scientimate.windfetch#

wind_fetch, z_mean, z_point, bed_slope_mean, x_fetch, y_fetch, z_fetch, dist_along_fetch = scientimate.windfetch(xgrid, ygrid, zgrid, x_point, y_point, winddir=0, waterlevel=0, shorelinelevel=0, n_midpoints=100, distCalcMethod='gc', interpMethod='nearest', dispout='no')

Description#

Calculate a wind fecth and z (elevation) profile along a path over water for a given 2d x-y domain (map, image, …)

Inputs#

xgrid: x (longitude) data as a [M*N] array
ygrid: y (latitude) data as a [M*N] array
zgrid: z (elevation) data as a [M*N] array

z>=0 is considered land, z<0 is considered water
x_point: x (longitude) of the points to find fetches toward those points

If x data are longitude, they should be in Degree
y_point: y (latitude) of the points to find fetches toward those points

If y data are latitude, they should be in Degree
winddir=0: Meteorological wind direction in (Degree)

It represents a direction wind comes from and is measured counter-clockwise from the North

0 (degree): from North, 90 (degree): from East, 180 (degree): from South, 270 (degree): from West
waterlevel=0: Water surface level (Should have the same datum as zgrid)

Size of waterlevel should be either 1 or should be equal to size of winddir

If water level is zero (waterlevel=0), it means that the water level is at a level of surface elevation (z=0) in bathymetry data

If water surface level is positive (waterlevel>0), it means that the water level is above zero elevation (z=0) in bathymetry data

,therefore water level will be subtracted from bathymetry elevation

If water surface level is negative (waterlevel<0), it means that the water level is below zero elevation (z=0) in bathymetry data

,therefore water level will be added to bathymetry elevation
shorelinelevel=0: Shoreline elevation,

z>=shorelinelevel is considered land, z<shorelinelevel is considered water
n_midpoints=100: Number of middle points generated between first point and last point

if n_midpoints=1 then 1 point between first point and last point is generated
distCalcMethod=’gc’: Distance calculation method

‘cart’: Distances are calculated on cartesian coordinate

‘gc’: Distances are calculated on Great Circle based on Vincenty formula, Vincenty (1975)

Earth radius considered as mean earth radius=6371000 m
interpMethod=’nearest’: Interpolation method

‘linear’: Use default or ‘linear’ method to interpolate

‘nearest’: Use nearest neighbor method to interpolate
dispout=’no’: Define to display outputs or not (‘yes’: display, ‘no’: not display)

Outputs#

wind_fetch: Total wind fecth distance along a path from shoreline to point (x_point,y_point) with angle of winddir

If input data are latitude and longitude in Degree, wind_fetch is in m
z_mean: Mean of z (elevation) along a wind fetch
z_point: Value of z (elevation) at (x_point,y_point) location
bed_slope_mean: Mean of bed slope along a wind fetch
x_fetch: x (longitude) along a path at given points (x_fetch,y_fetch)
y_fetch: x (latitude) along a path at given points (x_fetch,y_fetch)
z_fetch: z (elevation, …) data along a path at given points (x_fetch,y_fetch)
dist_along_fetch: Distance at each points of (x_fetch,y_fetch) from the domain boundary

If input data are latitude and longitude in Degree, dist_along_fetch is in m

Examples#

import scientimate as sm
import numpy as np
import os

xgrid,ygrid=np.meshgrid(np.linspace(-5,5,100),np.linspace(-5,5,100))
R=np.sqrt(xgrid**2+ygrid**2)
zgrid=np.sin(R)/R
x_point=-4
y_point=-2
winddir=90
waterlevel=0
shorelinelevel=0
n_midpoints=100
wind_fetch,z_mean,z_point,bed_slope_mean,x_fetch,y_fetch,z_fetch,dist_along_fetch=sm.windfetch(xgrid,ygrid,zgrid,x_point,y_point,winddir,waterlevel,shorelinelevel,n_midpoints,'cart','nearest','yes')

xgrid,ygrid=np.meshgrid(np.linspace(-5,5,100),np.linspace(-5,5,100))
zgrid=ygrid*np.sin(xgrid)-xgrid*np.cos(ygrid)-3
x_point=0
y_point=0
winddir=np.arange(0,360+30,30)
waterlevel=np.ones(np.size(winddir))*0.1
shorelinelevel=0
n_midpoints=100
wind_fetch,z_mean,z_point,bed_slope_mean,x_fetch,y_fetch,z_fetch,dist_along_fetch=sm.windfetch(xgrid,ygrid,zgrid,x_point,y_point,winddir,waterlevel,shorelinelevel,n_midpoints,'cart','nearest','yes')

#Download Persina Gulf and Gulf of Oman with coordinate exteneds xmin=47, xmax=63, ymin=19, ymax=31 from https://maps.ngdc.noaa.gov/viewers/grid-extract/index.html
xyzfilename='xyz.csv'; #e.g. xyzfilename='PersianGulf.csv'
xyzfilelocation=os.getcwd(); #e.g. xyzfilelocation=r'C:/datafolder'
x,y,z=sm.readxyz(xyzfilename,xyzfilelocation,1,'all');
xgrid,ygrid,zgrid=sm.interpxyz2grid(x,y,z,100,'points',np.nanmin(x),np.nanmax(x),np.nanmin(y),np.nanmax(y),np.nanmin(z),np.nanmax(z),'all','nearest','no');
x_point=58.0 #Or x_point=52.0
y_point=24.5 #Or y_point=26.0
winddir=[0,40,135,280]
waterlevel=0
shorelinelevel=0
n_midpoints=100
wind_fetch,z_mean,z_point,bed_slope_mean,x_fetch,y_fetch,z_fetch,dist_along_fetch=sm.windfetch(xgrid,ygrid,zgrid,x_point,y_point,winddir,waterlevel,shorelinelevel,n_midpoints,'gc','nearest','yes');

References#

Vincenty, T. (1975). Direct and inverse solutions of geodesics on the ellipsoid with application of nested equations. Survey review, 23(176), 88-93.

scientimate.windfetch

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