-------- Original Message -------- Subject: Re: High-accuracy GPS Date: Wed, 15 Dec 2010 01:20:20 EST From: [log in to unmask] To: [log in to unmask] I have a simple suggestion. Sounds almost too simple but has worked for me. I map individual gravestones in cemeteries with my handheld Garmin. I set the GPS unit on the stone and wait until it has acquired its satellites. I take a reading. I wait 8-10 more minutes and take another reading. Then I wait one more time 8-10 minutes and take a third reading. The idea being that the satellites are moving around in space with sometimes more satellites acquired than other times. After three readings I can "average the data". Most of the time the three readings are very close to one another with only the most minute differences. The downside is that mapping this way takes a long time and it is an exercise in patience when I use student help. The upside is that I am not out thousands of dollars for a GPS unit. Barring any interference such as trying to take readings under tree canopies, readings next to buildings, or readings next to extensive areas of shiny marble, most of the time this very simple method works in cemeteries. It might work in botanical gardens too. Best Wishes, Melinda Kashuba Redding, California In a message dated 12/14/2010 1:57:04 P.M. Pacific Standard Time, [log in to unmask] writes: -------- Original Message -------- Subject: High-accuracy GPS Date: Tue, 14 Dec 2010 13:31:18 -0800 From: Dyallen2 <[log in to unmask]> To: [log in to unmask] Has anybody on this list had experience using high-accuracy GPS? I am involved in a GIS project with my local botanical garden, which requires mapping individual plants with sub-meter accuracy. Most systems that do this seem to cost upwards of $10,000, which is beyond our reach. I stumbled across some information about a DeLorme product called Blue Logger GPS, which claims to do this for about $1000. Has anybody had success using this system, or have other suggestions for low-cost, high-accuracy GPS? David Allen (retired from Stony Brook University, now volunteering for San Diego Botanic Garden)