User`s guide

ODV HowTo

Figure 6-1: Identification of outliers for a zonal section in the North Atlantic

7 Importing XYZ Data

Irregularly spaced or gridded data for some quantity Z at given X and Y coordinates are

commonly provided in files using three-columns for the X, Y and Z values, respectively.

Examples of such XYZ datasets are (1) maps of a given Z variable (X represents longi-

tude, Y represents latitude), (2) vertical sections (X=along section coordinate, Y=depth)

or (3) time-evolution plots (X=some geographical coordinate, Y=time or vice versa).

You can load all these XYZ files into ODV and you can analyze and display the Z data us-

ing the full suite of ODV functions. Note that the procedures described below can also be

applied to data files with multiple Z variables, e.g., files with more than three columns.

Here is how to proceed if the XYZ file represents a map:

1. Create a new collection (choose a destination directory and collection name)

with just two variables Depth [m] and Z-variable (use a descriptive label and ap-

propriate units for the Z-variable),

2. Import the XYZ file by choosing Import>ODV Spreadsheet and selecting the XYZ

file (note that you have to choose file-type All Files, if the extension of the XYZ file

is not .txt).

3. On the Spreadsheet File Properties dialog specify (1) the column separation char-

acter (the items from the header line should appear on separate lines in the Col-

umn Labels list), (2) the line number containing XYZ labels (keep 1, if no labels

are provided), and (3) the line number of the first data line,

4. On the Metadata Variable Association dialog associate the X-variable with Longi-

tude [degrees_east] and the Y-variable with Latitude [degrees_north],

5. On the Import Options dialog associate the Z-variable (source) with the second

collection variable (target). Then click on the first collection variable (target),