File formats

All digital file formats are in danger of becoming obsolete. If they do, future software may not be able to read or show the information in the files correctly. One way of countering the risk that a file becomes unreadable is to choose a file format with a high probability of remaining usable in the future. As a general guideline, SND believes that the file formats best suited for long-term preservation and accessibility:

  • are in common usage
  • can be read by multiple software
  • are well documented, meaning that it is possible to find a technical specification which details how information is stored in the format
  • are open/non-proprietary.

Our data management pages you can read more about what you need to consider when you choose a file format.

Data in the SND research data catalogue

In order to help you not having to figure out whether a certain format fulfils these criteria, SND has evaluated a number of preservation formats and created a list of formats which should be used for research data that are made accessible in the SND research data catalogue. The table is not a complete list of formats that can be used for research data, and will change as technical circumstances change. If you want to describe data in a file format that is not on the list, please contact SND:

Preferred formats are those that SND considers to have the greatest probability of maintaining accessibility and readability in the future.

Accepted formats are commonly used formats that have good prospects of being readable in the long term. SND strongly recommends the preferred formats, but will also approve of data in the accepted formats.



Preferred formats

Accepted formats

Text documents

  • ASCII (.txt)
  • MS Word (.docx)
  • OpenDocument Text (.odt)
  • PDF/A (.pdf)
  • Unicode (.txt)
  • MS Word (.doc)
  • PDF (.pdf)
  • Rich Text Format (.rtf)

Markup language

  • HTML (.html)
  • JSON (.json)
  • XML (.xml)
  • SGML (.sgml)
  • Markdown (.md) 


  • CSV (.csv)
  • MS Excel (.xlsx)
  • OpenDocument Spreadsheet (.ods)
  • MS Excel (.xls)
  • OOXML (.docx, .docm)
  • PDF/A (.pdf)


  • CSV (.csv)
  • SIARD (.siard)
  • SQL (.sql)
  • dBase III or IV (.dbf)
  • Filemaker Pro (.fmp7, .fmp12)
  • MS Access (.mdb, .accdb)
  • OpenDocument Base (.odb)

Statistical data

  • OpenDocument (.ods)
  • SPSS portable (.por)
  • SPSS SAV (.sav)
  • STATA (.dta)
  • CSV (.csv)
  • MS Excel (.xls, .xlsx)
  • R (.rdata, .rda)
  • SAS (.sas)
  • SAS transport (.xpt)

Image (raster/bitmap)

  • Adobe Digital Negative format (.dng)
  • DICOM (.dcm)
  • PNG (.png)
  • TIFF (.tif, .tiff)
  • Adobe Photoshop document file (.psd)
  • JPEG (.jpg, .jpeg)
  • JPEG 2000 (.jp2, .jpx)
  • Raw image data (various formats)

Image (vector)

  • SVG (.svg)
  • Adobe Illustrator (.ai)
  • AutoCAD Drawing Interchange Format (.dxf)
  • EPS (.eps)
  • PDF/A (.pdf)
  • PDF (.pdf)
  • WebCGM 2.1 (.cgm)


  • Lossless AVI (.avi)
  • Matroska (.mkv)
  • MPEG-1 (.mpg, .mpeg, …)
  • MPEG-2 (.mpg, .mpeg, …)
  • MPEG-4 H.264 (.mp4)
  • MPEG-4 Part 14/MP4 (.mp4)
  • Audio Video Interleave (.avi)
  • DivX (.divx)
  • MXF (.mxf)
  • Motion Jpeg 2000 (.mj2, .mjp2)
  • QuickTime (.mov)


  • AIFF (.aif, .aiff)
  • Broadcast Wave Format (.bwf)
  • FLAC (.flac)
  • Matroska (.mka)
  • MPEG-1 (.mpg, .mpeg, …)
  • MPEG-2 (.mpg, .mpeg, …)
  • Waveform Audio (.wav)
  • AAC (.aac)
  • Audio Video Interleave (.avi)
  • MP3 (.mp3)
  • MPEG-4 Part 14/MP4 (.mp4)
  • Ogg Vorbis (.ogg)
  • Opus (.opus)
  • Speex (.speex)

Geographical information (GIS)

  • Digital Elevation Model (DEM) Format (.dem)
  • Geographic Markup Language (.gml)
  • Keyhole Markup Language (.kml)
  • GeoTIFF (.tif, .tiff)
  • CSV (.csv)
  • GeoJSON (.geojson)
  • OGC GeoPackage (.gpkg)
  • ArcInfo Interchange (.e00)
  • ESRI GRID (.adf, .asc, .grd)
  • ESRI Shapefile (.shp)
  • LAS (LASer) File Format
  • MapInfo (.tab, .dat)
  • MapInfo Interchange Format (.mif, .mid)


  • W3C standards


3D data

  • COLLADA (.dae)
  • CSV (.csv)
  • Universal 3D (.u3d)
  • Wavefront OBJ file (.obj)
  • X3D (.x3d)
  • 3DS (.3ds)
  • AutoCAD Drawing Interchange Format (.dxf)
  • Autodesk 3D asset exchange format (.fbx)
  • Stanford polygon file format (.ply)
  • STL 2.0 (.stl)
  • Virtual Reality Modelling Language (.vrml)