Merge pull request #190 from NASA-NAVO/trjaffe-patch-1

remove sdss

content/reference_notebooks/image_access.md

@@ -48,9 +48,6 @@ In this notebook, we show how to search for and retrieve images from VO services
   - [3. Viewing the resulting image](#3-viewing-the-resulting-image)
     - [JPG images](#jpg-images)
     - [Fits files](#fits-files)
-  - [4. Example of data available through multiple services](#4-example-of-data-available-through-multiple-services)
-    - [Using HEASARC](#using-heasarc)
-    - [Using SDSS SkyServer](#using-sdss-skyserver)
 
 +++
 
@@ -156,61 +153,3 @@ hdu_list.info()
 ```{code-cell} ipython3
 plt.imshow(hdu_list[0].data, cmap='gray', origin='lower',vmax=0.1)
 ```
-
-## 4. Example of data available through multiple services
-
-Suppose we want Sloan DSS data.  A generic query finds us a number of possibilities (note that this doesn't work for keywords=['sdss'];  be flexible and try several search terms):
-
-```{code-cell} ipython3
-services = vo.regsearch(servicetype='sia', keywords=['sloan'], waveband='optical')
-services.to_table()[np.where(np.isin(services.to_table()['short_name'], 'SDSSDR7'))]['ivoid', 'short_name']
-```
-
-So one of these is served by SDSS's SkyServer and the other by HEASARC's SkyView.
-
-+++
-
-### Using HEASARC
-
-```{code-cell} ipython3
-heasarc_dr7_service = [s for s in services if 'SDSSDR7' in s.short_name and 'heasarc' in s.ivoid][0]
-
-sdss_table_heasarc = heasarc_dr7_service.search(pos=coords,size=0.2,format='image/fits')
-sdss_table_heasarc.to_table()
-```
-
-```{code-cell} ipython3
-## If you only run this once, you can do it in memory in one line:
-##  This fetches the FITS as an astropy.io.fits object in memory
-# hdu_list = sdss_table_heasarc[0].getdataobj()
-## But if you might run this notebook repeatedly with limited bandwidth,
-##  download it once and cache it.
-
-#  Get the filter g version
-file_name=download_file(sdss_table_heasarc[0].getdataurl(), cache=True, timeout=600)
-hdu_list = fits.open(file_name)
-
-plt.imshow(hdu_list[0].data, cmap='gray', origin='lower', vmax=1200, vmin=1010)
-```
-
-### Using SDSS SkyServer
-
-```{code-cell} ipython3
-jhu_dr7_service = [s for s in services if 'SDSSDR7' in s.short_name and 'jhu' in s.ivoid][0]
-
-# Note: jhu_dr7_service access url has hard-wired "format=image/fits".
-# If you specify anythign else, it errors. If you specify nothing,
-# then the search() method puts "format=all", which errors. So specify "format=None" for now.
-sdss_table_jhu=jhu_dr7_service.search(pos=coords,size=0.2, format=None)
-sdss_table_jhu.to_table().show_in_notebook(display_length = 5)
-```
-
-```{code-cell} ipython3
-#  Get the filter g version
-file_name=download_file(sdss_table_jhu[1].getdataurl(), cache=True, timeout=600)
-hdu_list = fits.open(file_name)
-
-plt.imshow(hdu_list[0].data, cmap='gray', origin='lower',vmax=1200,vmin=1010)
-```
-
-It turns out that SkyView is just getting images by using the SIAP internally to get the data from the SDSS service.  The point of the VO protocols is that you don't need to know where the data are coming from.  But they can be processed differently.