Updates to how to manually define custom GeoRegions directly in files

docs/src/tutorials/projects/files.md

@@ -1,5 +1,105 @@
-# Reading in a file with a list of Custom `GeoRegion`
+# Files of custom `GeoRegion`s
 
+This page gives a brief introduction into how to **manually** defined custom `GeoRegion`s in their respective files.
+
+## `RectRegion` and `TiltRegion` Files
+
+Manually defining a `RectRegion` or a `TiltRegion` in the `rectlist.txt` and `tiltlist.txt` files is relatively simple. Simple follow the order of the headers in the respective files.
+
+!!! warn "Name of GeoRegion"
+    To manually define the `name` of the `GeoRegion`, replace all **spaces** with `-`. For example, "Southern South America" would be written as "Southern-South-America" in the text file. Please see `joinpath($(GeoRegions.geodir),"giorgi.txt")` for examples.
+
+### Example in rectlist.txt
+
+In `rectlist.txt`, the header is
+
+```
+# RectRegion
+# List of RectRegion GeoRegions
+# (1)ID, (2)pID, (3)N, (4)W, (5)S, (6)E, (7)Description
+```
+
+Therefore in order to define a `RectRegion` directly in the filed, we do, for example
+
+```
+TST, GLB, 70, -60, -20, 130, Test-RectRegion-Manual-Add
+```
+
+which is the same as
+
+```julia
+RectRegion("TST","GLB","Test RectRegion Manual Add",[70,-20,130,-60])
+```
+
+!!! warning "Order of Bounds"
+    Note that in the `RectRegion()` function, the bound is ordered in `[N,S,E,W]`, but when directly inputing into file, it is in the order `N, W, S, E`.
+
+### Example in tiltlist.txt
+
+In `tiltlist.txt`, the header is
+
+```
+# TiltRegion
+# List of TiltRegion GeoRegions
+# (1)ID, (2)pID, (3)X, (4)Y, (5)ΔX, (6)ΔY, (7)θ, (8)Name
+```
+
+Therefore in order to define a `TiltRegion` directly in the filed, we do, for example
+
+```
+TST, GLB, 30, 40, 100, 5, 10, Test-TiltRegion-Manual-Add
+```
+
+which is the same as
+
+```julia
+TiltRegion("TST","GLB","Test TiltRegion Manual Add",[30,40,100,5,10])
+```
+
+## `PolyRegion` Files
+
+Manually defining a `PolyRegion` in `polylist.txt` is in some ways very tricky, and honestly it is best done by calling `PolyRegion(...,save=true)`. However, should you wish to manually define a `PolyRegion` directly in a file, the header is
+
+```
+# PolyRegion
+# List of PolyRegion GeoRegions
+# (ID, pID, Name), X, Y
+
+```
+
+!!! warning "Additional empty lines"
+    The additional empty line between the header and the `GeoRegion`s below it, and between the individual `PolyRegion`s being defined, is **essential**. GeoRegions.jl reads a file containing `PolyRegion`s on a **_line-by-line_** basis and thus empty lines are very important.
+
+
+Following the header, we have the following lines
+
+```
+RegID 
+RegX  
+RegY  
+```
+
+And then
+* Following `RegID`, we should fill in the `(ID, pID, Name)`, separated by **spaces**.
+* Following `RegX`, we should fill in the **longitude** vector
+* Following `RegY`, we should fill in the **latitude** vector
+
+For example, we have
+```
+RegID AR6_ENA, GLB, Eastern-North-America       # (ID, pID, Name)
+RegX  -70.0, -90.0, -90.0, -50.0, -77.0, -70.0  # Longitude vector
+RegY  25.0, 25.0, 50.0, 50.0, 31.0, 25.0        # Latitude vector
+```
+
+Which is the same as defining
+
+```julia
+PolyRegion(
+    "AR6_ENA","GLB","Eastern-North-America", # (ID, pID, Name)
+    [-70.0,-90.0,-90.0,-50.0,-77.0,-70.0],   # Longitude vector
+    [25.0,25.0,50.0,50.0,31.0,25.0]          # Latitude vector
+)
+```
 
 ## Listing GeoRegions inside Custom Files