I am attempting to extract a specific set of data from a netCDF file and then convert said data to a GeoTIFF.
So far I have managed to extract the data I want using netCDF4, all the data in the file are stored as 1d arrays (lat, lon, data I want) and assigning them to a 2d array. The netcdf file that I am working with was subsetted to a specific region. From here however I am at a loss.
I have a slight understanding of how geotiff conversion works via what I have read at these links:
http://adventuresindevelopment.blogspot.co.uk/2008/12/create-geotiff-with-python-and-gdal.html
And here is what I have currently:
import netCDF4
import numpy as np
from osgeo import gdal
from osgeo import osr
#Reading in data from files and extracting said data
ncfile = netCDF4.Dataset("data.nc", 'r')
dataw = ncfile.variables["dataw"][:]
lat = ncfile.variables["Latitude"][:]
long = ncfile.variables["Longitude"][:]
n = len(dataw)
x = np.zeros((n,3), float)
x[:,0] = long[:]
x[:,1] = lat[:]
x[:,2] = dataw[:]
nx = len(long)
ny = len(lat)
xmin, ymin, xmax, ymax = [long.min(), lat.min(), long.max(), lat.max()]
xres = (xmax - xmin) / float(nx)
yres = (ymax - ymin) / float(ny)
geotransform = (xmin, xres, 0, ymax, 0, -yres)
#Creates 1 raster band file
dst_ds = gdal.GetDriverByName('GTiff').Create('myGeoTIFF.tif', ny, nx, 1, gdal.GDT_Float32)
dst_ds.SetGeoTransform(geotransform) # specify coords
srs = osr.SpatialReference() # establish encoding
srs.ImportFromEPSG(3857) # WGS84 lat/long
dst_ds.SetProjection(srs.ExportToWkt()) # export coords to file
dst_ds.GetRasterBand(1).WriteArray(x) # write r-band to the raster
dst_ds.FlushCache() # write to disk
dst_ds = None # save, close
The process of geotiff creation above I have largely sourced from here:
How do I write/create a GeoTIFF RGB image file in python?
I have attempted this based on the understanding that the array I want to write to the raster is a 2d array with 3 columns, 2 of co-ords and 1 of data. My result which I check in snap is a black page with a white line along the LHS.
So my question is as follows:
How can I extract the necessary geotransform data from my netcdf file, adjust the geotransform parameters appropriately and subsequently use the extracted lat long + dataw arrays to write to a geotiff file?
