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Research Data Management: File Format Dictionary

The Research Data Management Portal is designed to provide guidance, best practices, and resources on the steps within the research data lifecycle and its correlation to the requirements of established data management practices.

Overview

National Transportation Library File Format Dictionary

Overview

Below you will find File Format descriptions that were created by NTL Data Services staff while cataloging previous datasets. They are organized into alphabetical order for ease of navigation. If you have suggestions for additions, please contact NTLDataCurator@dot.gov.

When creating file descriptions you can use the below resources:

Navigation

A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z

A

  • .accdb: ACCDB files are Microsoft Access Database files. These files replace .mdb files that were used by Microsoft Access prior to the 2007 version for its main database files. They can be viewed using Microsoft Access or they can be converted to .CSV files. The .csv, Comma Separated Value, file is a simple format that is designed for a database table and supported by many applications. The .csv file is often used for moving tabular data between two different computer programs, due to its open format. Any text editor or spreadsheet program will open .csv files. (for more information on .accdb files and software, please visit https://www.file-extensions.org/accdb-file-extension).
  • .aiff: A .aiff file is a high-quality audio file developed by Apple. These files can be played using most standard audio and visual software, such as Windows Media Player or VLC Media Player (for more information on .aiff files and software, please visit https://www.file-extensions.org/aiff-file-extension). 
  • .asset: The file extension .asset is mainly associated with the Unity game development tool. The typical .asset file contains textures, assets, shader and other related data for 3D models (for more information on .asset files and software, please visit https://www.file-extensions.org/asset-file-extension).
  • .avi: The file format .avi is an audiovisual file format. This file can be opened using most video players, including VLC media player (for more information on .avi files and software, please visit https://www.file-extensions.org/avi-file-extension).

B

  • .bak: The .bak file extension is traditionally used for backing up software. This format is used by various programs and software (for more information on .bak files and software, please visit https://www.file-extensions.org/bak-file-extension).
  • .bat: Batch Files execute commands in Microsoft Command Prompt. These files can be run using the computer's command executer or be viewed using the open-source program Notepad. (for more information on .bat files and software, please visit https://www.file-extensions.org/bat-file-extension).
  • .bib: The .bib file extension is associated with BibTex, a reference management software that allows users to create a bibliography (for more information on .bib files and software, please visit https://www.file-extensions.org/bib-file-extension-bibtex-document).
  • .bmp: The .bmp file extension is the bitmap file format. Bitmap images, also known as rastar files, are standard, non-compressed bit-mapped graphics format used by Windows and GIS software (for more information on .bmp files and software, please visit https://www.file-extensions.org/bmp-file-extension).

C

  • .cae: The .cae file is a file used for computer-aided engineering (CAE) models from the Abaqus software (for more information on .cae files and software, please visit https://www.file-extensions.org/cae-file-extension).
  • .cjs: The .cjs file extension is a Common JavaScript file  that contains JavaScript Language source code. It is possible to open these files using any software that can open and view JavaScript, such as Visual Studio Code (for more information on .cjs files and software, please visit https://www.file-extensions.org/js-file-extension). 
  • .cmd: CMD files are command files that can be used by a variety of software (for more information on .cmd files and software, please visit https://www.file-extensions.org/cmd-file-extension). 
  • .config: The .config file extension is commonly used for configuration and settings files. Usually plain text file that can be edited in any text editor. It is also used in many .NET framework based applications (for more information on .config files and software, please visit https://www.file-extensions.org/config-file-extension).
  • .cs: The .cs file extension is associated with Microsoft Visual C# (C SHarp) C# .NET development software. The .cs files are source code files created in this language (for more information on .cs files and software, please visit https://www.file-extensions.org/cs-file-extension).
  • .csl: The .csl file extension is associated with CorelDRAW, a vector graphics editor developed and sold by Corel Corporation (for more information on .csl files and software, please visit https://www.file-extensions.org/csl-file-extension).
  • .css: Cascading Style Sheets format is a file format used to format the look of html web pages. The files help keep the look of a webpage or webpages uniform (for more information on .css files and software, please visit https://www.file-extensions.org/css-file-extension).
  • .csv: The .csv, Comma Separated Value, file is a simple format that is designed for a database table and supported by many applications. The .csv file is often used for moving tabular data between two different computer programs, due to its open format. The most common software used to open .csv files are Microsoft Excel and RecordEditor, (for more information on .csv files and software, please visit https://www.file-extensions.org/csv-file-extension).

