trying to download data using Pydap - according to https://wiki.earthdata.nasa.gov/display/EL/How+To+Access+Data+With+PyDAP

getSampleDataFromNASAopenDODS.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

###################
# Author: Mateusz Kędzior
# Downloads sample data from NASA GSFC server
# just execute getSampleData()
###################
# Prerequisities:
# -----1---------
# Create your account and approve 'NASA GESDISC DATA ARCHIVE' application as described at:
# http://disc.sci.gsfc.nasa.gov/registration/authorizing-gesdisc-data-access-in-earthdata_login
# -----2---------
# Create .netrc file - I wrote small gist for that which will be executed to create .netrc file (you will be asked for password)
# -----3---------
# Install Pydap and dependencies
# pip install Pydap numpy singledispatch Webob Jinja2 docopt gunicorn six mechanicalsoup
## or even better create virtual env for pydap:
## sudo apt-get install virtualenv
## virtualenv pydap
## source pydap/bin/acitvate
## pip install pydap
# -----4---------
# Ensure that you have the latest pip modules installed
# (sample error: no cas.urs module):
## pip install --upgrade pip
## pip freeze --local | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 pip install -U


# Samples from: https://wiki.earthdata.nasa.gov/display/EL/How+To+Access+Data+With+PyDAP
# are **outdated**
# Proper samples could be found at: http://www.pydap.org/en/latest/client.html#urs-nasa-earthdata
########################
# Create .netrc login file needed to log in
import requests
url = "https://gist.githubusercontent.com/kedziorm/3f6634f0231ad3b743461519a47d7c9b/raw"
r = requests.get(url).text
exec(r)
########################
# Read login and password from .netrc file
import netrc

authData = netrc.netrc().hosts['urs.earthdata.nasa.gov']
myLogin = authData[0]
myPassword = authData[2]
########################

import cookielib
import urllib2
import re, uuid

import pydap.lib
from pydap.exceptions import ClientError
import logging

log = logging.getLogger("__main__")###(__name__)
log.setLevel(logging.DEBUG)

from os.path import expanduser
import subprocess,os.path
home = expanduser("~")
plik = os.path.join(home,  str(uuid.uuid4().get_hex())  + '.tif')

# Set the debug level for urllib2.
debuglevel=1

def createRasterFile(lon, lat, array, outputFile = 'myraster.tif', noData = -9.99000000e+08, myFormat='GTiff'):
    # Saves numpy.ndarray to GDAL file
    # Sample formats: GTiff (GeoTIFF)
    # (AAIGrid (ASCII GRID) not supported!!)
    import numpy as np
    from osgeo import gdal
    from osgeo import gdal_array
    from osgeo import osr

    # Remove single-dimensional entries 
    # for example change matrix of following dimenstions: (1,1,24,34) to (24,34)
    array = np.squeeze(array)
    # set NoData Values - I think that it is better to set in different way
    # so commenting following line and do that by SetNoDataValue
    # array[array==noData] = np.nan
    xmin,ymin,xmax,ymax = [lon.min(),lat.min(),lon.max(),lat.max()]
    nrows,ncols = np.shape(array)
    xres = (xmax-xmin)/float(ncols)
    yres = (ymax-ymin)/float(nrows)
    geotransform=(xmin,xres,0,ymax,0, -yres)

    print "xmin,ymin,xmax,ymax are: %d, %d, %d, %d" % (xmin,ymin,xmax,ymax)
    print "Saving '%s'" % outputFile

    output_raster = gdal.GetDriverByName(myFormat).Create(outputFile,ncols, nrows, 1 ,gdal.GDT_Float32)  # Open the file
    output_raster.SetGeoTransform(geotransform)  # Specify its coordinates
    output_raster.GetRasterBand(1).SetNoDataValue(noData)
    srs = osr.SpatialReference()                 # Establish its coordinate encoding
    srs.ImportFromEPSG(4326)                     # This one specifies WGS84 lat long.
    output_raster.SetProjection( srs.ExportToWkt() )
    output_raster.GetRasterBand(1).WriteArray(array)

def tif2ASCII(inFile):
    import os
    newFile = os.path.splitext(inFile)[0]+'.asc'
    os.system('gdal_translate -of AAIGrid "%s" "%s"' % (inFile, newFile))

def tif2XYZ(inFile):
    # TODO: Something wrong with NA (noData) value
    import os
    newFile = os.path.splitext(inFile)[0]+'.txt'
    os.system('gdal2xyz.py "%s" "%s"' % (inFile, newFile))

def getSampleData():
    global myLogin
    global myPassword
    import urllib,sys
    modules = ("Pydap", "numpy", "singledispatch", "Webob", "Jinja2", "docopt", "gunicorn", "six", "mechanicalsoup")
    if not ('pydap' in sys.modules):
        print("Please install Pydap and all required modules:")
        print(modules)
        return
    
