Pgoodwin1 said it nicely.
With the same token, considering the data we access can and does pull from various locations globally. Therefore many times it is more than necessary to have the ability to test from / to multiple geographical locations to verify possible choke points in a network.
To gain insight as to your connection specific global weight, testmy.net has featured what it coins as 'multi' or multiple threaded tests, simultaneously pulling from as many as nine (9) specifically located test servers placed around the world, in some of the most highly connected fiber backbone sectors. With this, you are able to chose as little as one test point, with any combination of the nine, or select **all locations.
This type of testing is mimicking how the web browser performs in real time as you browse sites that, as most are, implementing code which pulls resources from as little as one to the possibility of unlimited global resources. Printing unparalleled real world results.
This test resource, located at multi geographical location testing has the ability to inform you as to not only how well your ISP is peering with local as well as geographical providers, but how the chosen path is performing on any specific resource.
** Dallas, TX US => testmy.net (shortcut: select by itself for auto mix)
Washington D.C. => east.testmy.net
Cloudflare (Global CDN) => cloud.testmy.net
San Jose, CA US => west.testmy.net
Google Pagespeed (Global CDN) => google.testmy.net
Dallas, TX US => dallas.testmy.net (DNS resolution for targeted selection)
London, GB => uk.testmy.net
Melbourne, AU => au.testmy.net
Hong Kong, CN => cn.testmy.net