I used DGPS for forest plots in tropical areas: as already sugg Hello, I used DGPS for forest plots in tropical areas: as already suggested better to establish the plot reference point, as it can take long time to record it properly, and worse if you have to reach a specific point.
I had serious troubles with Trimble GH: once you collect data you can usually enter a online service (i.e Auspos) for differential correction.... Trimble rinex outputs have proprietary software issues (curring one of the two frequencies) which made very difficult the use of this online systems, which are a must in developing countries where few bases exist. I found a solution using Leica instead, which has more robust sw and less exporting problems, according to my experience hope it helps Gaia V Laurin Post-doc, CMCC/Iafent Italy ________________________________ From: Thiago S. F. Silva <[email protected]> To: [email protected] Sent: Monday, October 29, 2012 12:58 AM Subject: Re: [ECOLOG-L] differential gps advice, please As an aside, if you're doing plots, it is better to establish a single reference point for each plot using the gps, and then record the location of each plant using horizontal surveying (e.g. bearing and distance of each plant from the reference point), than getting a GPS location for each individual shrub. That will give you a much higher relative precision for the location of each plant in relation to the others. In fact, if you're only interested in the accuracy of these relative positions (let's say, if you're looking at plant spatial distribution), you might not even need the DGPS. All your points will have the same absolute position error from the GPS used for the reference point, but will still be very accurate in relation to each other. Best, Thiago S. F. Silva Instituto Nacional de Pesquisas Espaciais (INPE) On Sunday, October 28, 2012, Tim Farkas wrote: > Hi Ecologers, > > I'm planning a field study in which I need to achieve ~30cm precision in > marking the locations of shrubs in a mountainous landscape in southern, > coastal California. I have been told that differential GPS may be our > solution. There's a lot of stuff out there on the web, so I'm a little > overwhelmed with the apparent options. Also, when researching this a few > years ago, I read about needing permission from the government for this > kind > of mapping precision. Is that true? > > Can anybody provide a source of recommendations for DGPS units, caveats of > their use, etc.? > > Help much appreciated. > > Cheers, > > tim > -- > -- -- *Dr. Thiago Sanna F. Silva* Postdoctoral Fellow Remote Sensing Division - Instituto Nacional de Pesquisas Espaciais (INPE) São José dos Campos, SP - Brazil www.dsr.inpe.br Personal Webpage: www.thiagosilva.wordpress.com https://plus.google.com/101212496230661235420