D

  • .dat: The file extension .dat is traditionally used by many various applications or programs for their data or resource files (for more information on .dat files and software, please visit https://www.file-extensions.org/dat-file-extension).
  • .dll: The .dll file extension is commonly used for so called dynamic-link libraries, modules that contain data and other functions that can be linked to another module, for example executables (for more information on .dll files and software, please visit https://www.file-extensions.org/dll-file-extension).
  • .do: The .do file type is a batch analysis file for Java servlets used by the software Stata. Stata is popular statistical analysis software for Microsoft Windows operating system. To open these files, open them in Stata or any web browser or text editor (for more information on .do files or software, please visit https://www.file-extensions.org/do-file-extension-stata-batch-analysis-data).
  • .docx: The .docx file is a Microsoft Word file, which can be opened with Word and other free word processor programs, such as Kingsoft Writer, OpenOffice Writer, Apache OpenOffice, and ONLYOFFICE.
  • .dpt: The DPT file extension stores data from various programs. This file can be opened using programs such as Microsoft Excel or open source programs such as Notepad. 
  • .ds_store: Desktop Services Store files, or DS_STORE Files, are Mac OS files that stores desktop attributes such as icons and colors. They are only used by Mac OSs and don't require additional software (for more information on .ds_store files and software, please visit https://www.file-extensions.org/ds_store-file-extension).
  • .dta: DTA files are files that store data. In most cases, .dta filesare only used for internal purposes and are not meant to be a data exchange format. In most cases, these files relate to the software Stata. These files can be opened by Stata or with the open-source software R (for more information on .dta files or software, please visit https://www.file-extensions.org/dta-file-extension). 
  • .dwg: DWG files are files created in AutoCAD, a CAD software for Microsoft Windows and Apple Mac developed by Autodesk Incorporated. Typically used in CAD drawings, this file format stores two and three dimensional data (for more information on .dwg files or software, please visit https://www.file-extensions.org/dwg-file-extension). 

E

  • .enl: The .enl file type is a bibliographic file format associated with EndNote bibiographic reference software (for more information on .enl files and software, please visit https://www.file-extensions.org/enl-file-extension). 
  • .esp: The .esp file extension is associated with the Eclipse, an integrated development environment that allows users to create applications for Windows, Linux, Mac, JAVA, Android and other platforms (for more information on .esp files and software, please visit https://www.file-extensions.org/esp-file-extension).
  • .exe: The .exe file extension is traditionally used for program executable file since the time of first DOS. There are several versions of this file format, but all serve the same purpose - to start a program (for more information on .exe files and software, please visit https://www.file-extensions.org/exe-file-extension).
    • Warning: Executable files could contain viruses or other damaging software. They should be ingested with care.
  • .exp: The .exp file type is created by several programs. It can be created by Microsoft Visual C++ to store exported data from C++ projects. It can also be created by CATIA CAD software to export data (for more information on .exp files and software, please visit https://www.file-extensions.org/exp-file-extension-microsoft-visual-c-export-file).

F

  • .faa: The .faa, Fast Sequence, file An FAA file stores a record of one or more nucleic acid or protein sequences saved in the FASTA format. Each sequence includes an identification code and the sequence in plain text. Various DNA sequencing applications support the format (such as EMBOSS, Clustal Omega, and Biostrings), and text and source code editors can also open the format (for more information on .faa files and software, please visit: https://fileinfo.com/extension/faa).
  • .fig: The .fig file extension is associated with Fortran, a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing. (For more information on .fig files and software, please visit https://www.file-extensions.org/fig-file-extension).
  • .frm: The .frm file type are usually associated with MySQL as database metadata file. Each .frm file has the same name as the SQL table (for more information on .frm files and software, please visit https://www.file-extensions.org/frm-file-extension). 
  • .fzp: The .fzp file extension is associated with the Fritzing, a software for Microsoft Windows, macOS (Mac OS X) and Linux operating systems. The .fzp file contains custom part data for Fritzing (for more information on .fzp files and software, please visit https://www.file-extensions.org/fzp-file-extension-fritzing-custom-part).