    #  In case of previous query, I received and 'Exception: Unable to parse token: <!DOCTYPE'
    #  and dds had following content:
    #
    #	<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
    #	<html><head>
    #	<title>301 Moved Permanently</title>
    #	</head><body>
    #	<h1>Moved Permanently</h1>
    #	<p>The document has moved <a href="https://hydro1.gesdisc.eosdis.nasa.gov/dods/_expr_{GLDAS_NOAH025SUBP_3H}{ave(rainf,time=00Z29Sep2016,time=00Z30Sep2016)}{17.00:25.25,48.75:54.50,1:1,00Z29Sep2016:00Z29Sep2016}.ascii.dds?result">here</a>.</p>
    #	</body></html>
    #
    # old_query = 'http://hydro1.sci.gsfc.nasa.gov/dods/_expr_%7BGLDAS_NOAH025SUBP_3H%7D%7Bave(rainf,time=00Z29Sep2016,time=00Z30Sep2016)%7D%7B17.00:25.25,48.75:54.50,1:1,00Z29Sep2016:00Z29Sep2016%7D.ascii?result'
    #
    sample_query = 'https://hydro1.gesdisc.eosdis.nasa.gov/dods/_expr_{GLDAS_NOAH025SUBP_3H}{ave(rainf,time=00Z29Sep2016,time=00Z30Sep2016)}{17.00:25.25,48.75:54.50,1:1,00Z29Sep2016:00Z29Sep2016}.ascii.dds?result'
    #
    # As a result of changing query, now I'm receiving different error:
    # ValueError: need more than 1 value to unpack
    #


    from pydap.client import open_url
    from pydap.cas.urs import setup_session
    session = setup_session(myLogin, myPassword)
    
    dataset = open_url(sample_query, session=session)
    # Following line prints on the screen:
    # <BaseType with data BaseProxy('https://hydro1.gesdisc.eosdis.nasa.gov/dods/_expr_{GLDAS_NOAH025SUBP_3H}{ave(rainf,time=00Z29Sep2016,time=00Z30Sep2016)}{17.00:25.25,48.75:54.50,1:1,00Z29Sep2016:00Z29Sep2016}.ascii.dds', 'result.result', dtype('>f4'), (1, 1, 24, 34), (slice(0, 1, 1), slice(0, 1, 1), slice(0, 24, 1), slice(0, 34, 1)))>
    print(dataset.result.result)
    # Following line causing ValueError: need more than 1 value to unpack

    array = dataset.result.result[:]
    # Line above cause:
    # ValueError                                Traceback (most recent call last)
    # <ipython-input-12-fca8c5905553> in <module>()
    # ----> 1 getSampleData()

    # <ipython-input-11-ff09df6f7236> in getSampleData()
    #     144     dataset = open_url(sample_query, session=session)
    #     145     print(dataset.result.result)
    # --> 146     array = dataset.result.result[:]
    #     147     array_dim = array.shape
    #     148     lat = dataset.result.lat[:]

    # /usr/local/lib/python2.7/dist-packages/pydap/model.pyc in __getitem__(self, index)
    #     256             return np.vectorize(decode_np_strings)(self.data[index])
    #     257         else:
    # --> 258             return self.data[index]
    #     259 
    #     260     def __len__(self):

    # /usr/local/lib/python2.7/dist-packages/pydap/handlers/dap.pyc in __getitem__(self, index)
    #     129         r = GET(url, self.application, self.session)
    #     130         raise_for_status(r)
    # --> 131         dds, data = r.body.split(b'\nData:\n', 1)
    #     132         dds = dds.decode(r.content_encoding or 'ascii')
    #     133 

    # ValueError: need more than 1 value to unpack

    array_dim = array.shape
    lat = dataset.result.lat[:]
    lon = dataset.result.lon[:]

    createRasterFile(lon,lat,array,plik)
    tif2ASCII(plik)
    tif2XYZ(plik)

Hello @kedziorm!

Did you work manage to work a way around this?

I am trying to get some NASA data via pyDAP and getting the exact same error.

Thanks,

Tomas