Preparing-the-data-for-use-with-the-IDE.md

@@ -5,7 +5,7 @@ The primary requirement is a table of data points derived from images and a dire
 
 ### **Data points**
 ##### Format
-Image-derived data are expected to be in table format with data points in rows and stored in a **tab- or comma-separated text file using ASCII or UTF-8 encoding**. The table must have **column headers with unique column names** and all columns must have a header. Cells can be enclosed in double quotes but not in single quotes. For numbers, the decimal separator must be . (dot) and no separator for thousands is allowed.  
+Image-derived data are expected to be in table format with data points in rows and stored in a **tab- or comma-separated text file using ASCII or UTF-8 encoding**. The table must have **column headers with unique column names** and all columns must have a header. Column names must start with a letter and only contain alphanumerical characters plus underscore and dot. Cells can be enclosed in double quotes but not in single quotes. For numbers, the decimal separator must be . (dot) and no separator for thousands is allowed. 
 If the data is distributed across multiple tables in the same directory, these can be combined into one table with the following shell commands run in the directory containing the tables:  
 `(head -1 fileA.csv && tail -n +2 -q file*.csv) >> ../table.csv`  
 or