NetCDF Longitude values shift

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07-02-2018 06:31 AM
anTonialcaraz
Occasional Contributor II

Hi,

I've been several days with this not quite getting what I need. Any help would be much appreciated.

I'm trying to use python to shift the longitude values of a netcdf file. The original file longitude goes from -1.875 to +360

I need the file to show properly when importing it in Arcmap (Make NetCDF Raster Layer) so the raster and its values are -180 180 (as well as -90 90). The values are vertical velocity depth.

I'm trying a short script that someone showed online with a similar issue. Apparently it worked for him. In my case I just manage to shift the frame but not the values (see picture).

global map -180 180 but actual depth values not shifting

Any suggestions? Many thanks

import arcpy
import numpy as np
import netCDF4
from netCDF4 import Dataset
from arcpy import env
arcpy.env.overwriteOutput=True
from arcpy.sa import*
arcpy.CheckOutExtension("Spatial")


Bathy = Dataset(r"H:\NETcdf_TEST\tdhteo.pfclapr.nc",'r+', format="NETCDF4")

lon = Bathy.variables[u'longitude'][:]
lat = Bathy.variables[u'latitude'][:]
depth = Bathy.variables[u'W_mm_dpth'][:]

depth_new = np.roll(depth, 360, axis = 1)
lon_new = lon[:]-178.125

Bathy.variables[u'longitude'][:] = lon_new
Bathy.variables[u'W_mm_dpth'][:] = depth_new
Bathy.close()
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anTonialcaraz
Occasional Contributor II

This does the job. Thanks

depth_new = np.roll(depth, 720, axis = 3)

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anTonialcaraz
Occasional Contributor II

This does the job. Thanks

depth_new = np.roll(depth, 720, axis = 3)
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