For XML Sitemaps, can a document contain multiple Protocol Extensions?

Question

I did a lot of research before asking this question. I even went to Google and searched for "sitemap" filetype:xml -- to look at some big-league sitemap files to see if there was an answer here.

Actual Question:

1. XML sitemaps support "extensions": https://www.sitemaps.org/protocol.html#extending
2. Google supports News, Images, Video and Generic: https://support.google.com/webmasters/topic/6080646?hl=en&ref_topic=4581190
3. It also supports multi-lingual content: https://support.google.com/webmasters/answer/2620865?hl=en&ref_topic=6080646
4. It also supports, "sitemap indexes": https://support.google.com/webmasters/answer/75712?visit_id=1-636476631020171976-2911222833&rd=1

Can an XML Sitemap make use of multiple extensions at once?

I cannot find an example of anyone doing this in the wild. Which means that either it will not work or there's a really good reason for not doing this. But there's no supporting information that I can find about this.

---

Sitemap Indexes being their own document makes sense because the XSD file has to be different: https://www.sitemaps.org/schemas/sitemap/0.9/

But looking here: https://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd -- I didn't find any clues... then Nike's XML document: https://store.nike.com/sitemap-store-en-ca.xml

It has:

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:news="http://www.google.com/schemas/sitemap-news/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:mobile="http://www.google.com/schemas/sitemap-mobile/1.0" xmlns:image="http://www.google.com/schemas/sitemap-image/1.1" xmlns:video="http://www.google.com/schemas/sitemap-video/1.1">

But the content of the sitemap is still normalized, there's not a mixture of nodes.

Going to https://www.google.com/schemas/sitemap-image/1.1/ I see:

Google uses XML schemas to define the elements and attributes that can appear in your Sitemap file. A Sitemap may contain both core Sitemap elements and elements specific to Images.

I'd really love to know, could I have, let's say a blog -- then an XML Sitemap that houses the URLs to the articles, the URLs, the translation XHTML nodes, the images I'd like indexed for that URL, videos on that URL and such all in one...

Could you go to http://www.cnn.com/sitemaps/sitemap-gallery-2017-11.xml and within the urlsets, add video content in parallel with the image content?

Answer 1

This is supported by at least Google. If you look under the XML sitemap format here: https://support.google.com/webmasters/answer/183668?hl=en

You'll find this example where they mix image and video nodes.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" 
  xmlns:image="http://www.google.com/schemas/sitemap-image/1.1" 
  xmlns:video="http://www.google.com/schemas/sitemap-video/1.1">
  <url> 
    <loc>http://www.example.com/foo.html</loc> 
    <image:image>
       <image:loc>http://example.com/image.jpg</image:loc>
       <image:caption>Dogs playing poker</image:caption>
    </image:image>
    <video:video>
      <video:content_loc>
        http://www.example.com/video123.flv
      </video:content_loc>
      <video:player_loc allow_embed="yes" autoplay="ap=1">
        http://www.example.com/videoplayer.swf?video=123
      </video:player_loc>
      <video:thumbnail_loc>
        http://www.example.com/thumbs/123.jpg
      </video:thumbnail_loc>
      <video:title>Grilling steaks for summer</video:title>  
      <video:description>
        Cook the perfect steak every time.
      </video:description>
    </video:video>
  </url>
</urlset>

I took a look at the XSD for the image namespace here: http://www.google.com/schemas/sitemap-image/1.1/sitemap-image.xsd

The schema definition for these nodes does not have any requirements about sibling nodes and you should be able to drop these mixed sitemap node types within a urlset.