NRAO VLA Image Archive query

astroquery/nrao/__init__.py

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+from .nrao_image_archive import *

astroquery/nrao/nrao_image_archive.py

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+
+"""
+NRAO Image Archive Query Tool
+-----------------------------------
+
+:Author: Adam Ginsburg (adam.g.ginsburg@gmail.com)
+"""
+import urllib2
+import urllib
+import os
+import sys
+import astropy.io.fits as pyfits
+from math import cos, radians
+import multiprocessing as mp
+import time
+import tempfile
+import StringIO
+from astroquery.utils import progressbar
+import coords
+import htmllib
+import formatter
+import re
+
+imfits_re = re.compile("http://[^\"]*\\.imfits")
+uvfits_re = re.compile("http://[^\"]*\\.uvfits")
+config_re = re.compile("([ABCD]/[ABCD]) configuration")
+
+request_URL = "https://webtest.aoc.nrao.edu/cgi-bin/lsjouwer/archive-pos.pl"
+
+__all__ = ['get_nrao_image']
+
+
+valid_bands = ["","L","C","X","U","K","Q"]
+
+band_freqs = {
+    "L":	(1,2),
+    "S":	(2,4),
+    "C":	(4,8),
+    "X":	(8,12),
+    "U":	(12,18),
+    "K":	(18,26.5),
+    "Ka":	(26.5,40),
+    "Q":	(30,50),
+    "V":	(50,75),
+    "E":	(60,90),
+    "W":	(75,110),
+    "F":	(90,140),
+    "D":	(110,170),
+    }
+
+
+def get_nrao_image(lon, lat, system='galactic', epoch='J2000', size=1.0,
+        max_rms=1e4, band="", verbose=True, savename=None, save=True,
+        overwrite=False, directory='./', get_uvfits=False):
+    """
+    Search for and download
+
+    Parameters
+    ----------
+    lon : float
+    lat : float
+        Right ascension and declination or glon/glat
+    system : ['celestial','galactic']
+        System of lon/lat.  Can be any valid coordinate system supported by the
+        coords package
+    epoch : string
+        Epoch of the coordinate system (e.g., B1950, J2000)
+    savename : None or string
+        filename to save fits file as.  If None, will become G###.###p###.###_(survey).fits
+    size : float
+        Size of search radius (arcminutes)
+    max_rms : float
+        Maximum allowable noise level in the image (mJy)
+    verbose : bool
+        Print out extra error messages?
+    save : bool
+        Save FITS file?
+    overwrite : bool
+        Overwrite if file already exists?
+    directory : string
+        Directory to store file in.  Defaults to './'.  
+    get_uvfits : bool
+        Get the UVfits files instead of the IMfits files?
+
+    Examples
+    --------
+    >>> fitsfile = get_nrao_image(49.489,-0.37)
+    """
+
+    if band not in valid_bands:
+        raise ValueError("Invalid band.  Valid bands are: %s" % valid_bands)
+
+    ra,dec = coords.Position([lon,lat],system=system,equinox=epoch).j2000()
+    radecstr = coords.Position([ra,dec],system='celestial',equinox='J2000').hmsdms().replace(":"," ")
+    glon,glat = coords.Position([ra,dec],system='celestial',equinox='J2000').galactic()
+
+    # Construct request
+    request = {}
+    request["nvas_pos"] = radecstr
+    request["nvas_rad"] = size
+    request["nvas_rms"] = max_rms
+    request["nvas_scl"] = size
+    request["submit"] = "Search"
+    request["nvas_bnd"] = band
+
+    # create the request header data
+    request = urllib.urlencode(request)
+    # load the URL as text
+    U = urllib.urlopen(request_URL, request)
+    # read results with progressbar
+    results = progressbar.chunk_read(U, report_hook=progressbar.chunk_report)
+
+    if get_uvfits:
+        links = uvfits_re.findall(results)
+    else:
+        links = imfits_re.findall(results)
+    configurations = config_re.findall(results)
+
+    if len(links) == 0:
+        if verbose:
+            print "No matches found at ra,dec = %s." % (radecstr)
+        return []
+
+    if verbose > 1:
+        print "Configurations: "
+        print "\n".join(["%40s: %20s" % (L,C) for L,C in zip(links,configurations)])
+
+    if save and not os.path.exists(directory):
+        os.mkdir(directory)
+    if save:
+        opener = urllib2.build_opener()
+
+    if verbose:
+        print "Found %i imfits files" % len(links)
+
+    images = []
+
+    for link,config in zip(links,configurations):
+
+        # Get image filename
+        basename = os.path.basename(link)
+
+        # Get the file
+        U = opener.open(link)
+        if verbose:
+            print "Downloading image from %s" % link
+            results = progressbar.chunk_read(U, report_hook=progressbar.chunk_report)
+        else:
+            results = U.read()
+        S = StringIO.StringIO(results)
+        try: 
+            fitsfile = pyfits.open(S,ignore_missing_end=True)
+        except IOError:
+            S.seek(0)
+            G = gzip.GzipFile(fileobj=S)
+            fitsfile = pyfits.open(G,ignore_missing_end=True)
+
+        # Get Multiframe ID from the header
+        images.append(fitsfile)
+
+        if save:
+            h0 = fitsfile[0].header
+            freq_ghz = h0['CRVAL3'] / 1e9
+            for bn, bandlimits in band_freqs.iteritems():
+                if freq_ghz < bandlimits[1] and freq_ghz > bandlimits[0]:
+                    bandname = bn
+            obj = str(h0['OBJECT']).strip()
+            program = h0['OBSERVER'].strip()
+            h0['CONFIG'] = config
+
+            if savename is None:
+                if get_uvfits:
+                    filename = "VLA_%s_G%07.3f%+08.3f_%s_%s.uvfits" % (bandname,glon,glat,obj,program)
+                else:
+                    filename = "VLA_%s_G%07.3f%+08.3f_%s_%s.fits" % (bandname,glon,glat,obj,program)
+            else:
+                filename = savename
+
+            # Set final directory and file names
+            final_file = directory + '/' + filename
+
+            if verbose:
+                print "Saving file %s" % final_file
+
+            fitsfile.writeto(final_file, clobber=overwrite)
+
+    return images
+
+

docs/astroquery/nrao.rst

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+.. _astroquery.nrao:
+
+*****************************************
+NRAO Queries (`astroquery.nrao`)
+*****************************************
+
+Getting started
+===============
+
+The following example illustrates an NRAO VLA archive image query::
+
+    >>> from astroquery import nrao
+    >>> fitsfiles = nrao.get_nrao_image(10.5,0.0)
+
+fitsfiles will be a list of FITS HDUs downloaded from the archive.  You can
+specify a band and you can query in other coordinates; the default is galactic.
+
+
+Reference/API
+=============
+
+.. automodapi:: astroquery.nrao
+    :no-inheritance-diagram: