Making a vertical section plot using CTDFGRID


Variable to Grid

Variables are entered as generic names or as eps# (e.g. eps20)
Sample variables available are:

T Temperature SAL Salinity SIG Sigma-T
OX Oxygen CO Conductivity U U
V V DYN Dynamic Height PT Potential Temp
STH Sigma-Theta FR Freon

Alternatively choose a variable from the list. (The list is taken from the first data file which might not include the desired variable.)

Horizontal Axis

Select the type of horizontal axis:
P = Profile (axis is consecutive sequence number)
A = Distance Along ship track (axis is kilometers)
Z = Zonal (E-W) projection (axis is longitude)
M = Meridional (N-S) projection (axis is latitude)
L = Least-squares fit to ship track

Grid Nodes

CTDFGRID grids profile data to a regular 2-D grid. Specify the number of nodes in horizontal and vertical direction. (Vertical axis is always pressure/depth for profile type data.)

Depth Axis Range

The vertical axis is always pressure/depth for profile type data (CTD, Bottle, etc.). Specify the range of the depth axis for gridding/plotting.
(Default = 0 - 6,500)

FRGID Parameters

Specify parameters for the FRGID subroutine. FGRID was designed and written by Roger B. Lukas (Dept. of Oceanography, Univ. of Hawaii). The following description of the parameters is from the original FRGID documentation:

The parameter controlling the aspect ratio of the interpolation. DEL is defined as dx/dy strictly, but has been made a parameter to allow the user to exercise more control over the interpolation.
The parameter controlling how much of the fourth order part of the differential equation is to be used in the interpolation.
The maximum distance in grid points which will be used to search for valid data as a first estimate to the solution.

Plot Type

Type of plot. Options are:
LINE = Plot contour lines only.
AREA = Area-filled contour plot.

Color Map

Specify a colormap (with full pathname) or choose one from the list. A colormap is effective only for an area-filled plot. A colorbar will always be displayed.

Contour Levels

Specify desired contour levels following the style of the Plot Plus command CLEV. Examples:
for contour levels from 0 to 10 in increments of .25, with 2 digits after the decimal in contour label and contour levels from 10 to 20 in increments of 2, with integer contour labels
(0,35,.5,1),dark(0,35,5) for contour levels from 0 to 35 in increments of .5, with 1 digit after the decimal in the contour label, and dark lines from 0 to 35 in increments of 5

Show Data Points

If checked the original data points from the input profiles will be plotted.

Label Profiles with Cast Number

If checked the input profiles will be labelled with their cast number.