topic Re: Emailing File Geodatabases in Data Management Questions

Emailing File Geodatabases

DeviiRao — Tue, 28 Sep 2010 00:41:21 GMT

I was recently told I should stop using shapefiles and start using file geodatabases. One reason given was that it's easier to share/email file geodatabases. However, when I tried to email a file geodatabase I created, I have to send far more files than I would have for a shapefile. Am I missing something?

Re: Emailing File Geodatabases

VinceAngelo — Tue, 28 Sep 2010 02:45:35 GMT

Shapefiles suffer from a number of defects, most related to the limitations of dBase:
1) Lack of numeric NULLs
2) Lack of second precision on date types (limited to YYYY-MM-DD)
3) Column name clipping at 11 characters
4) 254 character limit on strings (and lack of NSTRING, and fixed width transfer)

File geodabases have none of these issues.

For consistency's sake (with either format), you should be transferring zipfiles, not
individual file components.

- V

Re: Emailing File Geodatabases

DeviiRao — Tue, 28 Sep 2010 15:47:38 GMT

Thanks. So if I understand correctly...

1) A shapefile might have upto 7 associated files.
2) A personal geodatabase will have just one file (an .mdb file)
3) A file geodatabase containing one feature class might have around 40 associated files.

When emailing shapefiles or file geodatabases, it's best to put all associated files into a zipfile. When emailing a personal geodatabase, it's just one file and doesn't necessarily need to be put in a zipfile. So, file geodatabases don't have the benefit of being housed in one encompassing file like the personal geodatabase.

Is that correct?

Re: Emailing File Geodatabases

VinceAngelo — Tue, 28 Sep 2010 22:48:36 GMT

Given that base64 MIME encoding is going to increase file size by 1/3, it's probably wise to
always zip before e-mailing data (including .mdb files) -- this will also give you a way to
detect corruption in transfer.

The one file solution has a drawback as well -- File geodatabases do not have any real size
limitation, while PGDB are limited to 2Gb.

- V

Re: Emailing File Geodatabases

DeviiRao — Tue, 28 Sep 2010 22:57:21 GMT

Thanks for the info.