File Format Guide

The following file formats are supported as data distribution formats within the Data Discovery Center. Within the DDC, most tabular data are distributed as CSV files, while most raster and imagery data are distributed as GeoTiff files. Other selected data formats used within the DDC include HDF, JPG, MP3, MP4, and NetCDF.



A CSV (Comma Separated Value or Character Separated Value) file format is an ASCII text tabular file format consisting of rows and columns separated by delineators. Records are delineated by lines and columns by commas or other delineating characters. The file extension for a CSV file is .csv. CSV files can be imported into most commercial and open source data processing applications.


A, B, C, D, E, F, G, H, I, J, K, L, M
1, 1, 3, 3, 9, 0, 4, 2, 7, 8, 1, 8, 0
8, 3, 4, 5, 8, 2, 0, 0, 3, 4, 5, 6, 8
3, 4, 4, 3, 5, 7, 5, 7, 5, 9, 0, 0, 2

GeoTiff (Tiff: Tagged-Image File Format) is a platform-independent standard that supports geographically referenced raster data layers, satellite imagery, aerial photos, and digital elevation models (DEMs). Spatial reference information for a GeoTiff is encapsulated within embedded tags within the file. GeoTiff files can be imported into most commercial and open sources image visualization programs as a standard Tiff image, but can also be used within geospatial applications such as ArcGIS, and ERDAS Imagine, or IDL ENVI. The file extension for a GeoTiff is .tif.

HDF (Hierarchical Data Format) is a self-describing, binary format originally created at the NCSA (National Center for Supercomputing Applications for use in storing massive amounts of data. HDF files can be accessed via C, C++, Fortran, Fortran 90, CLI - .Net. and Java APIs and IDL, MATLAB, Python, and R third party bindings. The file extension for an HDF file is .hdf.
JPG is a file extension for lossy (compressed) digital images. The degree of compression is variable, however, there is a trade-off between image quality and file size. JPEG stands for Joint Photographic Experts Group, the group that created the standard. The JPEG file extension is used interchangeably with JPG. 
MP3 is a common audio format used in audio streaming and storage. MP3 uses a form of lossy data compression that results in smaller files sizes that can be easily shared over the Internet. The file extension for an MP3 file is .mp3.
MP4 is a file format created by the Moving Picture Experts Group (MPEG) as a multimedia format for storing audiovisual data. MP4 files are supported by most software media players as well as many Blu-ray/DVD players. The file extension for an MP4 file is .mp4.
NetCDF (Network Common Data Form) is a self-describing, binary format for the creation, query, and distribution of scientific data stored as arrays. The NetCDF format was developed by the UNIDATA program at the University Corporation for Atmospheric Research (UCAR). NetCDF files can be read and viewed by a variety of software applications including ncView and ArcGIS. The file extension for NetCDF files is .ncf
For additional information and a list of tools available for NetCDF files please visit: unidata: NetCDF Information and/or unidata: Software for use with NetCDF