Hello Friends
Web master tool provide all back links data, crawl error data etc.and analytic it provide following information:visitor reports,web traffic reports,details of keywords,content
conversions.

google analytics give you visitor report, traffic report
google web master tools give you crawl error and link

Google analytic gives the information about website's visitors, goal, transaction, visit source and much more but Google webmaster is different here you can add disavow, robots and sitemap file and also can call google crawler for crawling by fetched links.

If you can find any error for your website then Google Webmaster Tool can able to provide you idea for solving it. Webmaster tool is used for maintenance for a website, it helps to search all backlinks for a website.

Thanks For Sharing This information :)