The mapfile is a metadata text table containing sequencing and experimental information of each sample.
A mapfile can simply be created as Excel table and then saved as tab delimited text file.
The header line needs to look like:
#SampleID BarcodeSequence LinkerPrimerSequence Treatment ... Description
S01 control gut_sample_01
S02 diet_A gut_sample_02
S03 diet_B gut_sample_03
#SampleID (starting with #) as first column
BarcodeSequence (keep empty if sequence does not contain barcodes)
Treatment (or Environment, etc) - main experimental condition of each sample
... additional columns of sample metadata
Description as last column (original sample name)
bold names are required columns in the mapfile metadata table.
validate_mapping_file.py -m metadata.csv -o validation_outcomes
validation results: validation_outcomes/metadata.html (to open in web-browser)
http://qiime.org/documentation/file_formats.html#metadata-mapping-files