SSN2

Spec sheet

Purpose

SSN2 is an R package for spatial statistical modeling and prediction on stream networks, including models based on in-stream distance.Read 5 Oct 2026 · usepa.github.io

Support

Users can get help by opening a GitHub issue, emailing the SSN support team, or posting on Stack Overflow or Cross Validated.Read 5 Oct 2026 · usepa.github.io

License

The project is licensed under the GNU General Public License, GPL-3.Read 5 Oct 2026 · usepa.github.io

Data handling

SSN2 imports stream edges, observed sites, and optional prediction sites from a non-proprietary .ssn folder.Read 5 Oct 2026 · usepa.github.io

Dependencies

SSN2 imports sf for spatial data handling and spmodel for modeling functions, among other R packages.Read 5 Oct 2026 · usepa.github.io

Diagnostics

Available functions include model augmentation, influence diagnostics, leave-one-out cross-validation, and fitted-model diagnostic plots.Read 5 Oct 2026 · usepa.github.io

Installation

The site documents installation from CRAN and GitHub.Read 5 Oct 2026 · usepa.github.io

Intended use

The package is designed for users fitting spatial stream network models to stream data, such as modeling stream phenomena and predicting values across a network.Read 5 Oct 2026 · usepa.github.io

Mapping

The package includes mapping and other graphical functions, and its introduction uses ggplot2 and sf for visualizations.Read 5 Oct 2026 · usepa.github.io

Model types

It supports linear and generalized linear spatial stream network models.Read 5 Oct 2026 · usepa.github.io

Modeling

It fits spatial linear models, including explanatory variables, using restricted or unrestricted maximum likelihood.Read 5 Oct 2026 · usepa.github.io

Predictions

The package fits and summarizes spatial stream network models and predicts at unobserved locations (Kriging).Read 5 Oct 2026 · usepa.github.io

Preprocessing

The documentation recommends the SSNbler R package to prepare input data for SSN2.Read 5 Oct 2026 · usepa.github.io

Spatial components

Its models can include tail-up, tail-down, Euclidean, and spatially independent nugget error components.Read 5 Oct 2026 · usepa.github.io

Where Specifiction places it

• GIS Software#43 of 646.1