G

  • .gif: The .gif file extension is standard bit-mapped graphics file format very widespread on Internet, which was originally developed by CompuServe in the late 1980s. Files with the GIF extension can be viewed through the local photo viewing software or in the web browser.
  • GIS Software file formats: The following file types are standard for GIS mapping software: AUX, CSF, DBF, PRJ, SBN, SBX, SGML, SHP, LOCK, SHX, CSF, CPG, LYR, MXD, FDBINDEXES, GDBTABLE, GDBTABLX, ATX, SPX. Because the files pertain to map layers and images, they are best viewed using the software that the team used or with any open source 2D and 3D mapping software. 
    • .dbf: The .dbf file extension is traditionally used for database file by many database applications. The original program, which used the DBF file extension for its database, was dBAse. A major legacy of dBase is its dbf file format, which has been adopted in a number of other applications. For example, the shapefile format developed by ESRI for spatial data in a geographic information system uses .dbf files to store feature attribute data (for more information on .dbf files and software, please visit https://www.file-extensions.org/dbf-file-extension). 
    • .prj: The .prj file extension is traditionally used for files that contain projects. Projects contain settings, positions of saved windows, development notes and other raw data that won’t be present in the final file (for more information on .prj files and software, please visit https://www.file-extensions.org/prj-file-extension).  
    • .sbn: The .sbn file extension is mainly associated with ArcView / ArcGIS geography software from ESRI. The .sbn file contains binary spatial indexes, which are used only by ESRI software. The format is not documented and is not implemented by other vendors (for more information on .sbn files and software, please visit https://www.file-extensions.org/sbn-file-extension).  
    • .sbx: The .sbx file extension is associated with the ArcView GIS application used to view and edit GIS data. The .sbx file contains spatial index for read-write shape used to fast access to shape files (for more information on .sbx files and software, please visit https://www.file-extensions.org/sbx-file-extension-arcview-spatial-index-for-read-write-shape-file).  
    • .shp: The .shp file extension is used for ESRI Shape format, a popular geospatial vector data format for geographic information systems software. A shapefile stores non-topological geometry and attribute information for the spatial features in a data set. A shapefile consists of a set of 3 mandatory files, along with several optional files. Each file in the set shares the shapefile name with a different extension. The main file .shp stores the geometry and must always have an index file .shx. A dBASE file .dbf stores all the attributes of the shapes in the main file. Additionally, a projection file .prj stores the projection information (for more information on .shp files and software, please visit https://www.file-extensions.org/shp-file-extension).
    • .shx: A .shx file contains compiled shape data (building blocks, fonts) in form of the machine language compiled version of an .shp file. The file type is associated with AutoCAD, a CAD development platform, developed and sold by Autodesk, Inc (for more information on .shx files and software, please visit https://www.file-extensions.org/shx-file-extension). 
    • .cpg: The .cpg file extension is associated with the ArcGIS, a geographic information system for Microsoft Windows operating system, developed by Esri. The .cpg file stores codepage for identifying a character set (for more information on .cpg files and software, please visit https://www.file-extensions.org/cpg-file-extension-arcgis-codepage).  
  • .gitnore: File extension .gitignore is associated with Git, a version control system developed by Linus Torvalds for various platforms that can run on local machine also as server app. These .gitignore files are text configuration files used by Git used to determine which files and directories to ignore, before user make a commit (for more information on .gitignore files and software, please visit https://www.file-extensions.org/gitignore-file-extension).
  • .gms: The .gms format is a low-level, binary, minimal but generic format for organizing and storing Gesture and Motion Signals in a flexible and optimized way. The GMS format takes into account the minimal features a format carrying movement/gesture data needs: flexible dimensionality, versatile structuration, flexible types of the encoded variables, and spatial and temporal properties of gesture and motion signals (for more information on .gms files and software, please visit https://www.file-extensions.org/gms-file-extension).
  • .gpr: The .gpr file extension is associated with the Babylon Glossary Builder a free application that enables users to create own glossaries using databases stored in Excel or xml files (for more information on .gpr files and software, please visit https://www.file-extensions.org/gpr-file-extension-babylon-glossary-builder-project-file).
  • .graphml: The .graphml file type is a comprehensive XML format for computer graphics (for more information on .graphml files and software, please visit https://www.file-extensions.org/graphml-file-extension). 
  • .gsz: The .gsz file extension is associated with the GeoStudio that is used for geotechnical modeling. The GSZ file contains saved project modeled in the GeoStudio suite. The .gsz file is ZIP container that includes GeoStudio modeling files stored in XML text file format (for more information on .gsz files and software, please visit https://www.file-extensions.org/gsz-file-extension).
  • .gz: The .gz file type is a compressed archive file. These files are used on Unix operating systems for file zipping. They can be unzipped using command prompt or open-source programs such as 7-Zip.
     

H

  • .html: The .html file extension is mainly related to the Hypertext Markup Language that provides means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It is the main language for writing web pages. HTML formats texts, tables, images, and other content that will be displayed on the page that can be viewed using any web browser (for more information on .html files and software, please visit https://www.file-extensions.org/html-file-extension).
  • Hydraulic Software: The OPT, OHL, OTL, PRJ, SUM, IN, OUT TFW, STO, XY, CIF, ELE, GST, LSF, MSK, SMT, IHL, CMF, PRO, IDX, XYS, GAG, and PRN files are all used to model hydraulics using the software Gridded Surface Subsurface Hydrologic Analysis, which is free to download. 

I

  • .info: INFO files are generic text files that can be opened using any text reading software such as Notepad. They are used for a variety of purposes in various programs. 
  • .ini: The .ini file extension is primarily used for configuration files in many Windows applications. A typical .ini file contains set of parameters for the program to be used when it’s started. Probably short for initialize, (for more information on .ini files and software, please visit https://www.file-extensions.org/ini-file-extension)
  • .inp: The .inp file extension is associated with a source code format used by Oracle (for more information on .inp files and software, please visit https://www.file-extensions.org/inp-file-extension-oracle-source-code).
  • .ipynb: The .ipynb file type is a document file created in Jupyter Notebook. These files store browser-based notebooks with support for code, rich text, mathematical expressions, inline plots and other rich media. These files can be opened using the open-source application Jupyter Notebook (for more information on .ipynb files and software, please visit https://www.file-extensions.org/ipynb-file-extension).
     

