Most spatial datasets are too large to mail successfully, but if the resulting zip file is < 6Mb, then it should transfer cleanly. I've had issues with WinZip performing nl->cr,lf conversion on binary data on extract, or not preserving the directory structure, but even these are unfortunate settings in the extraction utility, and nothing to do with the data itself. Try using 7Zip , which is a free and fast zip generation and extraction utility. - V
