Larry- As a field forester for much of my life, my most valuable and accompanying tools in the woods were a Silva Ranger compass, a Suunto clinometer, a rag tape, a topo map, and a stereo pair of aerial photographs. Like Paul, those tools were of inestimable value in getting around in the woods. Still are. It's only now in my retirement that I've considered getting a GPS. One tool that evolved from this original set, came through the technological advantage of being a GIS technician. When I was tasked with assembling a vegetation map for Grand Canyon (for input into a fire area growth model), the morphing of a topo map onto an aerial photograph was the very synergistic result. Taking digital versions of each allowed the overlaying of separated layers of a topo, onto a digital orthophoto quad (a digitized aerial photograph). The result was the best of both worlds. I was often heard saying in those times, that you could almost 'see the topo contours on the ground' when walking in the field with these 'ortho-photo' maps. One of the benefits of these maps was when you made changes in vegetation type delineations in the field, back in the office, you didn't have to rescale...you brought up the same imagery in a GIS, moved the field changes into the office copy and you were done. But I do like GPSs for similar tasks...but much more care needs to be taken to be able to transfer GPS data into a GIS environment...instead of just grabbing a coordinate pair, you need to 'average' the point, and post process to get the accuracy required for topo standards. Handheld GPS accuracy often times 'hovers' around the thickness of a line on a topo map. -Don
> From: [email protected] > To: [email protected] > Subject: [ENTS] Re: GPS > Date: Thu, 5 Mar 2009 09:12:20 -0600 > > > I've never spent the money on that stuff yet. There is so much free > publicly accessible aerial imagery and topographic maps for the entire > country that I never thought that it was worth it to me to have the software > with the little extra functionality - the 48 contiguous states have nearly > complete coverage with free downloadable data from government sources such > as the USDA, USGS, AmericaView, and most state's GIS departments. I print > out aerial photos and topo maps for free for where ever I go and sometimes > enter waypoints on my GPS since I rarely want to follow an exact preplanned > route. I'm not sure what else you gain by spending the money on the > software. Maybe I'm a little old fashioned. I use the GPS as a > navigational aid only when needed and to mark trees, but try to rely on > compass and map skills to save the gps batteries and to not become to > reliant on it. > > Paul > > ----- Original Message ----- > From: "Larry" <[email protected]> > To: "ENTSTrees" <[email protected]> > Sent: Thursday, March 05, 2009 7:36 AM > Subject: [ENTS] Re: GPS > > > > > > Will, Paul, et al, Should I get the 2008 mapsource software with this > > gps, I noticed they have several regions? Larry > > > > > > > > > > > > _________________________________________________________________ Windows Live™ Contacts: Organize your contact list. http://windowslive.com/connect/post/marcusatmicrosoft.spaces.live.com-Blog-cns!503D1D86EBB2B53C!2285.entry?ocid=TXT_TAGLM_WL_UGC_Contacts_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 -~----------~----~----~----~------~----~------~--~---