J

  • .jar: The .jar file extension is mainly associated with Java and used for Java archives. The Java Archive (JAR) file format enables you to bundle multiple files into a single archive file (for more information on .jar files and software, please visit https://www.file-extensions.org/jar-file-extension).
  • .java: The .java file type is associated with the Java programming language and run-time environment available for various platforms. The .java file contains Java source code. These files are in plain text format. This means Java files can be edited in the Java IDE applications and also in standard text editors (for more information on .java files and software, please visit https://www.file-extensions.org/java-file-extension).
  • .jmp: The .jmp file extension is associated with the SAS (Statistical Analysis System), a business analytics and statistical software for Microsoft Windows developed by SAS Institute Inc. The .jmp file stores discovery chart-to-statistics data (for more information on .jmp files and software, please visit https://www.file-extensions.org/jmp-file-extension).
  • .jpg: The .jpg file extension is associated with JPEG (Joint Photographic Experts Group) file format. JPEG is a lossy image compression algorithm that significantly reduces the file size of the original image at the cost of quality. The higher the compression ratio the lower the quality of the .jpg file (for more information on .jpg files and software, please visit https://www.file-extensions.org/jpg-file-extension).
  • .js: The file extension .js is generally mainly related to JavaScript scripting language and used for files that contain JavaScript language source code (for more information on .js files and software, please visit https://www.file-extensions.org/js-file-extension).
  • .json: File extension .json is associated to JavaScript Object Notation file format, a lightweight, text-based, language-independent data interchange format. JSON defines a small set of formatting rules for the portable representation of structured data. It is used by various applications as alternative option to XML file format. The data in a json file are stored in simple text file format and the content is viewable in any simple text editor (for more information on .json files and software, please visit https://www.file-extensions.org/json-file-extension). 

K

  • .k: The .k file format for this project are files associated with the program LS-DYNA, which is crash simulation software made available by Ansys. These files can be accessed using the free version of their software, LS-DYNA Student (for more information on .k files and LS-DYNA software, please visit https://www.ansys.com/products/structures/ansys-ls-dyna). 
  • .kml: A .kml file is a Keyhole Markup Language file that stores geographic data such as lines, images, polygons, and points in a custom layer. Like other markup languages, such as XML and HTML, these files are tag-based with distinct elements and attributes. This type of file and is usually associated with the application Google Earth (for more information on. kmz files and software, please visit https://www.file-extensions.org/kml-file-extension).
  • .kmz: A .kmz file is a compressed file similar to a .zip or .gz file that contains geographic data. KMZ files are a compressed version of .KML files, which are XML-based files for storing geographic data such as lines, images, polygons, and points. This type of file and is usually associated with the application Google Earth (for more information on. kmz files and software, please visit https://www.file-extensions.org/kmz-file-extension).

L

  • .lua: The .lua file extension is commonly associated with so called lua scripts. Lua is a powerful, fast, light-weight, embeddable scripting language. Lua combines simple procedural syntax with powerful data description constructs based on associative arrays and extensible semantics (for more information on .lua files and software, please visit https://www.file-extensions.org/lua-file-extension).
  • .log: The file extension .log is frequently used for .log files. Such files are usually in plain text file format and are used by many programs. A log generally contains a record of which program processes were requested at which times. It is a good bit of information for users and programmers or administrators (for more information on .log files and software, please visit https://www.file-extensions.org/log-file-extension).
  • .las: The .las file type is associated with LAS File format. .las files are written in ASCII with minimal header information and are intended for optical curves only, (for more information on .las files and software, please visit https://www.file-extensions.org/las-file-extension).

