Which file formats should I use?
Question
What are the preferred file formats to use for storage of primary and secondary data and documents?
Answer
The strongly preferred way of storing all data is as tab- or comma-delimited text files with variable names in the first line, with an associated R script that reads the data file, as this makes data robust towards future changes in software and data file formats. For other data types, consider using the suggested file formats below (based on the KNAW-DANS Preferred Formats overview, January 2025) for similar reasons of compatibility and future accessibility:
| Data type | Preferred format | Non-preferred (acceptable) format |
| Documents | PDF/A (.pdf) Unicode TXT (.txt) OpenDocument Text (.odt) |
MS Word (.doc, .docx) Rich Text File (.rtf) PDF (.pdf) Non-unicode TXT (.txt) |
| Spreadsheets | OpenDocument Spreadsheet (.ods) Comma separated values (.csv) |
PDF/A (.pdf) MS Excel (.xls,.xlsx) |
| Databases | ANSI SQL (.sql) Comma separated values (.csv) |
MS Access (.mdb, .accdb) dBase III or IV (.dbf) |
| Statistical data | R SPSS (.dat/.sps) |
SPSS portable (.por) SAS transport (.sas) |
| Audio | BWF (.bwf) MXF (.mxf) Matroska (.mka) FLAC (.flac) OPUS |
WAVE (.wav) MP3 (.mp3) AAC (.aac, .m4a) AIFF (.aif, .aiff) OGG (.ogg) |
| Video | MXF (.mxf) Matroska (.mkv) |
MPEG-4 (.mp4, .m4a, .m4v, …) MPEG-2 (.mpg, .mpeg, .m2v, .mpg2, …) AVI (.avi) QuickTime (.mov, .qt) |
| Pictures (raster) | JPEG (.jpg, .jpeg) TIFF (.tif, .tiff) PNG (.png) JPEG 2000 (.jp2) DICOM (.dcm) |
|
| Pictures (vector) | Scalable Vector Graphics (.svg) | Adobe Illustrator (.ai) PostScript (.eps) WMF/EMF (.wmf, .emf) |
| Geographical Information Systems (GIS) | GML (.gml) MIF/MID (.mif/.mid) GeoJSON (.json) GeoPackage (.gpgk) |
Esri Shapefiles (.shp & related files) MapInfo (.tab & related files) KML (.kml, .kmz) Esri Geodatabase (.gdb) Project files / Workspaces (.mxd, .wor, .qgs) |
| Georeferenced images | GeoTIFF (.tif, .tiff) | TIFF World File (.tfw & .tif, possibly with additional files) JPEG World File (.jgw & .jpg, possibly with additional files) ERDAS IMAGINE File Format (.img) |
| Raster GIS | ASCII GRID (.asc, .txt) | Esri GRID (.grd & related files) Surfer Grid (.grd; .srf) ERDAS IMAGINE File Format (.img) |
| Last modified: | 12 February 2025 5.00 p.m. |