Purpose of the Dataset These data were gathered as the foundation for a geomorphometric study of barchan dunes. The intent is for the data to be used in bulk (for the law of large numbers) because of randomly distributed measurement errors (see error analysis section in the BarchanDataDescription.docx file). Data for individual dunes should be used with caution. More details are provided in the BarchanDataDescription.docx file. Dataset heading For the BarchanDunes-GeomorphometricData.xlsx file, Column A, name and/or country of dune field; Column B, sample (dune) number (ED and MD refer to Earth dune and Mars dune); W1 and W2 are body width and horn-to-horn width; L1 and L2 are body length and total length; H1 and H2 are the horn lengths; and latitude and longitude are in decimal degrees. Negative values for latitude and longitude represent coordinates in the southern or western hemispheres, respectfully.