|Title||Body||Technical Expertise Required||Cost||Additional Information|
|Assign descriptive file names|
File names should reflect the contents of the file and include enough information to uniquely identify the data file. File names may contain information such as project acronym, study title, location, investigator, year(s) of study, data type, version number, and file type.
When choosing a file name, check for any database management limitations on file name length and use of special characters. Also, in general, lower-case names are less software and platform dependent. Avoid using spaces and special characters in file names, directory paths and field names. Automated processing, URLs and other systems often use spaces and special characters for parsing text string. Instead, consider using underscore ( _ ) or dashes ( - ) to separate meaningful parts of file names. Avoid $ % ^ & # | : and similar.
If versioning is desired a date string within the file name is recommended to indicate the version.
Avoid using file names such as mydata.dat or 1998.dat.
|Choose and use standard terminology to enable discovery|
Terms and phrases that are used to represent categorical data values or for creating content in metadata records should reflect appropriate and accepted vocabularies in your community or institution. Methods used to identify and select the proper terminology include:
|Confirm a match between data and their description in metadata|
To assure that metadata correctly describes what is actually in a data file, visual inspection or analysis should be done by someone not otherwise familiar with the data and its format. This will assure that the metadata is sufficient to describe the data. For example, statistical software can be used to summarize data contents to make sure that data types, ranges and, for categorical data, values found, are as described in the documentation/metadata.
|Create a data dictionary|
A data dictionary provides a detailed description for each element or variable in your dataset and data model. Data dictionaries are used to document important and useful information such as a descriptive name, the data type, allowed values, units, and text description. A data dictionary provides a concise guide to understanding and using the data.
|Define the data model|
A data model documents and organizes data, how it is stored and accessed, and the relationships among different types of data. The model may be abstract or concrete.
Use these guidelines to create a data model:
|Define the parameters|
The parameters reported in the data set need to have names that clearly describe the contents. Ideally, the names should be standardized across files, data sets, and projects, in order that others can readily use the information.
The documentation should contain a full description of the parameter, including the parameter name, how it was measured, the units, and the abbreviation used in the data file.
A missing value code should also be defined. Use the same notation for each missing value in the data set. Use an extreme value (-9999) and do not use character codes in a numeric field. Supply a flag or a tag in a separate field to define briefly the reason for the missing data.
Within the data file use commonly accepted abbreviations for parameter names, for example, Temp for temperature, Precip for precipitation, Lat and Long for latitude and longitude. See the references in the Bibliography for additional examples. Some systems still have length limitations for column names (e.g.13 characters in ArcGIS); lower case column names are generally more transferrable between systems; Space and special characters should not be used in attribute names. Only numbers, letters and underscors (“_”) transfer easily between systems.
Also, be sure to use consistent capitalization (not temp, Temp, and TEMP in the same file).
|Describe format for spatial location|
Spatial coordinates should be reported in decimal degrees format to at least 4 (preferably 5 or 6) significant digits past the decimal point. An accuracy of 1.11 meters at the equator is represented by +/- 0.00001. This does not include uncertainty introduced by a GPS instrument.
Provide latitude and longitude with south latitude and west longitude recorded as negative values, e.g., 80 30' 00" W longitude is -80.5000.
Make sure that all location information in a file uses the same coordinate system, including coordinate type, datum, and spheroid. Document all three of these characteristics (e.g., Lat/Long decimal degrees, NAD83 (North American Datum of 1983), WGRS84 (World Geographic Reference System of 1984)). Mixing coordinate systems [e.g., NAD83 and NAD27 (North American Datum of 1927)] will cause errors in any geographic analysis of the data.
If locating field sites is more convenient using the Universal Transverse Mercator (UTM) coordinate system, be sure to record the datum and UTM zone (e.g., NAD83 and Zone 15N), and the easting and northing coordinate pair in meters, to ensure that UTM coordinates can be converted to latitude and longitude.
To assure the quality of the geospatial data, plot the locations on a map and visually check the location.
|Describe formats for date and time|
For date, always include four digit year and use numbers for months. For example, the date format yyyy-mm-dd would appear as 2011-03-15 (March 15, 2011).
If Julian day is used, make sure the year field is also supplied. For example, mmm.yyyy would appear as 122.2011, where mmm is the Julian day.
If the date is not completely known (e.g. day not known) separate the columns into parts that do exist (e.g. separate column for year and month). Don't introduce a day because the database date format requires it.
For time, use 24-hour notation (13:30 hrs instead of 1:30 p.m. and 04:30 instead of 4:30 a.m.). Report in both local time and Coordinated Universal Time (UTC). Include local time zone in a separate field. As appropriate, both the begin time and end time should be reported in both local and UTC time. Because UTC and local time may be on different days, we suggest that dates be given for each time reported.
Be consistent in date and time formats within one data set.
|Describe method to create derived data products|
When describing the process for creating derived data products, the following information should be included in the data documentation or the companion metadata file:
|Describe the contents of data files|
A description of the contents of the data file should contain the following: