diff --git a/data/landbouwstreken/README.txt b/data/landbouwstreken/README.txt
index 284e0c93..e9e0f6d9 100644
--- a/data/landbouwstreken/README.txt
+++ b/data/landbouwstreken/README.txt
@@ -1,5 +1,7 @@
 This folder contains agricultural regions of Flanders.
 
+- Lbstrbel.shp
+  - Agricultural regions of Belgium
 - Lbstrvl.gpkg
   - Agricultural regions of Flanders
 
diff --git a/data/processed/.gitignore b/data/processed/.gitignore
index 9108ec5f..8337af97 100644
--- a/data/processed/.gitignore
+++ b/data/processed/.gitignore
@@ -8,4 +8,5 @@ steekproef_piloot_avimap.tsv
 steekproef_piloot_avimap.yml
 trend_aup.tsv
 trend_aup.yml
+!README.txt
 !.gitignore
diff --git a/data/processed/README.txt b/data/processed/README.txt
new file mode 100644
index 00000000..05810921
--- /dev/null
+++ b/data/processed/README.txt
@@ -0,0 +1,19 @@
+This folder contains processed data files.
+
+- weidestreek_perimeters.gpkg
+  - perimeters of weidestreek agricultural region used as input for sampling frame
+  - for creation see source/markdown/steekproefontwerp_weidestreek.Rmd
+- za_kp_po_perimeters.gpkg
+  - perimeters of zandstreek, kempen, polders agricultural regions used as input for sampling frame
+  - for creation see source/markdown/steekproefontwerp_zandstreek.Rmd, source/markdown/steekproefontwerp_kempen.Rmd, source/markdown/steekproefontwerp_polders.Rmd
+- zandleemstreek_perimeters.gpkg
+  - perimeters of zandleeemstreek, leemstreek agricultural regions used as input for sampling frame
+  - for creation see source/markdown/steekproefontwerp_zandleemstreek.Rmd, source/markdown/steekproefontwerp_leemstreek.Rmd in MAS pilot repository
+
+Files written by steekproefontwerp_XXX.Rmd (see above) where XXX is the agricultural region.
+
+- .tsv and .yml files are under version control GitHub
+- .geojson and .kml files
+
+MAS pilot repository: https://github.com/inbo/mas-piloot
+MBAG MAS repository: https://github.com/inbo/mbag-mas
\ No newline at end of file