Paul- Well said! -Don > From: [email protected] > To: [email protected] > Subject: [ENTS] Re: Lidar data availability and possible application > Date: Sat, 7 Mar 2009 11:56:10 -0600 > > > There are always potential sources of errors in any data set. Subfoot > accuracy can be expected from small beam widths with more than one sample > per square meter. Dense forest canopy can prevent accurate modeling of the > bare earth beneath it. Large flocks of large migratory birds might affect > it. Humps and rises may not appear in dense forested datasets. Improper > filtering of ground data may cause gross errors in height data. I'm not > sure how quickly the airborne GPS reacts to updrafts and downdrafts during > the data taking flight. I'm sure there are other sources of errors. Ground > verification will always be necessary. LiDAR won't replace field work, but > could guide one to areas of high likelihood of success, definitely an > improvement over random searches through large areas of old growth. > > Paul > > ----- Original Message ----- > From: "Bruce Allen" <[email protected]> > To: <[email protected]> > Sent: Saturday, March 07, 2009 11:40 AM > Subject: [ENTS] Re: Lidar data availability and possible application > > > > Will, > > It may not be 150, but in our plot it seems to be consistently > 120-130+. And these are young trees (for cypress <120 years old), few > over 1 m, over 600/ha, high basal area- 70m2/ha. > > When I looked at the Parks canopy map, very few areas were over 100 > feet tall. That just isn't accurate. > > Bruce > > On Sat, Mar 7, 2009 at 12:34 PM, Will Blozan <[email protected]> > wrote: > > > > Paul, Bruce, > > > > I briefly looked at the LiDAR data at Congaree last visit and found some > > glaring "errors". The highest forest canopy was generally the pine groves > > but one tupelo/cypress swamp had a 150'+ canopy over dozens of acres. That > > is simply not possible. > > > > Will F. Blozan > > President, Eastern Native Tree Society > > President, Appalachian Arborists, Inc. > > -----Original Message----- > > From: [email protected] [mailto:[email protected]] On > > Behalf Of Paul Jost > > Sent: Saturday, March 07, 2009 12:23 PM > > To: [email protected] > > Subject: [ENTS] Re: Lidar data availability and possible application > > > > > > Bruce, > > > > I don't expect LiDAR to measure tree heights very accurately, especially > > in > > free USGS data. I hope that it can help locate potential tall trees that > > can be found on the ground and then measured accurately by ENTS methods. > > It > > > > could help focus searches on large public lands that would otherwise take > > many lifetimes to effectively explore. > > > > Paul > > > > ----- Original Message ----- > > From: "Bruce Allen" <[email protected]> > > To: <[email protected]> > > Sent: Saturday, March 07, 2009 6:49 AM > > Subject: [ENTS] Re: Lidar data availability and possible application > > > > > > > > In the Congaree, Lidar doesn't seem to pick up the highest small > > branches. If you looked at the Park Services canopy height map it > > just doesn't seem to pick up the max height effectively. > > > > Bruce > > > > On Fri, Mar 6, 2009 at 11:32 PM, Paul Jost <[email protected]> wrote: > >> > >> Gary, > >> > >> With regards to the application of LiDAR data to our tall tree searches, > >> when I've worked out the bugs as much as reasonably possible, I'll post > >> some > >> screen shots and some info on the process so that others can do the same > >> thing for FREE!! It should be in the next week or so.... > >> > >> Paul > >> > >> ----- Original Message ----- > >> From: <[email protected]> > >> To: <[email protected]> > >> Sent: Friday, March 06, 2009 8:26 PM > >> Subject: [ENTS] Re: Lidar data availability and possible application > >> > >> > >>> Thanks Paul. I am enjoying your posts. > >>> > >>> Gary > >>> Sent via BlackBerry from T-Mobile > >>> > >>> -----Original Message----- > >>> From: Paul Jost <[email protected]> > >>> > >>> Date: Fri, 06 Mar 2009 18:45:03 > >>> To: <[email protected]> > >>> Subject: [ENTS] Re: Lidar data availability and possible application > >>> > >>> > >>> > >>> Gary, > >>> > >>> I'm using free LiDAR data from the USGS product page with free FUSION > >>> software from the U. of Washington. > >>> > >>> Paul > >>> > >>> ----- Original Message ----- > >>> From: <[email protected]> > >>> To: <[email protected]> > >>> Sent: Friday, March 06, 2009 6:34 PM > >>> Subject: [ENTS] Re: Lidar data availability and possible application > >>> > >>> > >>>> Paul, > >>>> > >>>> Just joining the list after a hiatus and I am interested in what you > >>>> are > >>>> doing. I have ArcGIS 9.3 and now a Magellan Mbile Mapper 6. Did you buy > >>>> the LIDAR? > >>>> > >>>> Gary > >>>> Sent via BlackBerry from T-Mobile > >>>> > >>>> -----Original Message----- > >>>> From: Paul Jost <[email protected]> > >>>> > >>>> Date: Fri, 06 Mar 2009 18:28:27 > >>>> To: <[email protected]> > >>>> Subject: [ENTS] Re: Lidar data availability and possible application > >>>> > >>>> > >>>> > >>>> Josh, > >>>> > >>>> I've been working on the Wright Creek LiDAR data and need to finish > >>>> working > >>>> on optimizing the generation of the bare earth topographical layer from > >>>> the > >>>> LiDAR data. Preliminary work shows quite a few trees in the 140's, a > >>>> few > >>>> in > >>>> the 150's, and possibly one around 171 feet tall. This software is > >>>> pretty > >>>> cool. I can measure individual trees, color by tree height, etc. > >>>> > >>>> I need to verify if any are outliers or noise but would like to ground > >>>> check > >>>> some. I also haven't checked out much of the creek yet. Did you GPS any > >>>> of > >>>> the trees when you were there? If so, can you enter a user coordinate > >>>> system in your GPS? I'm working in State Plane for NC in feet, the form > >>>> that the LiDAR data comes in. I can give you info on how to set up user > >>>> coordinate systems in your GPS if you used it there. Otherwise, I'll > >>>> have > >>>> to find a way to convert the coordinates myself - easier to do with the > >>>> more > >>>> expensive GIS software. > >>>> > >>>> Paul > >>>> > >>>> ----- Original Message ----- > >>>> From: "Josh Kelly" <[email protected]> > >>>> To: "ENTSTrees" <[email protected]> > >>>> Sent: Monday, March 02, 2009 3:56 PM > >>>> Subject: [ENTS] Re: Lidar data availability and possible application > >>>> > >>>> > >>>>> > >>>>> Paul, > >>>>> > >>>>> Let me know how using the LIDAR data around Santeetlah goes. If you > >>>>> find any great trees, I could ground truth them next time I return to > >>>>> the area. I'm quite sure there are 160' poplars in the area (second > >>>>> growth) and maybe some 170's. > >>>>> > >>>>> Josh > >>>>> > > >>>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > > >>>> > >>> > >>> > >>> > >>> > >>> > >>> > > >>> > >> > >> > >> > >> > > >> > > > > > > > > -- > > Bruce P. Allen > > Springfield, NH > > > > > > > > > > > > > > > > > > > > > > > -- > Bruce P. Allen > Springfield, NH > > > > > > >
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