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CSV Standards

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General Formatting

  • Use ".csv" as the file extension
  • File names in snake case; i.e., lowercase with underscores like "example_file_name.csv" instead of spaces
  • Single header row with descriptive column names
  • Include one column that can be used as the unique identifier; the data type of that column can be either text or number
  • Do not include URLs in the data file
  • Columns delimited by commas
  • No empty lines or rows
  • Each row should have the same number of columns

Spatial Data

  • Latitude and longitude in separate columns with names "latitude" and "longitude" or "lat" and "lon"
  • Latitude and longitude given as decimal degrees
  • If a data file is not based on WGS 84 geographic coordinate system (e.g., EPSG:4326), use CoordX and CoordY as the column names
  • An optional *.prj file can be used to explicitly specify the projected coordinate system

Variables and Values

  • Column names in snake case; i.e., lowercase with underscores like "example_column_name" instead of spaces
  • Missing data for numeric columns coded as "-9999" and uses the appropriate level of precision
  • Missing data for text columns coded as "NA"
  • If a text field includes commas and quotes, save the file with the option of placing quotes around all text fields
  • Dates and times in 24 hour UTC; use local time zones only in addition to UTC
  • Dates in YYYY-MM-DD format
  • Times in hh:mm:ss format (or hh:mm:ss+nn if a time zone needs to be included)
  • Named sites and locations should have an associated geographic location
  • Columns should contain only text values or only numeric values, not a mixture of both. While many tools (such as Excel) will let you mix text values and numeric values in a single column, such as in the example below, this makes the data much more difficult to work with.

    The following is an example of what you should not do -- mixing numeric and text values in a single column:

    estimated_depth shrub_cover
    4 30
    6 > 75
    4 to 5 25
    5 65

See Best Practices for Data Management for additional guidance.