document(README): add goals and main features

README.md

@@ -1,20 +1,34 @@
-# ecosystemom
-Ecosystem operating model. Generates data sets from ecosystem model scenarios for stock assessment models.
-
-## Installing ecosystemom
-
-Install the most recent version of FIMSdiags using the following code:
-
-```r
-install.packages("remotes")
-remotes::install_github("NOAA-FIMS/ecosystemom")
-```
-or using {pak}
-
-```r
-pak::pak("NOAA-FIMS/ecosystemom")
-```
-
-## Pkgdown site
-
+# ecosystemom
+Ecosystem operating model. Generates data sets from ecosystem model scenarios for stock assessment models.
+
+## Installing ecosystemom
+
+Install the most recent version of FIMSdiags using the following code:
+
+```r
+install.packages("remotes")
+remotes::install_github("NOAA-FIMS/ecosystemom")
+```
+or using {pak}
+
+```r
+pak::pak("NOAA-FIMS/ecosystemom")
+```
+
+## Why are we building {ecosysteom}?
+- Connect ecosystem model outputs to stock assessment simulation testing through a flexible operating model framework.
+- Support evaluation of FIMS and other assessment methods under realistic ecosystem dynamics.
+- Enable research on ecosystem-informed stock assessment approaches.
+- Foster collaboration between ecosystem modelers and stock assessment scientists.
+
+## Features
+The package includes functions below:
+
+- `load_model()` — import and standardize output from ecosystem operating models (OM). For example, this function can be used to read and standardize Ecopath with Ecosim (EwE) Ecosim outputs for downstream analyses within {ecosystemom}.
+- `get_truth()` — extract “true” population quantities from the OM, including annual or monthly biomass trajectories and biomass-at-age.
+- `sample_*()` — generate sampled observations from OM outputs for use in estimation models such as the Fisheries Integrated Modeling System (FIMS).
+- `create_dsem_inputs()` — prepare environmental covariates or diet composition data from the OM to support candidate model specifications for dynamic structural equation models (DSEMs) and related ecosystem-informed analyses.
+
+## Pkgdown site
+
 The pkgdown site is temporarily being built from the `add-a-demo` branch and is currently under active development.