add vast example

topics-2024/2024-04-25-vast/index_standardization.qmd

@@ -0,0 +1,37 @@
+---
+title: "Index Standardization"
+editor: visual
+---
+
+```{r}
+# Load package
+library(VAST)
+
+# load data set
+# see `?load_example` for list of stocks with example data 
+# that are installed automatically with `FishStatsUtils`. 
+example = load_example( data_set="EBS_pollock" )
+
+# Make settings (turning off bias.correct to save time for example)
+settings = make_settings( n_x = 100, 
+  Region = example$Region, 
+  purpose = "index2", 
+  bias.correct = FALSE )
+```
+
+Run model
+
+```{r}
+fit = fit_model( settings = settings, 
+  Lat_i = example$sampling_data[,'Lat'], 
+  Lon_i = example$sampling_data[,'Lon'], 
+  t_i = example$sampling_data[,'Year'], 
+  b_i = example$sampling_data[,'Catch_KG'], 
+  a_i = example$sampling_data[,'AreaSwept_km2'] )
+```
+
+
+Plot results
+```{r}
+plot( fit )
+```