Is it possible to design my sitemap hierarchically?
My site is laid out hierarchically into
Can I design my sitemap xml like this? Is there a benefit?
It is not possible to define any hierarchal structure in your XML sitemap. The XML sitemap is a straight forward list of all your pages. Any hierarchal structure to your pages will be determined by Google when it crawls your site.
The hierarchal structure is more relevant to your users. So, your HTML sitemap (if you have one) could be defined in this way. Perhaps using a series of nested lists.
Sitemap is essentially an unordered set of URLs, each of them with information about priority, last change, and expected frequency of change. We could imagine the priorities as a kind of linear ordering of the URLs, but that would be the only "layout" possible.
If the site contains too many URLs, it can be split into multiple Sitemaps, linked from one Sitemap Index. It may seem like a hierarchy, but it is not -- it is just a way to split one long file into multiple files, so that google does not have to download too much data together; but in the end, the data are joined into one big set.
If you want to somehow support your hierarchical structure by Sitemap, you could assign various nodes priorities depending on their depth in hierarchy. For example the "World" could have priority 1.0; each "Continent" 0.9; each "Country" 0.8; each "State" 0.7; each "City" 0.6; and you could still use numbers from 0.5 to 0.1 to prioritize different "Articles".
The benefit of doing so is that when people search for some keywords, they will find the most general page relevant to this keyword. For example if you provide the same text in the description of Europe, France, and Paris, the google results will put Europe first. Which may or may not be what you want.
Sitemap index file can list multiple sitemaps see sitemaps.org.