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Guest HeliFLYer

ROTW tutorial satelite scenery

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HiMaybe you have noticed. In the ROTW forum there are a lot of hints and tricks about making scenery from Landsat7 ETM+ Images.Unfortunately its in french, but with free translation tools from the internet it's understandable although funny to read.I have now downloaded my first images (4 different channels) and assembled them with Multispec as described into a colour-image.The process is straightforward and well documented by ROTW. It would have taken weeks for me to figure this all out.I hope someday's they will write a tutorial in english about the use of Landsat images.Thank You Harald

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Thanks for the greetings Harald !I have a small text file where I wrote all the tips & tricks I use since a few months working on this subject. It's not a tutorial but I'll try to translate it if you want.Anyway if you have some questions on the process, you can post even in english on the Simvol developpement forum. I hope I'll be able to help you :-walksmile

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HiThis small textfile with all the other discussion going on is exactly what I mean. Maybe if others see how simple and straightforward the process is, there will be more sceneries for europe.I think Georg (heliflyer) is also experimenting with satelite sceneries. So maybe we can bundle our effort.Thank you for your offerHarald

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At the moment, the biggest problem is the very variable quality of the 10m/pixel NIMA pictures. In many tile, I'll have to use only the poor 15m/pixel black&white landsat orthos as a main source.Roland

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Hi to all,as I am addressed in this post I want to give some information about my work with Landsat 7 textures. First I must say that the quality of my scenery cannot be compared with Rolands work. He does an outstanding job and produces really high-quality scenery. Due to heavy workload I had no time until now to read his paper how he does it in detail but he goes the way to combine the 30m/Pix LS7 with 10m/Pix NIMA, only sometimes uses the 15m/Pix b/w LS7. Result: hight quality output.My way is to combine the 30m/Pix LS7 with the 15m/Pix LS7 b/w doing some antialising and colour correction. I had to make some really time-consuming Delphi program to do that blowing up, combining, correcting and cutting on harddisk-memory as my PC crashed regularly when using some common graficprograms (though having 768 MB main RAM). The good side of that is getting a simple slicerfile (lat-lon-coordinates) for FLY! and the *.SCF file for the scenery produced by the process.I did not give any scenery to the community until now mainly because I could not manage a perfect matching of the FLY! runways/taxiways versus those of the satellite-textures. There is always a small difference at one side of the scenery when you get it matched/corrected at the other side. This is not very important for my personal use but bad quality and not good enough for common use, especially as the general texture-quality is pretty low. I am trying to develop some solution for that but whether it is possible for me or not, I don't know yet.If anyone has the same problems handling the big *.BMP I could extract a small program out my FLY!SatApp, which does this work I mentioned above on harddisk. Please ask me, I would mail it to you, would take a little time.I won't finish without thanking Roland and Harald for their hard work.RegardsGeorg HeliFLYer EDDW

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The thing is that I download the NIMA orthos (8 for a whole tile) in GeoTiff format. I have then the NIMA and the Landsat georeferenced.I use GlobalMapper to merge the 8 NIMA blocks (original projection is Geographic - WGS84 - ARC METERS). I change projection to "Geographic - WGS84 - ARC SECOND" to be able to export a specific zone in lat/lon coordinates (larger that a Fly! tile) in GeoTiff. Tips from Daniele Tona - thanks Daniele ;-)I reload this new file, change projection to "Geographic - WGS84 - ARC METERS" and export all datas to a new geotiff file.For the Landsat the original projection is "UTM - WGS84 - METERS", but you have to do the same reprojection and export with exactly the same coordinates.If you need to modify some pics before merging/exporting, you can use "GeoTiffExamine" to write back the geo information back in the file after editing ion PSP or PS.Then I (try to) optimize the 2 pictures in photoshop and merge them with layers functions. The base layer is the NIMA ortho, the landsat color is added in "color" fusion mode 100%. Then I duplicate it and insert the new landsat color layer in "filtered light" fusion mode (not sure of the translation) and play with the transparency to adjust the final result. (about 30-50% with NIMA orthos, and about 100% with Landsat B&W 15m orthos.

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Oups, you should read "Geographic - WGS84 - ARC DEGREES" instead of "Geographic - WGS84 - ARC METERS" of course :-roll :-eek

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Hi GeorgI have the same problems as you have with 30m and 15m Landsat ETM+ images. 10m SPOT images are only available for the west of Austria, but I live and fly in the east of Austria. With 15m I miss too many streets for VFR-Navigation using the ICAO-Chart.This is the reason why I also experiment with shapefiles.Maybe a combination of satelite images and streets from shapefiles are a solution.Its good to hear that you are developing programs to increase quality.And yes, I am interested in your program handling big bmp's.Thank you for your work.HaraldNB: My next idea is to write a DLL to change Radios via Keystrokes to use my (old) hardware for tuning radios. Its still a a long way, but a friend of mine is a professional C-programmer whom I can ask if I don't know how to proceed.