M

  • .m: File extension .m is associated with the Objective-C, a general-purpose, object-oriented programming language based on Smalltalk language developed by Apple, Inc (for more information on the .m file type and associated software, please visit https://www.file-extensions.org/m-file-extension).
  • .mat: The .mat file extension is associated with Ox. Ox is an object-oriented statistical system. At its core is a powerful matrix language, which is complemented by a comprehensive statistical library (for more information on the .mat file type and associated software, please visit https://www.file-extensions.org/mat-file-extension-ox-object-oriented-matrix-programming-language-matrix).
  • .md: The file extension .md is among others related to texts and source codes in Markdown markup language. Markdown is a lightweight markup language, to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML) (for more information on .md files and software, please visit https://www.file-extensions.org/md-file-extension).
  • .mdb: MDB files are Microsoft Access Database files. The mdb files were used by Microsoft Access prior to the 2007 version for its main database files. They can be viewed using Microsoft Access or they can be converted to .CSV files. The .csv, Comma Separated Value, file is a simple format that is designed for a database table and supported by many applications. The .csv file is often used for moving tabular data between two different computer programs, due to its open format. Any text editor or spreadsheet program will open .csv files. (for more information on .mdb files and software, please visit https://www.file-extensions.org/mdb-file-extension).
  • .mov: The .mov file extension is a multimedia container format that can store one or more tracks of data such as video, audio, text, and effects. Each track can either contain a digitally encoded media stream, playable using the appropriate codec, or a data reference to a media stream located in another file. These files can be opened using the system's video player. (for more information on the .mov file type and associated software, please visit https://www.file-extensions.org/mov-file-extension).
  • .mp4: The .mp4 file extension is used mainly for the MPEG-4 multimedia file format. These .mp4 files are in a container format defined in the Systems Part of the MPEG-4 standard (ISO 14496-1). The .mp4 files support all kinds of multimedia content (multiple audio streams, video streams, subtitle streams, pictures) and advanced content (called "Rich Media" or "BIFS") like 2D and 3D graphics, user interactivity, DVD-like menus. The MP4 file format is also streamable (for more information on .mp4 files and software, please visit https://www.file-extensions.org/mp4-file-extension).
  • .mtl: MTL files typically store wavefront data in Adobe Photoshop software or stores the mill tool library in the CAD software Mastercam (for more information on .mtl files or software, please visit https://www.file-extensions.org/mtl-file-extension).
  • .myd: The .myd file type is a MySQL database data file that contains table data. These are used in conjunction with .frm and .myi files to create document data tables (for more information on .myd files and software, please visit https://www.file-extensions.org/myd-file-extension). 
  • .myi: The .myi file format is a MySQL index file for data tables. The files are used in conjuction with .frm and .myi files to create data tables (for more information on .myi files and software, please visit https://www.file-extensions.org/myi-file-extension). 

N

  • .nb: The .nb file extensions are Mathematica Notebook files. Notebooks are structured interactive documents that can contain text, graphics, sound, calculations, typeset expressions, and user interface elements. These files can be opened using text editors such as notepad or spreadsheet software such as Microsoft Excel or Google Sheets (for more information on .nb files and software, please visit https://www.file-extensions.org/nb-file-extension).
  • .npz: An .npz file is an uncompressed, zipped format where each file contains one variable. These files are created by NumPy, which is a python library that allows for the creation and use of multidimensional arrays and tensors. These files can be accessed using your default python program. An open-source option includes the software PyCharm. 
  • .nvp: NVP files are files created by NVivo, which is qualitative analysis software. NVivo is intended to help users organize and analyze non-numerical or unstructured data. Open-source alternative to NVivo include Taguette and QualCoder. 

O

  • .obj: Object files, or .obj files, are a standardized file type that contain 3D objects. While they are used by many programs, these files are typically associated with Autodesk (for more information on .obj files and software, please visit https://www.file-extensions.org/obj-file-extension).
  • .opt: The .opt file format is a MySQL file containing various data used by MySQL and compatible tools (for more information on .opt files and software, please visit https://www.file-extensions.org/opt-file-extension). 
  • .out: The file extension .out is used by various applications for generic output file. Some applications, like integrated development environments, use or were using the .out file suffix for outlines or outputs file formats. Some java applications create program logs or reports, system logs as .out file (for more information on .out files and software, please visit https://www.file-extensions.org/out-file-extension).
  • .ovr: The .ovr file type is a geographic pyramid file created by ArcGIS software. An .ovr file is used for storing the pyramid layers for a raster dataset and is a replacement of the .rrd file type (for more information on .ovr files and software, please visit https://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/ovr-pyramid-files.htm). 

P

  • .pack: The .pack file types are Git Packed Objects created using GitHub. These can be opened with any document reader. 
  • .parquet: The parquet file extension is an open source, binary data format generated by Apache Hadoop that stores data in columns. Apache software such as Hadoop, Hive, and Spark all can open and use parquet files. Another option is using the program ParquetViewer to view and query these files. 
  • .pdf: The Portable Document Format (PDF) file format was developed by Adobe Systems and represents two-dimensional documents in a device-independent and resolution-independent format. There are PDF readers available on many platforms, such as Xpdf, Foxit, and Adobe's own Adobe Acrobat Reader. PDF readers/viewers or online services for basic functions are generally free (for more information on .pdf files and software, please visit https://www.file-extensions.org/pdf-file-extension). 

  • .pickle: The .pickle file extension is associated with the Python Pickle module used to implement a fundamental, but powerful algorithm for serializing and de-serializing a Python object structure. The .pickle file stores byte stream representing objects (for more information on .pickle files and software, please visit https://www.file-extensions.org/pickle-file-extension).

