The basic structure

2007-05-29T01:18:00.000-07:00

XML is a scary set of three letters for some, it stands for Extensible Markup Language. XML in real life is not all that scary, in it's most basic definition it is a language used to describe data. The Data it describes is in the bits between tags which tells what ever is going to read it, what that data actually is.

In our little corner of the XML universe all we care about is how to describe a site map to a search engine such as Google using XML.

A sample Sitemap that contains just one URL and uses all optional tags is shown below. The optional tags are in italics.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.google.com/schemas/sitemap/0.84">
<url>
<loc>http://www.example.com/</loc>
<lastmod>2005-01-01</lastmod>
<changefreq>monthly</changefreq>
<priority>0.8</priority>
</url>
</urlset>

Wait! what is this and what does it mean???

Well, the entire listing is XML, the first line is

<?xml version="1.0" encoding="UTF-8"?>

Which describes exactly what it looks like, it's XML, the XML version is 1.0 and the text encoding is UTF-8.

Okay, the UTF-8 part is not as straight forward as you were hoping.
So UTF-8:

UTF-8 (8-bit UCS Unicode Transformation Format) is a variable-length character encoding for Unicode. It is able to represent any universal character in the Unicode standard, yet the initial encoding of byte codes and character assignments for UTF-8 is consistent with ASCII (requiring little or no change for software that handles ASCII but preserves other values). For these reasons, it is steadily becoming the preferred encoding for e-mail, web pages, and other places where characters are stored or streamed.

Okay, enough... For more info on UTF-8 go here: http://en.wikipedia.org/wiki/UTF-8

Let's un-digress, So the first line will always be the first line in your sitemap.
<?xml version="1.0" encoding="UTF-8"?>

The second line in the XML example is:
<urlset xmlns="http://www.google.com/schemas/sitemap/0.84">

This is the open tag for the set of URLs (urlset) xmlns stands for "XML namespace". A namespace is a unique identifier for a variant of XML. It is a method to avoid conflicts with different XML variants which use the same element names.

You don't have to really care too much about what /sitemap/0.84 is other than you want that information in your open urlset tag. It is the schema for the sitemap and you can look at the schema by clicking here.

The urlset tag wraps your entire set of URLs as you can see in the single url example above.

Cool, now we can play with the good bits, everything in the <url>...</url> tags.

Here we have our opening tag for our url description:
<url>

Next we have the location tag <loc>
<loc>http://www.example.com/</loc>

This is the actual URL of the web page in your site, for example, if this page were your about us page the above loc tag would look like this:
<loc>http://www.example.com/aboutus.htm</loc>
which is simply the URL of the page. This URL must begin with the protocol (such as http) and end with a trailing slash, if your web server requires it. This value must be less than 2048 characters.

The next three tags are optional but you probably want to put them in for good mesure.

the first is the last modified date: <lastmod>
<lastmod>2005-01-01</lastmod>

The date of last modification of the file. This date should be in W3C Datetime format. This format allows you to omit the time portion, if desired, and use YYYY-MM-DD and should change every time you update the web page.

The <changefreq> tag tells the reader how often the page is likely to change.
<changefreq>monthly</changefreq>
This value provides general information to search engines and may not correlate exactly to how often they crawl the page. Valid values are:

always

hourly

daily

weekly

monthly

yearly

never

The value "always" should be used to describe documents that change each time they are accessed. The value "never" should be used to describe archived URLs.

Please note that the value of this tag is considered a hint and not a command. Even though search engine crawlers consider this information when making decisions, they may crawl pages marked "hourly" less frequently than that, and they may crawl pages marked "yearly" more frequently than that. It is also likely that crawlers will periodically crawl pages marked "never" so that they can handle unexpected changes to those pages.

The <priority> tag
<priority>0.8</priority>
The priority of this URL relative to other URLs on your site. Valid values range from 0.0 to 1.0. This value has no effect on your pages compared to pages on other sites, and only lets the search engines know which of your pages you deem most important so they can order the crawl of your pages in the way you would most like.

The default priority of a page is 0.5.

Please note that the priority you assign to a page has no influence on the position of your URLs in a search engine's result pages. Search engines use this information when selecting between URLs on the same site, so you can use this tag to increase the likelihood that your more important pages are present in a search index.

Also, please note that assigning a high priority to all of the URLs on your site will not help you. Since the priority is relative, it is only used to select between URLs on your site; the priority of your pages will not be compared to the priority of pages on other sites.

And finally your closing </url> tag.

For each URL in your sitemap you will repeat the entire url tag sequence and then finally close it all off with your closing urlset tag.

Okay, let's toss it all together for a web site that has three pages.
the index, about us and reciprocal links.
Note the index.htm page in this example is simply / since that is our web site default page.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.google.com/schemas/sitemap/0.84">
    <url>
        <loc>http://www.example.com/</loc>
        <lastmod>2005-12-25</lastmod>
        <changefreq>weekly</changefreq>
        <priority>0.5</priority>
    </url>
    <url>
        <loc>http://www.example.com/aboutus.htm</loc>
        <lastmod>2005-12-24</lastmod>
        <changefreq>yearly</changefreq>
        <priority>0.5</priority>
    </url>
    <url>
        <loc>http://www.example.com/reciprocallinks.htm</loc>
        <lastmod>2005-12-27</lastmod>
        <changefreq>weekly</changefreq>
        <priority>0.5</priority>
    </url>
</urlset>

And that is it, you can apply this to all the pages in your web site, name it sitemap.xml place it in your root directory and go over and tell google it's there.

Next I will show you how to use the Google sitemap webmaster tool.

I hope this helps you in understanding sitemaps a little better.

SiteMaps made Simple

The basic structure