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Hi Roland,thank you very much for your explanation and help. Especially the Global Mapper Program was real new for me and I tried the older limited version you can download. It helped me really, when I played around a little with a LS7 GeoTIFF and different rasters I got an idea which could solve my problems with bad georefencing I get with my own program as I have no formula for the nonlinear WGS84 lat-lon projection. I could refenence over the WGS84 UTM m raster which seems to be linear and calc the lat-lons for the cuts by calculation from WGS84 UTM m to WGS84 lat-lon, seems I have got some formulas for that. Just an idea now, have to test it the next week. Thank you for the hint!I have another question about your Lyon scenery. There was no problem to install and FLY! the Paris and Clermont Ferrand sceneries, it was big fun.But I could not get your Lyon scenery to work, have two FLY! installations and put it there, but no luck.I started from Lyon Corbas, flew via Lyon Bron to Lyon Saint-Exupery - should your textures display in that area? Otherwise, which airports should I select or have I to delete anything from my FRANcE folder (tested to delete Rennes, no luck either) which has nearly all ROTW stuff?Thank you in advance for your reply.Best regards from BremenGeorg HeliFLYer

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Hi Harald,after working with Global Mapper I got a new idea how to solve the math problem with WGS84 lat-lon coordinates after cutting LS7 pics (see my reply to Roland). So give me some time to test the new idea, after that I will extract the helper tool for you (with or without the better math) and mail it to you - not sooner as next sunday as I have to work too many hours the next week at the job.I had the same idea as you to take these textures as a background, make a water-mask for the big rivers and seas (is pretty simple with these textures) AND paint some smaller streets and railway-lines on the "background". I think we could use Terrascene and shapefiles to create the picture with WHITE landuse-textures.It is already georeferenced and could be combined with the LS7 texture-file before slicing. I haven't come to that point until now due to those timeconsuming math problems but it should not be that big problem to code it. This could be great for your sceneries as you already created so many shapes by hand - and your sceneries look already really good, not so much need for LS7 textures. But maybe in other parts of Austria it would be a method do create only some shapes as an improvement for the satellite textures.I have got your eMail address already if it has not changed over the last 8 months.Have fun, may be some real-life night VFR flights after work? :-)RegardsGeorg HeliFLYer

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Hi Georg,GlobalMapper can also add some vector layers to the landsat pics. With Harald smoothing software and the PS like fusion layer capabilities of GlobalMapper, it could be a new solution without need of terrascene...For Lyon scenery : yes Lyon corbas is inside the covered area.If you have loaded the French South East elevations from Beralex ROTW (new SRTM or old one), then you have to remove in that dem scenery folder the related .scf and .pod file which are "visi D003164_nord.scf, visi D003164_sud.scf, D003164_nord.pod and D003164_nord.pod".Rmove also the same file for the D002164 tile (clermont-ferrand)- roland -

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Hi GeorgMy email is unchanged and take yourself whatever time you need to finish your helper tool.I really had some nice night VFR flights during the last month.This year I have already logged more then 160 flighthours, most on weekends as an instructor. So beside work, family anf flying there is not much time left for flightsimulation.RegardsHarald

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Hi Georg,TerraShape has a module for datum transformation in it.It was tested against commercial products and gives tne same results.It may be of some use to you.RegardsColin

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Hi Colin,this is a very valuable hint, if only for verifying own calculations. I tested it with conversion of LS7 lat-lon to UTM and it matched the LS7 *.met file values! I went the wrong way in the past when trying to find out the formula for pixel - lat-lon-values relation as it is a question of the rather complicated projection (ellipsoid). Am I right that the UTM coordinates are linear? Then I could have a relation between pixel and UTM coordinates and calc the lat-lon-coordinates afterwards. Could you give me the formulas for converting from LatLon to UTM (if not a secret)? I found the following way when searching the net ("WGS84 stdalone.pas")://Is this correct for converting WGS84 LatLon to UTM????// This is DELPHI, might be strange for a C++ guy!type vec3 = array[1..3] of real;conste1sqr = (a*a - b*:( / (a*a); {first numerical eccentricity}var Xllav, xr: vec3;...Xlla[1] := Xlla[1] * pi / 180.0; Xlla[2] :=Xlla[2] * pi / 180.0;{convert lat, ln, alt to ECEF X, Y, Z}//xlla input, xr outputLLA2XYZ(Xlla,Xr);...procedure LLA2XYZ(Xi : vec3; {lat [rad], lon [rad] alt [m]} var Xo : vec3); {ECEF X [m], Y [m] , Z[m]}{this procedure converts WGS-84 Lat, Lon and Alt [above ellipsoid] to ECEF XYZ}var N: real;begin N := a / sqrt(1.0 - e1sqr * sin(Xi[1]) * sin(Xi[1])); Xo[1] := (N + Xi[3]) * cos(Xi[1]) * cos(Xi[2]); Xo[2] := (N + Xi[3]) * cos(Xi[1]) * sin(Xi[2]); Xo[3] := (N * (1.0 - e1sqr) + Xi[3]) * sin(Xi[1]);end; {procedure LLA2XYZ}This is just one way, I found some formula for converting back but have not yet programmed and tested it as the idea is brand new for me to use UTM for georeferencing of the LS7 pictures.RegardsGeorg HeliFLYer EDDW

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Salut Roland,thank you for your help.Switching out visiD003164 (have NOT _nord and _sud, may be an older version, have to update from ROTW!) showed your excellent scenery. When FLY!ing with the helo I discovered that wonderful small airport in the hills "Tarante". MUST do a fixed wing flight from Lyon Bron to this AP, this landscape, the river, the hills - is like a little holiday!If you were a fee a would ask you to put in some (generic) objects as landmarks or just for the eyes - but your scenery work is great enought without that. Thank you for your hard work, merci beaucoup!!!I own only the (reduced) free version of global mapper, don't think they activated these special vector layer functions!RegardsGeorg HeliFLYer EDDW

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