  • .plb: The PLB file extension is used by the program STISIM Drive, which is a driving simulator software. These files are playback files from the simulation (for more information on PLB files and STISIM Drive software, please visit https://www.systemstech.com/simulation-products/sti-sim-drive/). 
  • .plk: The plk file extension is associated with ATI Radeon graphic cards, developed by AMD. The plk file stores video driver for ATI Radeon graphic card (for more information on plk files and software please visit https://www.file-extensions.org/plk-file-extension-amd-ati-radeon-video-driver). 
  • .ply: Polygon graphics files, .ply, are simple objects that were designed to be an accessible format for polygon models. These files are typically created in Blender (for more information on .ply files and software, please visit https://www.file-extensions.org/ply-file-extension).
  • .png: The file extension .png is commonly used for images in Portable Network Graphics file format. PNG is a bitmap graphics format similar to GIF, that uses image compression mainly for web purposes (for more information on .png files and software, please visit https://www.file-extensions.org/png-file-extension).
    • Note: .PNG compression is lossless, and is preferred at NTL over .jpg, which uses lossy compression.
  • .pptx: The .pptx file extension is related to Microsoft PowerPoint. PowerPoint is worldwide most popular powerful tool you can use to create and edit dynamic and great-looking presentations. The .pptx files are used for editable slide shows, which are very often used for presentations (for more information on .pptx files and software, please visit https://www.file-extensions.org/pptx-file-extension).
  • .prt: The .prt file extension is typically part of a larger CAD project and contains 3D information. This can be used by many CAD programs, but the file is not interchangeable (form more information on .prt files and software, please visit https://www.file-extensions.org/prt-file-extension).
  • .psd: The .psd file type is a Adobe Photoshop file. This can be modified and viewed using Photoshop (for more information on .psd files and software, please visit https://www.file-extensions.org/psd-file-extension). 
  • .psf: The .psf file type is a common file type, but it mostly associated with the software Microstation by architects, engineers, contractors and GIS professionals (for more information on .psf files and software, please visit https://www.file-extensions.org/psf-file-extension-microstation-plot-specification-file).
  • .py: The .py file extension is commonly used for files containing source code written in Python programming language. Python is a dynamic object-oriented programming language that can be used for many kinds of software development (for more information on .py files and software, please visit https://www.file-extensions.org/py-file-extension).
  • .pyc: The .pyc file type is associated with Python. These .pyc files contain compiled source code of Python programming language scripts (for more information on .pyc files and software, please visit https://www.file-extensions.org/pyc-file-extension).

Q

R

  • .r: The .r file type is related to R programming language. R is a language and environment for statistical computing and graphics (for more information on .r files and software, please visit https://www.file-extensions.org/r-file-extension).
  • .rar: The .rar file extension is a data compression format similar to a zip file, original created by RAR. They can be opened using free programs such as 7-zip or WinRAR (for more information on .rar files and software, please visit https://www.file-extensions.org/rar-file-extension).
  • .raw: The .raw file type is traditionally used for RAW image format, a picture format used by digital cameras for "raw" images taken by the device that are not yet processed to for use. These files are sometimes also called digital negatives because they serve same purpose as negatives in film photography (for more information on .raw files and software, please visit https://www.file-extensions.org/raw-file-extension).
  • .rd: The .rd file type is associated with the R, a comprehensive statistical and graphical programming language used to develop statistical and data analysis software. The .rd file stores documentation for source code (for more information on .rd files and software, please visit https://www.file-extensions.org/rd-file-extension-r-document-file).
  • .rdata: The .rdata file format is associated with R, a comprehensive statistical and graphical programming language used to develop statistical and data analysis software. The .rdata format contains statistcal data used by R that is formatted for the windows environment (for more information on .rdata files and software, please visit https://www.file-extensions.org/rdata-file-extension).
  • .ress: The .ress file extension is related to various computer games based on Unity 3D graphics engine and game development tool, available for various platforms. A .ress file stores textures, assets, shader, materials and other related data for 3D models (for more information on .ress files and software, please visit https://www.file-extensions.org/ress-file-extension).
  • .ris: The .ris file format is a bibliographic file format meant to exchange citation information between bibiographic software. The .ris file is an ASCII text file that contains two letters, two spaces, a dash, a space and the reference for each citation (for more information on .ris files and software, please visit https://www.file-extensions.org/ris-file-extension).
  • .rmd: The .rmd file extension is associated with the RStudio, an integrated development tool for Windows, macOS (OS X) and Linux operating systems, which allows users to create apps with R programming language. The .rmd file stores R markdown data (for more information on .rmd files and software, please visit https://www.file-extensions.org/rmd-file-extension-r-markdown-data).
  • .rproj: The .rproj file extension is associated with the RStudio, an integrated development tool for Microsoft Windows, Apple Mac OS X (macOS) and Linux operating systems used to crate software in R programming language. The .rproj file stores programming project (for more information on .rproj files and software, please visit https://www.file-extensions.org/rproj-file-extension).
  • .rtd: The .rtd file format is used by the software Autodesk Robot Structural Analysis Professional and typically stores designs in the program (for more information on .rtd files and software, please visit https://www.file-extensions.org/rtd-file-extension-autodesk-robot-structural-analysis-professional-design).
  • .rtf: The .rtf file type is used for documents written in Rich Text Format, a text format with some very basic formatting preserved. The .rtf format stores data in plain ASCII text file with additional formatting commands somewhat similar to HTML files (for more information on .rtf files and software, please visit https://www.file-extensions.org/rtf-file-extension).

