DATA SET DOCUMENTATION (i.e., "Readme" file)



The documentation (i.e., the "Readme" file) that accompanies each project data set is as important as the data itself. This information permits collaborators and other analysts to become aware of the data and to understand any limitations or special characteristics of data that may impact its use elsewhere. The data set documentation should accompany all data set submissions and contain the information listed in the outline below. While it will not be appropriate for each and every data set to have information in each documentation category, the following outline (and content) should be adhered to as closely as possible to make the documentation consistent across all data sets. It is also recommended that a documentation file submission accompany for each preliminary and final data set.



TITLE: This should match the data set name

AUTHOR(S):

1.0 DATA SET OVERVIEW:

2.0 INSTRUMENT DESCRIPTION:

3.0 DATA COLLECTION AND PROCESSING:

4.0 DATA FORMAT:

5.0 DATA REMARKS:

6.0 REFERENCES:



DATA SET CONTENT GUIDELINES

An inherent flexibility of the EOL/CDS data management system permits data in all different formats to be submitted, stored and retrieved from CODIAC. The following data format guidelines are intended to help standardize the information provided with any data archived for the project. These guidelines are based on EOL/CDS experience in handling thousands of different data files of differing formats. Specific suggestions are provided for naming a data file as well as information and layout of the header records and data records contained in each file. This information is important when data are shared with other project participants to minimize confusion and aid in the analysis. An example of the layout of an ASCII file using the guidelines is provided below. Keep in mind that it is not mandatory that the data be received in this format. However, if the project participants are willing to implement the data format guidelines described below, there are some improved capabilities for integration, extraction, compositing and display via CODIAC that are available.

A) Naming convention - all data files should be uniquely named and include an extension indicating the type of file such as:

B) For Text (ASCII) files, the records should consist of both header records and data records. The header records at a minimum should consist of:

ASCII DATA HEADER RECORDS SPECIFICATIONS

Standard header records should precede the data records within the file itself. The header records should contain the following information:

PI/DATA CONTACT = Text [PI and data contact name(s) and affiliation(s)]
DATA COVERAGE = Start/Stop time of continuous data or sampling interval (See format for time in Data Records below)
PLATFORM/SITE = Text [e.g., C130, BROWN, etc.]
INSTRUMENT = Text [instrument name]
COORDINATES = Fixed site coordinates (decimal degrees) or "mobile" (Text)
DATA VERSION = Alphanumeric [unique ID (i.e., revision date), preliminary or final]
REMARKS = Text [PI remarks that aid in understanding data file structure and contents. Items such as file type, how missing and/or bad data are denoted]

------------------------------------------------------------

NOTE - Other information that should be contained in the REMARKS section (if applicable):

Missing Value indicator - Text or integer [value used for data for missing information] (e.g., -99 or 999.99, etc)

Instrument limitations/accuracy:

Below Measurement Threshold - Text or Integer [Value used to signify reading below instrument detection threshold] (e.g., <0.00005)

Above Measurement Threshold - Text or Integer [Value used to signify reading above instrument saturation]

**NOTE** This type of header information cannot be contained within GIF and Postscript files. They will need to be submitted with attached files or separate documentation containing this information.

ASCII DATA RECORDS SPECIFICATIONS:

  1. First data record consists of parameters identifying each column.
  2. Second data record consists of respective parameter units.
  3. Third data record begins actual data and consists of a date/time column followed by position coordinates (if mobile) and subsequent observations at that time and position.

SAMPLE DATA SET (ASCII FORMAT):

The following is an example of an ASCII format data set in which the header precedes the reported data, and the data is organized in columns separated by spaces. Each column is identified by parameter and each parameter's units of measure are listed in the respective column. Also each row has a date/time of observation reported in Universal Time Coordinated (UTC) along with position coordinates. This data set organization is ideal for plotting and integration of various data sets. This data set format should be used whenever possible and could be easily produced automatically from a spread sheet computer program.

------------------------------------------------------------------------------------------------------------

PI/DATA CONTACT= Doe, John (U of Hawaii)/ Doe, Jane (NCAR)
DATA COVERAGE = START: 0421133500; STOP: 0421135500 UTC
PLATFORM/SITE = C130
INSTRUMENT = C-130 External Sampler Data
LOCATION = mobile
DATA VERSION = 1.0 (10 July 2001), PRELIMINARY
REMARKS = National Center for Atmospheric Research, ACE-Asia
REMARKS = ppm values are mole fraction
REMARKS= nM/m3 at 25c and 101.3 kPa; DMS and NH4 in Parts per million (PPM)
REMARKS = Missing data = 99.9; Bad data = 88.8
REMARKS = Data point Date/Time provided in UTC
DATE/TIME LAT LONG SAMPLE NO2 CO DMS NH4
UTC Deg Deg NUMBER nM/m3 PPM PPM PPM
20010421133500.00 33.087 125.116 E1.160.1 1000.65 200.67 345.98 2342.980
20010421133510.00 33.090 125.120 E1.160.2 1003.45 200.60 349.76 2353.345

.

.

.

etc.

------------------------------------------------------------------------------------------------------------