Using views to find list of users nearby using location in arguments I am using drupal 6.X
I am creating an api through views and views datasource module 
in which i will add the latitude and longitude of the location in the end of the url as we define the arguments in the view so that i can get the list of users in the order of the nearest first.
I think you are telling about the proximity search and you want to display the user/nodes with in a particular distance based on the location of a single user/node.

You can select the "location" in the filter and there you can see the distance/proximity option