SSN2

Free plan

What SSN2 is

SSN2 is a free R package for statistical modeling and prediction on stream networks. It fits spatial linear and generalized linear models, including explanatory variables, using restricted or unrestricted maximum likelihood. Models can represent tail-up, tail-down, Euclidean, and spatially independent nugget components, including relationships based on in-stream distance. The package summarizes fitted models and predicts values at unobserved locations with Kriging. Input comes from a non-proprietary .ssn folder containing stream edges, observed sites, and optionally prediction sites; documentation recommends SSNbler for preparing those files. Diagnostics include model augmentation, influence analysis, leave-one-out cross-validation, and fitted-model plots. Mapping and graphical functions are included, with ggplot2 and sf used in the introduction. Installation is documented for CRAN and GitHub. SSN2 is licensed under GPL-3 and support is available through GitHub issues, email, Stack Overflow, or Cross Validated.

Who it suits

It suits R users modeling stream phenomena or predicting values across a stream network. Users need stream-network data and may benefit from SSNbler preprocessing.

What it does well

Free GPL-3 package
Linear and generalized linear stream models
Kriging at unobserved locations
Cross-validation and influence diagnostics
CRAN and GitHub installation

What to know first

Requires .ssn folder input
Designed for desktop R workflows
Needs other R packages

Verdict

SSN2 combines stream-network spatial models, prediction, diagnostics, and mapping in a free R package. Its workflow requires correctly prepared .ssn data and supporting R dependencies.

Facts from SSN2's own pages

Data handling: SSN2 imports stream edges, observed sites, and optional prediction sites from a non-proprietary .ssn folder. · usepa.github.io, 5 Oct 2026
Dependencies: SSN2 imports sf for spatial data handling and spmodel for modeling functions, among other R packages. · usepa.github.io, 5 Oct 2026
Diagnostics: Available functions include model augmentation, influence diagnostics, leave-one-out cross-validation, and fitted-model diagnostic plots. · usepa.github.io, 5 Oct 2026
Installation: The site documents installation from CRAN and GitHub. · usepa.github.io, 5 Oct 2026
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. · usepa.github.io, 5 Oct 2026
License: The project is licensed under the GNU General Public License, GPL-3. · usepa.github.io, 5 Oct 2026
Mapping: The package includes mapping and other graphical functions, and its introduction uses ggplot2 and sf for visualizations. · usepa.github.io, 5 Oct 2026
Modeling: It fits spatial linear models, including explanatory variables, using restricted or unrestricted maximum likelihood. · usepa.github.io, 5 Oct 2026
Model types: It supports linear and generalized linear spatial stream network models. · usepa.github.io, 5 Oct 2026
Predictions: The package fits and summarizes spatial stream network models and predicts at unobserved locations (Kriging). · usepa.github.io, 5 Oct 2026
Preprocessing: The documentation recommends the SSNbler R package to prepare input data for SSN2. · usepa.github.io, 5 Oct 2026
Purpose: SSN2 is an R package for spatial statistical modeling and prediction on stream networks, including models based on in-stream distance. · usepa.github.io, 5 Oct 2026
Spatial components: Its models can include tail-up, tail-down, Euclidean, and spatially independent nugget error components. · usepa.github.io, 5 Oct 2026
Support: Users can get help by opening a GitHub issue, emailing the SSN support team, or posting on Stack Overflow or Cross Validated. · usepa.github.io, 5 Oct 2026

Where SSN2 stands on Freedom251

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