BLT file format
OpenTally accepts ballot data in the BLT file format, as described by Hill, Wichmann & Woodall for their implementation of Meek STV. The BLT file format is also used by OpenSTV/OpaVote, Lundell's Droop and Otten's eSTV (where it is known as a DAT data transfer file).
The file format is as follows:
4 2 -2 3 1 3 4 0 4 1 3 2 0 2 4 1=3 0 1 2 0 2 2=4=3 1 0 1 3 4 2 0 0 "Adam" "Basil" "Charlotte" "Donald" "Title"
The first line (
4 2) indicates that there are 4 candidates for 2 vacancies.
The second line (
-2), which is optional, indicates that the 2nd candidate (Basil) has withdrawn. Multiple withdrawn candidates may be specified on this line, e.g.
-2 -3 -4.
The third line (second, if there are no withdrawn candidates) begins the ballot data.
3 1 3 4 0 indicates that there were 3 ballots which voted, in order of preference, for the 1st candidate (Adam), then the 3rd candidate (Charlotte), then the 4th candidate (Donald). An
= indicates that multiple candidates were ranked at the same preference. A
0 optionally indicates the end of the list of preferences.
The end of the list of ballots must be indicated with a single
The next lines give the names of the candidates, up to the number of candidates specified on the first line (in this case, 4). Each candidate's name, unless a single word, must be surrounded by quotation marks.
The final line gives the name of the election, which, unless a single word, must be surrounded by quotation marks.
Newlines are optional, but if not provided, the
0 at the end of each ballot's preferences is mandatory.