I was given 8 files that supposedly contain GIS data. They appear to be a file split into parts and are named: "stuff.zip [1_8].dat" , "stuff.zip [2_8].dat" , etc..

I tried stripping the ".dat" but that didn't help to unzip the files. I know this is probably a zip problem rather than GIS problem but I was hoping someone might recognize how the heck someone would send GIS data in this form. Opening with a text editor shows the following type of data, any idea if this is an old ESRI file type that was given the wrong extension or something? Thanks for any ideas.


Edit: it looks like this is a problem with how the data was encoded for the email message? After searching around a bit, I'm not sure how to deal with this. Obviously this is in the completely wrong forum at this point but thanks for any help. Here is a header before the alphanumeric string begins:

Content-Type: application/octet-stream; name="stuff.zip" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="stuff.zip"

closed as off-topic by whuber Apr 17 '14 at 15:09

  • This question does not appear to be about geographic information systems (GIS) within the scope defined in the help center.
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  • Looks like it's a single zip split over many files. 7 zip or winRAR can normally open those. – Nathan W Apr 17 '14 at 13:09
  • Yea, unfortunately I can't get them to unzip. Oh well, just thought maybe they were named incorrectly and were actually some sort of GIS filetype. Thanks. – RossV Apr 17 '14 at 13:18
  • This question appears to be off-topic because, although it originally seemed to be about GIS, it turned out to concern e-mail encoding and zip formats. – whuber Apr 17 '14 at 15:09

I use 7zip, can only comment on using that to reassemble split archive.

All 8 files must be in the same directory. I just created a split archive of 14 parts (10 MB each) from one image gallery (140 MB) and then put it back together to test the process.

Select first file (stuff.zip.[1_8].dat in your case), right click, select 7zip, "Extract to".

If that does not work, create a backup of your 8 files and try removing .dat part from all the file names and then reassembling the archive.


  • I was able to recombine into a single file, but 7-zip still can not open the file. I guess because it is just plain text? Not sure what to use to decode into something useful. Thanks for the help recombining the file though – RossV Apr 17 '14 at 14:29
  • Does that recombined file have an extension? It might not be an archive, it could be the actual file, but with lost extension. – afaf12 Apr 17 '14 at 14:41
  • I renamed the files to end with ".zip.001" ".zip.002" etc.. Then opened the 001 file with 7zip. That gave me the combined .zip file. – RossV Apr 17 '14 at 14:47
  • @RossV A google search just lead me to this tool which can be used to identify files with no extension: mark0.net/soft-trid-e.html Have not used it myself, but looks promising. Maybe give it a shot. – afaf12 Apr 17 '14 at 14:49
  • mark0.net/soft-tridnet-e.html for the version with GUI. TrIDNet and the "TrID XML defs" must be put in the same directory. – afaf12 Apr 17 '14 at 15:07

If you use 7zip and select the correct option it will merge your dat file chunks

  • 2
    Care to elaborate further on "the correct option", maybe a screenshot or two? – elrobis Apr 17 '14 at 14:01
  • comments above contain the correct answer; put files in same folder, double click first file, when asked by windows what program to use select 7zip. – lewis Apr 22 '14 at 19:44

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