File formats
The choice of the appropriate file format is crucial for the accessibility and reusability of your data.
- An open format is a file format that can be used by anyone, as its specifications are publicly available.
- A proprietary (or closed) format is a format that is tied to a particular vendor's software. When the software is no longer available, the files usually become unusable and/or unreadable.
We therefore recommend that you save your data in an open format whenever possible. And if converting to an open format will alter the form of the document, then it is worth keeping the data in both proprietary and non-proprietary formats.
Recommended practices
The following table lists the recommended and acceptable formats for various types of data.
Please note that this list is not exhaustive and only includes the most common extensions. The format corresponding to these extensions is available here.
| Type of data | Recommended formats | Acceptable formats | Not recommended |
|---|---|---|---|
|
Qualitative data; Texts |
.txt
.xml .pdf/A .odt .odm .tex .md .htm .odf |
.html
.docx .pptx .rtf .eps |
.doc
.ppt .dvi .ps |
|
Quantitative data; Tabular data with extensive metadata Data comprising variable labels, labelling codes and defined missing values, in addition to the data matrix. |
.csv
.por
.ddi .xml .hdf5 delimited text and command file (SPSS, Stata, SAS, etc.) |
.txt
.html .tex .sav .dta .mdb / .accdb |
|
|
Quantitative data; Tabular data with minimal metadata Data that may or may not include column headers or variable names, but which contain no other metadata or annotations. |
.csv
.tab .ods .sql .tsv |
.txt |
.xls / .xlsb
|
| Image data |
.tif (6.0 uncompressed)
.png .svg .jpeg .fits |
.jpg / .jp2
.gif .tif / .tiff .raw .psd .bmp |
.indd
.ait .psd .spc .lif |
| Audio data |
.wav
.flac .ogg .mxl .midi |
.mp3 |
|
| Video data |
.mp4
.mj2 .avi .mkv |
.avchd
.webem .ogv .ogg |
.wmv
.mov .qt |
|
Geospatial data Vector and raster data |
.shp
.shx .dbf Tabular GIS attribute data .gml .netcdf .postgis .geojson |
.mdb
.mif .kml .ai .dxf .svg binary formats of GIS and CAD packages |
|
| Structures and 3D images |
.x3D
.x3DV .x3DB .pdf3D .pov .pdbml |
.dwg
.dxf .pdb |
.pxp
|
| Code |
.r
.py .ijpnb .rstudio .rmd .netcdf .aiml |
.sdd
|
.mat |
| Documentation and scripts |
.rtf
.pdf/A .pdf/UA .xhtml .html .odt |
.txt |
(Source: UK Data Service and EPFL FastGuide #4 - File Formats)
To learn more
- Video "Data Science for all": Preparing your data for archiving (on Mediaserver)
- Research Data Management Fast Guide #04, "File Formats", from EPFL