Update docs

docs/src/plots.md

@@ -36,10 +36,16 @@ Makie.rainclouds(A)
 
 ## AlgebraOfGraphics.jl
 
-AlgebraOfGraphics.jl is a high-level plotting library built on top of Makie.jl that provides a declarative "grammar of graphics" for creating complex visualizations. It allows you to construct plots using algebraic operations like `*` and `+`, making it easy to create sophisticated graphics with minimal code.
+AlgebraOfGraphics.jl is a high-level plotting library built on top of Makie.jl that provides a declarative algebra for creating complex visualizations, similar to `ggplot2`'s "grammar of graphics" in R. It allows you to construct plots using algebraic operations like `*` and `+`, making it easy to create sophisticated graphics with minimal code.
 
 Any `DimensionalArray` is also a `Tables.jl` table, so it can be used with `AlgebraOfGraphics.jl` directly.  You can indicate columns in `mapping` with Symbols directly (like `:X` or `:Y`), **or** you can use the `Dim` type directly (like `X` or `Y`)! 
 
+!!! note
+    If your dimensional array is not named, then you can access the data as the **`:unnamed`** column.
+    Otherwise, the data is accessible by its name.
+
+Let's start with a simple example, and plot a 2-D dimarray as a scatter plot, colored by its value.
+
 ```@example Makie
 using DimensionalData, AlgebraOfGraphics, CairoMakie
 CairoMakie.activate!(type = :svg) # hide
@@ -49,8 +55,28 @@ A = DimArray(rand(10, 10), (X(1:10), Y(1:10)), name = :data)
 data(A) * mapping(X, Y; color = :data) * visual(Scatter) |> draw
 ```
 
+Don't restrict yourself to standard visualizations!  You can use all of AlgebraOfGraphics' features.
+
+Let's plot each X-slice, faceted in Y:
+
+```@example Makie
+data(A) * mapping(X, :data; layout = Y => nonnumeric) * visual(Lines) |> draw
+```
 
+This approach is also applicable to `DimStack`s, since they also convert to DimTables.  Let's see an example here.
+
+We'll construct a DimStack with the `:data` layer being our DimArray `A`, and an X-only variable `:color` that we'll use to color the line.
+
+```@example Makie
+color_vec = DimVector(1:10, X)
+ds = DimStack((; data = A, color = color_vec))
+
+data(ds) * mapping(X, :data; color = :color, layout = Y => nonnumeric) * visual(Lines) |> draw
+```
 
+!!! note
+    If you wish to subset your DimArray, you can't pass selectors like `X(1 .. 2)` to AlgebraOfGraphics.  
+    Instead, subset the DimArray you pass to `data` - this is a very cheap operation.
 
 ## Test series plots