Satellite Data > Satellite FAQ > Question

Question

How do I read the GOES Imager data provided by CLASS?

Answer

The GOES data provided by CLASS comes in a few formats: The satellite format converter developed at NCDC will convert CLASS-netCDF and Area files to netCDF format (applying a calibration and navigation as needed).

The weather and climate toolkit developed at NCDC will calibrate and remap CLASS-Area files to various output formats, some of which can be used with GIS software.

Image Formats: GIF/JPG

This format is primarily for qualitative use of the data. Data provided in image formats (GIF, JPG) can generally be read by numerous software applications.

netCDF

This data is primarily for quantitative use of the data. NetCDF data can be read using various applications. See the netCDF website for more information on using the netCDF library to read netCDF files. For your reference sample output from the ncdump utility on a netCDF file provided by CLASS is provided:
ncdump -h goes12.2004.306.173144.BAND_02.L4076651

Area

This data is primarily for quantitative use of the data. Although the Area format is a McIDAS format, the files can be read using other software.
McIDAS (Man Computer Interactive Data Access System)
Area files can be directly read, navigated and calibrated using the McIDAS software. Also, see the McIDAS Users' Group web site for more details.
Fortran
Fortran code can be made available for reading Area files from NCDC. The code is compiled on a linux system using Lahey-Fujitsu Fortran 95 compiler (lf95) version 6.20d. However, the current version uses compiler-specific functions (lstat) to perform the read. Contact the NCDC.Satorder@noaa.gov if you think this may be the best option for you.
IDL
Scientists at NCDC have made their read routines available for IDL users. The routines read Area files provided by CLASS (an example is provided which can be used with the sample data). Routines and data are available as a gzipped tar file.
Other tools
Other tools are available for displaying GOES McIDAS area files. These include: Format Description Documents
If you are interested in developing your own Area format reader (or your required programming language is not listed above) the area format is described by the McIDAS Users' Group.
  • The new format describes Area files, including the GVAR Area files.
  • An older Area format is also described, which includes the GOES formats for GOES-4-7.
  • More details (such as details on the line prefix documentation) of the AREA format are also available here.

Raw

Imagery in the "Raw" format is in the raw data format received by the data provider. For GOES-Imager data, this format is GVAR (GOES VARiable). The vast majority of users will not need GVAR data format. Users of imagery should order image formats (mentioned above) and others interested in using the data quantitatively should make use of the Area format options. The GVAR format is summarized in NOAA Technical Report NESDIS 82. At present, there are no known, publicly-available GVAR readers.