do prior to contributing by submitting an issue.
   
4. Please follow the typical github fork - pull-request workflow.
   
5. Make sure you use roxygen and run Check before contributing. More on this front as the package matures.

Other notes: - consider running lintr prior to contributing. - consider running goodpractice::gp() on the package before contributing. - consider running devtools::spell_check() if you wrote documentation. - this package uses pkgdown. Running pkgdown::build_site() will refresh it.

Disclaimer

This software is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The software has not received final approval by the U.S. Geological Survey (USGS). No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. The software is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the software.