project

project(x, y, fromproj=KnownCoordinateSystems.geographic.world.WGS1984, toproj=KnownCoordinateSystems.geographic.world.WGS1984)

Create a projection object with Proj.4 parameters.

Project geographic coordinates from one projection to another.

Parameters:

• x – (array_like) X coordinate values for projection.
• y – (array_like) Y coordinate values for projection.
• fromproj – (ProjectionInfo) From projection. Default is longlat projection.
• toproj – (ProjectionInfo) To projection. Default is longlat projection.

Returns:

(array_like, array_like) Projected geographic coordinates.

Example:

Project a geographic coordinate from longlat projection to Lambert projection:

>>> fromproj = projinfo()
>>> toproj = projinfo(proj='lcc', lon_0=104.137, lat_0=35.946, lat_1=30.0, lat_2=60.0)
>>> lon = 104.583
>>> lat = 35.5731
>>> x, y = project(lon, lat, fromproj=fromproj, toproj=toproj)
>>> x, y
(39626.10751807479, -40422.11861349553)

Project Lambert coordinates to longlat projection:

#Add file
fn = 'D:/Temp/grads/wrfout_d02.ctl'
f = addfile(fn)
#Get a variable
v = f['T2']
#Get X/Y dimension value - coordinates under Lambert projection
x = v.dimvalue(2)
y = v.dimvalue(1)
#Project X/Y to Lon/Lat
toproj = projinfo()    #Lon/Lat projection
xx, yy = meshgrid(x, y)
lon, lat = project(xx, yy, fromproj=f.proj, toproj=toproj)
#Write lon/lat
lon.savegrid(x, y, 'C:/Temp/test/lon.txt')
lat.savegrid(x, y, 'C:/Temp/test/lat.txt')
#Plot for test
scatter(lon[::4,::4], lat[::4,::4], edge=False, size=3, color='b')