I recently made several major structural changes to my website, added, deleted many of my pages, and changed my keywords and HTML tags. Should I re-submit my XML sitemap from my Google webmaster tool to Google after I am done with all of the major modifications? Thanks ...
I recommend resubmit sitemap your website . Because Google has indexed old link , old structure web .You need to resubmit to google follow new link (Sorry because I speak English not good)
In my opinion resubmitting the sitemap is very beneficial for the re-indexing of your pages. I have made large changes to my meta info and wanted my pages reindexed its been a week and 3700 out of 8700 are finished.
I still think sitemap play a positive role in helping my website indexed faster. Also it helps you keep track of how many URLs of your website is actually indexed. If the number of indexed URLs is low then you know that you will have to do something about it.
Site map is definitely very important, re-submitting it through Google webmaster tool allows them to visit and re-index pages frequently.
If you'll not re-submit your sitemap it means google is unknown from your new links that you created and those links will not be indexed. So sitemap re-submission is very important.
you definitely resubmit your sitemap because in old pages you have less probabilities in frequency of daily bases first you have to generate the site sitemap with any sitemap generator then submit on webmaster tools.