Formula (Main window)

Basic example

Simple calculation can be made by assigning a formula to p (or u and v). Open the two files in the directory “bathymetry”:

1. Primary menu → formulatAndIso, then Secondary menu → p = a - b

2. Primary menu → etopo-37_IBI.nc → topography, then Secondary menu → a → interp

3. Primary menu → gebco_[…].tif → 1, then Secondary menu → b → interp

Native functions and variables

Some functions are already coded, the calculation of the slope can be with the two following methods:

1. Primary menu → formulatAndIso, then Secondary menu

2. → p = ( gradx(p0)^2 + grady(p0)^2 )^0.5

3. → p = ellipseM( gradx(p0) , grady(p0) )

4. Primary menu → etopo-37_IBI.nc → topography, then Secondary menu → p0 → interp

Operators

Name	Description
+, -, *, /, ^, %	Addition, difference, product, ratio, power, scalar product
<, <=, >, >=, ==, !=	Comparison operator (return 0 or 1)
or	Merge the fields of different variables

Variables

Name	Description
d2r	Degree to radian (π/180)
e	Exponential
nan	Not a number
pi	π
r2d	Radian to degree (180/π)
lat	Latitude over the view
lon	Longitude over the view
p	Variable that displays a gridded field
u	Variable that displays a gridded zonal velocity (quiver)
v	Variable that displays a gridded meridional velocity (quiver)
pcloud	Variable that displays a pixel cloud
landmask	Landmask
pmask	Mask of the plotted variable [ p or (u,v) ]
	If pmask <= 1 then masked;
	If pmask >= 0 unmasked;
	Gradient of white mask between 0-1
p[4445]	Value of the variable p at index 4445
p[4445.3]	Interpolation of the variable at the location between index 4445 and 4446

Functions

Name	Description
abs()	Norm (real or complex)
arg()	Phase lag (complex)
cos()	Cosine
exp()	Exponential
gradx()	Zonal gradient
grady()	Meridian gradient
sin()	Sine
sinh()	Hyperbolic sine
cnes2date()	Convert Julian days since 1950 to date format (e.g., yyyy-mm-dd hh:mm:ss)
date2cnes()	Convert date format (e.g., yyyy-mm-dd hh:mm:ss) to Julian days since 1950
dx()	Zonal difference to the neighbor pixel
dy()	Meridian difference to the neighbor pixel
fliph()	Flip along x-axis
flipv()	Flip along y-axis
nearest()	Interpolate the masked value with the nearest one
geokm(plg)	Cumulative distance along a polygon
ellipseM(X,Y)	Norm of vector or maximum current of ellipse