How do geographers/surveyors determine the true source of major rivers like the Amazon?

No formula...A team of explorers usually start where the river dumps into the ocean or other main artery, and ends... and then travel up , or back track the river to its beginning, where ever that may be. They map and take measurements using sophisticated computer analysis programs checking water flow and depth. all along the way, so they are not only mapping the coast line of the river, but volume of water passing through it too.. As that is also a factor in determining the size of a river. This is truly the only way to accurately find a rivers source. You must follow it back. Brazil, now claims after this latest exploration, the Amazon actually begins as melt run off from under a Glacier.

Hope this helped

No, not at all. Eddie is quite right in saying that Christianity's version of "messiah" is completely at odds with Judaism's. That's just the tip of the ice berg. Christianity has to rely on dodgy 'translations', invented words, altered verb tenses and a general refusal to read entire passages or use context to sledgehammer its pagan salvation theology into Jewish texts. Judaism has a collection of sacred texts. Several times throughout history, outsiders took them and made something not quite new but completely un-Jewish. Two of those have survived as Christianity and Islam. So, no. Judaism is NOT the source of the other two.

Well, they probably find the end of the river, take some doo-dad or another (don't blame me, i don't measure rivers) and walk, most likely, all the way to the begining of the river. And for deciding the regions, they do probably have a formula for that, but I would just divide the total number by three, one for upper, one for middle, and one for lower.

*shrugs* hey, if I sound like a moron, quite frankly, I don't care. And I am very literate, I'm a book worm... :P

They begin by identifying the continental divide, the boundary between to drainage basins, the highest point on the ridge. In Peru, it would be the Andes, dividing rivers flowing west to the Pacific and east to the Atlantic. I think they find the tributary that is furthest from the mouth of the main river on that side of the continental divide.

I'm pretty sure that many kinds of measurements had be taken over & over to gain what might be seen as thee,' best possible choice in determaing distance,depth,speed,temperature,density,brilliance,mass`so'forth to determain the properties & or make-up of things !! try contacting a site concerning oceanography or something to that effect !?! "R"r`r,r-{7/5/07]

they explore