Update to_do_data_analysis.md

generic corrections added

src/transformation_to_layer1/to_do_data_analysis.md

@@ -57,6 +57,8 @@ Please add any observed data issues to this file
 * Add list with structure similar to PIRs, in which specific data updates by FSCC can be listed (along with their reason and a "change_date"). These can then be applied in a way similar to updated values in the checked PIRs.
 * Convert script into a function, in which you can choose the survey form (so_som, so_pfh, s1_som, s1_pfh) and the variable to calculate stocks from. Different methodological decisions (e.g. about internal gap-filling opportunities) should be changeable via function input variables. List these important methodological variables and their options. A file with this methodological information should be exported as metadata in the output.
 
+### LESSONS LEARNED FROM MANUAL CORRECTIONS:
+* in s1_som files, for all MINERAL horizons, set organic_layer_weight==NA if bulk density value is given.  
 
 
 ~~## TO DO - Checked PIRs~~