Thanks Paul! I'm on it! Now if I can view the LIDAR images in ArcPad on my Magellan Mobile Mapper 6 it will be swweeet!
Gary Sent via BlackBerry from T-Mobile -----Original Message----- From: Paul Jost <[email protected]> Date: Sat, 07 Mar 2009 11:10:31 To: <[email protected]> Subject: [ENTS] Application of USGS LiDAR data to ENTS, North Carolina example, part 1 Gary, In the past I played with Landsat HDF files but had a difficult time classifying the data. The resolution also wasn't useful for my/our purposes, so I gave up on it. I looked at AVHRR, SIR-C and SAR and couldn't find practical applications of that data to ENTS functions. On the other hand, the LiDAR is great. The Fusion demo data is higher resolution than the USGS online data, and gives a good picture of it's potential usefulness. From what I have seen so far, the USGS data has good enough resolution to find and measure tall trees in a large landscape. We don't know how badly any of them are mismeasured badly yet, but it at least allows us to focus our searches a little better. Here's what I've done so far: Downloaded Fusion software and sample data from the "Projects" "FUSION/LDV" frame: http://forsys.cfr.washington.edu/ Downloaded Fusion tutorial pdf and data files from: http://www.fs.fed.us/eng/rsac/fusion/ Get familiar with software. Go to USGS LiDAR web site, use HTML/Java viewer to see where data is available. http://lidar.cr.usgs.gov/LIDAR_Viewer/ Download the .kml or .kmz file to better locate exact desired LiDAR tile data LAS file in GoogleEarth or ESRI ArcGis Explorer: At least for North Carolina, they are georeferenced to four tiles per DOQQ, which is 16 tiles per 7.5 minute topographic quadrangle. North Carolina has total coverage, Lousiana has partial coverage at USGS and more coverage at a LSU web site, other locations are spotty coverage with additional free data available from the state university GIS web sites, or free or for pay data from state, county, or local governments. Once I had a LAS format LiDAR data tile from the USGS, I needed an image file for the same tile. DOQQ or digital orthophoto quarter quadrangles based upon 1/4 of a 7.5 minute topographic quadrangle, are available for most of the U.S. from the USGS and state GIS departments. There are recent free medium and high resolution ortho imagery files available from: http://datagateway.nrcs.usda.gov/GatewayHome.html and also from member states sites of the AmericaView program. Wisconsin's is: http://www.americaview.org I got my North Carolina file from I got mine from North Carolina's GIS site hoping that it would be in the same projection as their LiDAR file. They were, but the only difference was one was in feet and the other was in meters: http://www.cgia.state.nc.us/DataResources/tabid/55/Default.aspx I tried their online viewer, but I can't get it to work properly on my computer at home or work: http://204.211.239.202/viewer/ So, I manually found out which quarter quad (DOQQ) image I needed from their ftp download site: http://www.nconemap.net/Default.aspx?tabid=286 Here, I got a 1998 DOQQ CIR MrSID file and the metadata info. First, I browsed the DOQQ names on the pdf index reference file: ftp://204.211.239.203/outgoing/raster/doqq/cir_1998/ Then downloaded santck1 data from the directories down the folder tree. Fusion can't read MrSID files, so I used free time-limited LizardTech GeoExpress View software to convert it to a properly georeferenced TIFF with a world file that I could edit. http://www.lizardtech.com/download/dl_options.php?page=viewers I couldn't find any other free software that would give me the conversion in the same resolution and without messing up the georeferencing. Their plug-in version reduces the image resolution to the screen resolution. The .tfw file is not in the correct units for Fusion. I had to convert it from meters to feet: Original santck1.sdw world file data, (x-scaling, y-scaling of x data, y-scaling, x-scaling of y-data, x offset, y offset): 1.000000000000000 0.000000000000000 0.000000000000000 -1.000000000000000 155061.204046555270907 191808.684446442872286 Conversion tables scale 1 meter = 3.2808 feet. By scaling the values from DOQQ metadata, the ratio of the LAS to image data can be properly scaled. A little error on a large data set will create a large error at the end of the x and y data. From the metadata files, I determined the following conversion factor: LiDAR LAS Projection false easting = 2000000.002617 feet DOQQ Projection false easting = 609601.22 meters 2000000.002617 /609601.22 =3.2808333333338801388881734849546 I know, there are too many digits beyond the significant ones, but I just cut and pasted out of the Windows calculator. I multiplied all the entries in the world file by this amount to scale the data to units equivalent to the LiDAR LAS data file. The resulting properly scaled santck1.tfw world file is: 3.2808333333338801388881734849546 0.0 0.0 -3.2808333333338801388881734849546 508729.96694282487296176202528535 629292.32555480953887910689675521 Both the LAS and TIF(TFW is automatically imported when the TIF is read) are input data files for Fusion. This allows viewing of 3D surface data with color coded heights or color by image data for the data set with little user experience. What I'm doing now is using the groundfilter and gridsurfacecreate command line tools to generate bare earth data to allow individual tree measuring. I need to optimize the filter coefficients to get better results than the default values allow. So, far the default values provide a surface with significant outliers. They are above ground outliers, so they only make some trees appear shorter, not taller. Once that work is done for the USGS datasets, the commands can be entered in a batch file to allow anyone to use the data from USGS regardless of location. I'll post another message with screen shots showing individual tree measuring and 3D landscapes once I optimize the ground filtering for some more reliable data. Paul J. ----- Original Message ----- From: "Gary A. Beluzo" <[email protected]> To: <[email protected]> Sent: Saturday, March 07, 2009 7:20 AM Subject: [ENTS] Re: Lidar data availability and possible application > > Paul, > > Have you worked at all with some of the other types of remote sensing > such as LandSat, AVHRR, etc? I know Don B was working with > multispectral imagery in grad school but didn't have very much luck > with it because of confounding variables such as light variation and > spurious texture surfaces. I wonder if Don has made any progress with > that imagery? One of my grad committee members (and I think perhaps > Don's), Jack Finn, has been doing work with multispectral imagery and > aerial videography with some success for GAP analysis. Not sure to > what extent it would be useful to ENTS because the resolution is low > (30m x 30m). > > LIDAR has great potential for our work. Thanks for taking the > initiative to bring this technology to ENTS. > > Gary > On Mar 6, 2009, at 11:32 PM, Paul Jost 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 >>>>>> >>>>> >>>> >>>> >>>> >>>> >>>> >>>>> >>>> >>> >>> >>> >>> >>> >>>> >>> >> >> >> >> > > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
