Is it necessary to include both html and xml?

I am trying to be as compliant and Search engine satisfying as possible in my practices. Is it necessary to include both html and xml versions of your sitemap? An addition, Im familiar with styling and linking and displaying html 开发者_如何转开发files, but not so much for xml? Is there anything I have to do to make a successful xml sitemap?

No need to have both htm and xml. Read this "Creating Sitemaps" article on Google's Webmaster Tools.

In most cases sitemap is not necessary at all.
If there are no links to your pages, the sitemap will not help you.