S

  • .sav: The .sav file extension is associated with SPSS, a predictive analytics software, originally created by SPSS Inc. and now owned and marketed by IBM. The sav file contains data sets created with SPSS, (for more information on .sav files and software, please visit https://www.file-extensions.org/sav-file-extension-spss-data-sets-database).
  • .sed: The .sed file type is associated with the SED (streams editor), a command line utility included in Unix and Unix-based operating systems, that allows users to modify and filter texts (for more information on .sed files and software, please visit https://www.file-extensions.org/sed-file-extension).
  • .sh: An .sh file is a script that can be run with the Bash Unix shell. It contains instructions written in the Bash command language. Users can execute the commands an SH file contains by calling the file in a Bash shell (https://fileinfo.com/extension/sh). 
  • .sha: The file extension .sha is associated with the Unix operating system and used for Unix SHAR self-executing archives. A .sha file is basically a shell script and executing it will recreate the files (for more information on .sha files and software, please visit https://www.file-extensions.org/sha-file-extension).
  • .sldprt: A .sldprt file is a 3D image format created by SolidWorks CAD software.  It must be combined with all other parts to create final object (SLDASM file extension). Blender is an open-source alternative to view these files. (for more information on .sldprt files and software, please visit https://www.file-extensions.org/sldprt-file-extension). 
  • .slx: A .slx file type is a MATlab file that models algorithms and physical systems using block diagrams. MATlab is a free program (for more information on .slx files and software, please visit https://www.file-extensions.org/slx-file-extension-matlab-model). 
  • .slxc: A .slxc file is a Simulink cache file. Simulink is a simulation and modeling software by Mathworks (for more information on .slxc files and software, please visit https://www.file-extensions.org/slxc-file-extension).
  • .spl: The .spl file extension is related to print job file used in previous versions of Microsoft Windows operating system. An .spl file contains commands (for more information on .spl files and software, please visit https://www.file-extensions.org/spl-file-extension).
  • .sqlite: The .sqlite file type is a SQL database file. This file functions as an in-process library and can implement a self-contained, server-less, zero-configuration, transactional SQL database engine (for more information on .sqlite files and software, please visit https://www.file-extensions.org/sqlite-file-extension).
  • .svg: The .svg file extention is an vector image file format for both static and moving images. The format is based on the XML markup language (for more information on .svg files and software, please visit https://www.file-extensions.org/svg-file-extension).

T

  • .tab: A TAB file is a very simple textual data format which allows tabular data to be exchanged between applications that use different internal data formats. These files can be opened using open-source programs such as Notepad or other open source, tabular file readers. These files are more commonly known as .tsv files (for more information on .tab files, please visit https://www.file-extensions.org/tab-file-extension-tab-separated-value). 
  • .tex: The .tex file extension is most notably associated and used for TeX/LaTeX text document files. LaTeX is a document preparation system for high-quality typesetting. The .tex file is a plain text that contains markup conventions, which define document structure. It is most often used for medium-to-large technical or scientific documents, but it can be used for almost any form of publishing (for more information on .tex files, please visit https://www.file-extensions.org/tex-file-extension).
  • .tfw: The .tfw file type is an ArcGIS file type used to store information about GeoTIF files. It typically contains world data and coordinates related to this file (for more information on .tfw files and software, please visit https://www.file-extensions.org/tfw-file-extension).
  • .tif: The .tif file extension is traditionally used for Tagged Image File Format - one of the most widely supported lossless file formats for storing bit-mapped images (both PCs and Macintosh computers). TIFF/IT is a standard for the exchange of digital adverts and complete pages (for more information on .tif files and software, please visit https://www.file-extensions.org/tif-file-extension).
  • .toml: The .toml file type is a basic config, markup file. It is typically created in python environments such as the Python Package Index (for more information on .toml files and software, please visit https://www.file-extensions.org/toml-file-extension).
  • .torrent: The .torrent file format is for peer-to-peer file distribution, usually associated with BitTorrent. These files are not the download itself, but instead the protocol that facilitates the downloading and sharing of files (for more information on .torrent files and software, please visit https://www.file-extensions.org/torrent-file-extension).
  • .tpm: The .tpm file extension is related to Microsoft BitLocker , a program from Microsoft Windows operating system used to encrypt sensitive data and used for files that contain encrypted password data (for more information on .tpm files and software, please visit https://www.file-extensions.org/tpm-file-extension-microsoft-trusted-platform-module-password-data).
  • .trx: The .trx file extension is associated with the Passolo a specialized software localization tool for Microsoft Windows that speeds up the translation of user interfaces. The .trx file contains translation data (for more information on .trx files and software, please visit https://www.file-extensions.org/trx-file-extension-passolo-translation-file).
  • .ts: A .ts file is a Typescript file is an addition to JavaScript that adds static typing. TypeScript code converts to JavaScript, which runs anywhere JavaScript runs (for more information on .ts files and software, please visit https://www.typescriptlang.org/).
  • .tsv: A .tsv file is a very simple textual data format which allows tabular data to be exchanged between applications that use different internal data formats. These files can be opened using open-source programs such as Notepad or other open source, tabular file readers. These files are also known as .tab files (for more information on .tsv files, please visit https://www.file-extensions.org/tsv-file-extension).
  • .tsx: A .tsx file is a TypeScript file similar to .ts files that allow for the writing of elements into JavasScript. These elements closely resemble HTML elements. These files allow the embedding of JSX elements into JavaScript files (for more information on .tsx files and software, please visit https://www.typescriptlang.org/docs/handbook/jsx.html).
  • .txt: The .txt file type is a common text file, which can be opened with a basic text editor. The most common software used to open .txt files are Microsoft Windows Notepad, Sublime Text, Atom, and TextEdit (for more information on .txt files and software, please visit https://www.file-extensions.org/txt-file-extension).

