3 tables summarising the nine NASA Ames Format styles and displaying all possible file headers.
Excel templates of FFIs 1001 and 1020
Including examples and instructions on Excel to NASA Ames conversion.
Very well suited to field campaigns involving several teams that need to share their observations, the NASA Ames Format is not well adapted to very voluminous datasets. In this case, although less portable, a binary format is recommended.
|up to four independent variables (usually but not necessarily time and/or space) in most cases, real numbers, one FFI allowing the use of one alphanumeric independent variable (i.e. a piece of text);|
|the primary dependent variables (functions of the former) real numbers;|
|the auxiliary dependent variables (depending solely on the unbounded independent variable) real numbers or character strings.|
The underlying philosophy is that data are stored in a file-based system, a dataset being formed out of a series of numbered files. Typically, files belonging to a same dataset share some common feature such as the people who issued the data, the experiment, the platform,... This, however, is not a requirement and it is up to the data provider to organise the data files into datasets (possibilities ranging from one single dataset including all files to one file per dataset). The number of files of the dataset and the number of the file within the data set are two elements of information that appear in the file header.
Whilst the first definitions of NASA Ames Format included rules regarding file
names, these have been dropped from most recent versions, that now allow any
naming convention or no convention at all.
File names and their extensions may of course include elements of information
on the data (e.g. site name, date, etc) or provide a way to
sort them out.
File name rules have been set up for specific NERC thematic programmes Polluted Troposphere, UFAM, ACSOE, SOAPEX, UTLS-Ozone, URGENT.
|Header or Metadata section
The header includes, in a defined order and format, all the information needed to read and understand the data. Namely:
The data proper are subdivided in a hierarchy of two-dimensional blocks, the last independent variable (which is always the unbounded variable see NASA Ames Format: for which type of data? above) being the most slowly varying one. Note that error margins can be supplied as either primary or auxiliary variables, if needed.
|NASA Ames FFI Summary is a straightforward instrument to identify the appropriate file format index and to format your data step by step. For each FFI, it includes links to detailed descriptions of the corresponding data and metadata formats.|
|Makeheader.f is a self-explanatory Fortran program that generates NASA Ames file headers tailored to the user's needs. It does not require any knowledge of Fortran, only a Fortran compiler.|
|Many data files contain the variable time which can be expressed in several ways. Guidelines on the recommended format of the time-variable header lines, units and the data values are available.|
|The Excel templates of FFIs 1001 and 1020 (Excel format) also include instructions on inserting metadata in NASA Ames files and converting Excel spreadsheets to NASA Ames compliant ASCII files. Two examples of spreadsheets are given for each FFI. Their ASCII versions can be viewed here:|
|Dummies Guide to NASA Ames format with 1D data|
|Dummies Guide to NASA Ames format with 2D data|
|Specific additional rules apply to some NERC thematic programmes (ACSOE, SOAPEX, UTLS-Ozone, URGENT, NEU). Please refer to the Web pages of these data sets.|
|Every File Format Index is explained line by line in the NASA Ames FFI Summary provided by BADC.|
|See also the source manual Gaines and Hipskind, 1998.|