Larry- What you gave me was lats and longs. All two dimensional maps (flat, on paper) are projected. All projections have datum. If you pick up any USGS topo map, you'll see along the edges that they have a datum...in many cases they will say 1928, or if more current, they might say 1984...there are variations, depending on what part of the US you are in, but most fall in those two datums. What's the difference? Depends on where you are at, but if I recall correctly Massachusetts's datums are different by something like 29' North to South and 7 or 8' East to West. I could be way wrong, as my short term memory loss is cutting an ever bigger swath these days. The point is, and I tried to send a email post in time, that you all should have been on the same datum (it's a setting in your GPS, one of maybe a hundred different datums that it takes to "project the world", because the world isn't perfectly round), when you were going out to collect data on the Congaree. Could you have done so, and should somebody wanted to put your tree locations on a map, in a GIS, it would have been helpful for the GIS guy for you all to be in the same datum...now, you'll need to find out what datum your GPS was in, and make sure that you provide the database person with your datum, your lat long coordinates or state plane coordinates, or whatever coordinate system you were collecting data (these are all called 'meta-data', data about your data...;>) Sorry, got to rambling, sure this is more than you wanted to know! -Don
> Date: Wed, 4 Mar 2009 17:08:03 -0800 > Subject: [ENTS] Re: GPS > From: [email protected] > To: [email protected] > > > Don, Thats what I need to understand better. Lat and Long say like > 33 88.427 80 52.897 In degrees minutes and seconds. Explain the > other datum to me please. Larry > > > > _________________________________________________________________ Windows Live™ Groups: Create an online spot for your favorite groups to meet. http://windowslive.com/online/groups?ocid=TXT_TAGLM_WL_groups_032009 --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