U

  • Unix Executable file: The Unix Executable files are a set of compiled instructions meant to be read by a computer in binary, rather than a program that can be read by a human user. Unix executables often appear in a file list without any file extension. Users can sometimes "open" an Unix Executable file with a hexeditor, such as UltraEdit, which translates the binary into hexadecimal encoding. The hexeditor may also provide a side-by-side plain text translation of the hexcode. However, most of the time the translation is very imperfect, to illegibility. Users may also try to save a Unix Executable as a .txt version, with similar poor results. 

V

  • VISSIM Software: The following file formats are used by VISSIM software to create traffic flow visual model simulations: ATT, ERR, FRQ, INP0, INPX, KNK, LAYX, LSA, MER, NPC, PUA, QMK, RBC, RSR, SIG, TRC, VAP, and VLZ files. It is the microscopic simulation tool for modelling multimodal traffic flows, and it provides ideal conditions for testing different traffic scenarios in a realistic and highly detailed manner before final implementation (for more information on PTV VISSIM software and the Vision Traffic Suite software package, please visit https://www.file-extensions.org/ptv-vissim-file-extensions).
    • .inpx: The .inpx file extension is associated with the PTV Vissim, a software for Microsoft Windows that allows users to simulating and controlling daily road traffic. The .inpx file stores various data used for internal purposes of the PTV Vissim (for more information on .inpx files and software, please visit https://www.file-extensions.org/inpx-file-extension).
  • .vsdx: The .vsdx file type is a Microsoft Visio drawing saved in OPC/XML format and compressed with ZIP compression (for more information on .vsdx files and software, please visit https://www.file-extensions.org/vsdx-file-extension).

W

X

  • .xlsx: The .xlsx files are Microsoft Excel files, which can be opened with Excel, and other free available spreadsheet software, such as OpenRefine. 
  • .xls: The .xls files are Microsoft Excel files, which can be opened with Excel, and other free available spreadsheet software, such as OpenRefine. 
  • .xml: The .xml file type is commonly used for files written in Extensible Markup Language (XML). XML is a human-readable, machine-understandable, general syntax for describing hierarchical data, applicable to a wide range of applications (for more information on .xml files and software, please visit https://www.file-extensions.org/xml-file-extension).
  • .xrdml: XRDML files are used for storing analytical data collected by external measuring devices. XRDML files store data in XML format. These files can be opened using an open-source software such as notepad (for more information on .xrdml files and software, please visit https://www.file-extensions.org/xrdml-file-extension).
  • .xyz: The XYZ file format is a molecular coordinate file. These files can be accessed by many programs, including the free program Surface-water Modeling System (SMS) Software (for more information on .xyz files and software, please visit https://www.file-extensions.org/xyz-file-extension).

Y

  • .yaml: The file type .yaml is commonly related to YAML Ain't Markup Language and used as one of the two typical suffixes for source files written in this language. A .yaml file is typically used for various configuration files (for more information on .yaml files and software, please visit https://www.file-extensions.org/yaml-file-extension).

Z

  • .zip: The .zip file is a compressed archive created with the various programs supporting ZIP compression. Microsoft Windows supports creating compressed zip files by default. You can create ZIP archives in Windows Explorer by using file context menu and send to → Compressed folder (zip method). This will create .zip file of any selected folder or files in your computer (for more information on .zip files and software, please visit https://www.file-extensions.org/zip-file-extension).

Data Services Team

Jesse Long, Data Curation Librarian, jesse.long@dot.gov,  

https://orcid.org/0000-0002-4962-1380

Peyton Tvrdy, Data Management and Data Curation Fellow, 

peyton.tvrdy.ctr@dot.gov, 

https://orcid.org/0000-0002-9720-4725

Data Services Team at the National Transportation Library