Repository: sunpy/sunpy

Issue:
Need a clear tutorial on downloading and viewing data
Although there seem to be some examples/tutorials in the documentation that use the sample data, there are no obvious examples on how to download and then view/analyse non-sample data. The ones I can find are

- http://docs.sunpy.org/en/stable/generated/gallery/acquiring_data/2011_06_07_sampledata_overview.html#sphx-glr-generated-gallery-acquiring-data-2011-06-07-sampledata-overview-py - only has sample data
- http://docs.sunpy.org/en/stable/generated/gallery/acquiring_data/skip_searching_vso.html#sphx-glr-generated-gallery-acquiring-data-skip-searching-vso-py - only shows how to search for data
- http://docs.sunpy.org/en/stable/guide/tour.html#obtaining-data - only shows how to search for data
- http://docs.sunpy.org/en/stable/guide/tour.html#maps only has sample data.

And that's it really... A linked up tutorial on searching for, downloading, and plotting some data, which assumes no previous knowledge of SunPy would be much appreciated.


Discussion:
I think this would be best written into the Guide section of the docs, with plenty of description about why things are done like they are etc. 

Resolving patch:
diff --git a/examples/acquiring_data/downloading_and_plotting.py b/examples/acquiring_data/downloading_and_plotting.py
new file mode 100644
--- /dev/null
+++ b/examples/acquiring_data/downloading_and_plotting.py
@@ -0,0 +1,56 @@
+"""
+======================================
+Downloading and plotting LASCO C3 data
+======================================
+
+In this example, we show how to acquire and plot SOHO/LASCO C3 data using SunPy.
+"""
+# Import the required modules.
+from sunpy.net import Fido, attrs
+import sunpy.map
+from sunpy.io.file_tools import read_file
+
+###############################################################################
+# In order to download the required data, we will use
+# `Fido <sunpy.net.fido_factory.UnifiedDownloaderFactory>`, a downloader client.
+# Using the `Fido.search` method, we need to define two variables:
+# a timerange (`~sunpy.net.attrs.Time`) and
+# a instrument (`~sunpy.net.attrs.Instrument`).
+
+timerange = attrs.Time('1996/05/24 11:00', '1996/05/24 12:00')
+instrument = attrs.Instrument('C3')
+
+###############################################################################
+# This now must be passed in ``Fido.search`` which will query the
+# online services:
+
+result = Fido.search(timerange, instrument)
+
+# ``result`` contains the return from the online search.
+# In this case, we have found 4 files that correspond to our search parameters.
+print(result)
+
+###############################################################################
+# The next step is to download the search results and `Fido.fetch` will be used.
+# We will pass in the ``result`` and ``downloaded_files`` will contain
+# a list of the location of each of the downloaded files.
+
+downloaded_files = Fido.fetch(result)
+print(downloaded_files)
+
+###############################################################################
+# Finally we can pass in the first file we downloaded into `sunpy.map.Map`
+# to create a SunPy Map object which allows us to easily plot the image.
+# However, there is a problem here. The downloaded file lacks the correct meta
+# information needed to create a `sunpy.map.Map`.
+
+# We want to open the file and access both the data and the header information.
+data, header = read_file(downloaded_files[0])[0]
+
+# Add the missing meta information to the header
+header['CUNIT1'] = 'arcsec'
+header['CUNIT2'] = 'arcsec'
+
+# Now we can pass in the data and header directly into `sunpy.map.Map`
+lascomap = sunpy.map.Map(data, header)
+lascomap.peek()


Test patch: