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Guest JohnC

Google Eath and photo scenery

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I am wondering if anyone has compiled a tutorial on creating photoscenery from google earth for FSX. I have been keen to create my own photoscenery for a while but now that FSX supports such great resolution I was going to try and start my own project. Anyone got any ideas where to start. I have looked in the beginners post but there isn't much info on FSX and I am not sure what stuff still applies to the FSX SDK? Any pointers or help appreciated..CheersSteve

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Hello Steve,Sorry, we'll get around to a new FSX Beginner's Guide as soon as I get over the Christmas hangovers (some parties!).In the meantime, Bob Bernstein is our expert on custom ground and hopefully he will step in and provide guidance.Best regards.Luis

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Thanks Luis, looking forward to some input from Bob..Steve>Hello Steve,>>Sorry, we'll get around to a new FSX Beginner's Guide as soon>as I get over the Christmas hangovers (some parties!).>>In the meantime, Bob Bernstein is our expert on custom ground>and hopefully he will step in and provide guidance.>>>Best regards.>>Luis

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Hi all, Steve, the steps to create custom ground involves capturing and manipulating your imagry, and then compiling into bgl.I don't use Google Earth for anything, so I'm no expert with their images. But I imagine them to be simply an image source, so generically, you capture the image however you can, preferrably downloading the image in a way that captures its metadata and preserves its resolution...metadata reports the files geographic boundaries, and its projection.If your image downloads in "geographic" projection, perhaps it will be called "geodetic", and if your image references wgs84 datum, then you will be already set to go. If not, you need to convert the projection and datum. I can't explain the conversion process here using freeware tools, I've become spoiled. I bought a license of Global Mapper for that, which is a commercial gis tool. (about $250). There was at one time a great avsim thread on using freeware tools, search the forum for that thread).Once you have your image in the correct projection, and know the geographic boundaries, you create a text file called the inf file. This can be done in any text editor, including notepad.Review the fsx terrain sdk. There are explanations of the inf file structure and you can do some cut and paste to shortcut your first effort. You'll of course need the tools for compiling your inf also from the sdk, resample.exe primarily.work on these steps and get back on the forum with questions, that's imho the best way to learn this stuff....try some things and discuss what went wrong.You'll see discussion in the sdk about water/land masks and blend layers, this is some of the fun part, but I suggest you master the steps to get a basic layer to display and get comfortable one step at a time.Enjoy!B

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Hi Bob, thanks for the notes and helpful comment. Basically what I am planning to do is just use google earth to capture screenshots of a small area I want converted. So I will need to stitch some shots together in photoshop before converting them. I'm not sure if I can download the file with meta data but I can get a grid ref of particular points through google earth. This is probably the thing I find most confusing how to sort out grid refs etc. as I think I read that FS has a different type of ref is that correct? I am assuming that these images are also ortho corrected because google overlays a map on the arial imagary? The projection thing I am unsure about?I will have a look at the SDK a bit further. It's a little confusing to a newbie like myself. I will maybe post my first efforts here.ThanksSteve

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I'll be on travel til Friday, I'll check in then. I'm sure others on this board know google earth better than I do, and could advise you on projection issues.Best of luck,Bob

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Hi Luis, thanks for that! This looks real interesting. I managed, before I read your post, to add a chunck of photoscenery into FSX. The coordinates were out by about 20 miles long and around 1 lat. I am assuming this is to do with the difference in coord system between fsx and google. The other thing I noticed was the image had been stretched? A projection issue I suspect..Still learning here but I was glad I actually managed to get something into FSX. I notice this program SBuilder for FSX looks good... will have to try that this evening..Thanks for your help, it is much appreciated..Steve

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Hi Steve,The images from GE Maps use the Mercator projection while FS uses the geographic (latlon) projection. This means that there will be a misalignement in the NS direction. If you make a photoscenery of, say 1 tile extent in the NS direction, there will be almost no distortion. But if you span many tiles in the NS direction, say 1 degree of latitude, there will be some distortion in the center (not on the north and south borders if your inf and picture are correctly implemented). This distortion becomes worst as you approach the poles.Therefore I would certainly divide your photo project in many "horizontal strips" to avoid projection issues.Regards, Luis

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Hi Luis,Thanks for your helpful comments, will bear this in mind. Does SBuilder produce corrected scenery?When you say 1 tile are you speaking about the grid on the mercator projection that is shown in the GE app?Steve

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Hello,SBuilder for FS2004 can produce photoscenery (the link that I passed to you helps on that task). It places the photoscenery as VTP polygons. So you can put other VTP items (polygons or lines/roads) on top of the scenery. You can also place autogen on top of the photo scenery.If you use the Resample tool you can not do that. But the "VTP method" has a problem - the alignement of the VTP photo squares is not perfect on some views and, some times you see small gaps. If you search this forum with the keywords: "VTP" and "gaps" you should get more information on this.A tile is the minimal rectangle that you can cover with photoscenery. It is about 1.2 km by 1.2 km at my home latitude (40 N). If you install SBuilder you can see this tile grid by chosing LOD13 (SBuilder 206) or QMID15 (SBuilder for FSX).Note that SBuilder for FSX can not (yet) place photo scenery. If I had a permission by "Live Earth" to use their image servers, Sbuilder could make the photoscenery in 2 or 3 clicks. Kind Regards, Luis

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Hi Luis,Ok, I'm beginning to get a picture in my mind of what is and what is not possible. Is it better to use live earth images rather than google earth or are they just the same in terms of projection?Sorry for all the questions, really want to nail this one.. if i can:-) Steve

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Hi,The projections are the same (Mercator). The coverage is different and, probably, GE is better. I only referred to LE because I do not think that GE would allow me to release a freeware tool to transform their photos into BGL sceneries. Because LE and FS come from the same company, may be they could agree. But this is just my wish :-)Luis

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Hi Steve....a few hints in using GE......1. Make sure terrain is unchecked in your primary database layers and set terrain quality to highest in options.2. Set your altitude to 2000 feet by trial and error back and forth and once you get there place a placemark there called alt2000.3. Make the yellow pushpin placemark and its label 100% transparent. Now you can return to 2000 feet quickly from now on by clicking on the placemark in your list of places..4. After picture is downloaded and sharp capture image to clipboard by pressing Alt-CTRL-C.5. Switch to Photoshop and store the image.6. Scroll and repeat 4 and 5 until you have about 300 megs if your ram is 1 g. Use the SDK to guide you with using resample.7. Last time I looked in the google forum GeoTiff was not available without huge investment in Google Earth Pro and other support software.8. That is not a problem because you can determine the extents of the pixel in the NW corner of your image, and your pixel size in degrees very easily and place them in resample.Good luck. Using this method I can see rows of headstones in a graveyard, individiual shrubs and the grass between sidewalks and street. Incredible. Long horizontal strips are a real good idea if you have large excursions NS. Google will be very unhappy if you distribute their images.

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What I have done is to use a utility (such is common in graphics software) to determine accurately screen pixels / inch for my display and resolution. Then, assuming I want 4.8 m/pixel scenery I just compute the distance of meters per 1 inch of screen space. you could also do it for 2.4 or 1.2m. for example 96 pixels / inch x 4.8m/pixel or 460m / inch. In GE (I'm still on ver 3) then use the measure tool to create a 460 m line. Use a ruler and zoom in/out until the line measures exactly 1" on the screen. This should minimize the amount of resampling required of your source data. I use GIS software, so I take a capture with the lat/long grid on and off. Using the grid I georeference the image, then just substitute the identical dimension image without the grid.Once I have my image I create 2 copies or layers in graphics software and go over the copies as necessary to create the blend and watermask images. I send all 3 to resample, plus any night time or winter variations.I think it might be better to set specific output resolutions desired rather than using the default "all". Also try using compression of 90 and see if that helps filesize. right now I am experimenting with 1.2 resolution source data and setting the output LOD to 13,15 to create 4.8, 2.4, and 1.2 m resolution variants. I'm also wondering about total file size and I have been experimenting with the SplitFileLOD to create LOD13 tiles, like in FS9.scott s..

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