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rhumbaflappy

perfect elevated lakes

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hi, I have stumbled onto a way to make perfect lakes on elevated terrain. I covered this area in 1 arc second SRTM mesh and redrew most of the shoreline near PAKT ketchikan Alaska. Since pics dont last long, ill try to explain it. This area has lakes at all different elevations from 30m to 800m. They are usually crammed into a mountain valley, and just drawing them in G2k4 and praying was not working. I would get sharp cliffs if it wasnt perfectly aligned with my mesh.so I came up with this idea. If i make a flat plane it would act as the water level and i could see where the shoreline belongs. I slew my plane to the spot i want my lake and write down the Co-ords. Using FSconnect and G2k i use my map to get me close. http://forums.avsim.net/user_files/57614.jpg open gmax and make a plane 20k x 20k feet and export. write in my co-ords http://forums.avsim.net/user_files/57615.jpg now i slew out to my spot and look down -Control+S- It now shows a rough outline of where the lake should be. http://forums.avsim.net/user_files/57616.jpg I use the FSconnect feature to draw a rough outline of my lakeshore and then go back and draw a more accurate version. http://forums.avsim.net/user_files/57617.jpg now i got back and slew down till im touching the gmax poly and that will tell me how high to place my lake. All thats left is to delete my gmax poly and then a fly by. http://forums.avsim.net/user_files/57618.jpgthis is so much fun! now my lakes are accurate (for my mesh) and they look like they belong, and you can pick em out from a VFR chart.hope this helps someone in the same situation. This lake wasnt the best example, but previous lakes showed a perfectly defined shoreline that was easy to follow.joe

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This looks pretty fabulous, Joe. Congratulations! Flying in that area will finally start to look like the real thing.Best regards.Luis

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Joe, I am totally blown away! I have been following the discussion on the BFU forum with great interest. PAKT is my virtual home, so along with Mike and others, I am anxiously awaiting the release of your work there :-) I had a couple of cabins on Ketchikan Lake that will now need to be happily re-done!!!Thanks for all your effort on this Joe, I very much appreciate it :-)

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Hi Joe.What's off is not Ground2k, or the SRTM mesh, but the map you use for Ground2K. It doesn't have the right projection/datum ( geographic/WGS84 ).But, the method you are using is great! It "slices" the mesh with the poly, and reveals what must be the shape of the lake ( assuming it is level ). That's a great approach, and looks great as well. It solves a problem for G2K users that cannot find or reproject maps to the right projection/datum.Dick

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thanks guys, I'm still kinda feeling my way through all this. It's a lot to take in when you combine it all together. Dick, I used a WGS84 topographic map, but in order to get the detail I wanted to see, I combined many pieces into one bitmap, throwing the accuracy slightly off im sure. My biggest problem is finding accurate maps large and clear enough to work with. Alaska seems to be especially difficult. I found it strange that my shorelines seemed to be dead on, but my lakes were slightly off. I have adjusted my approach after reading up on TMFcalc and using the Cell Grid to pin point my area of work. Those tools are a great help. The gmax poly method is nothing more than a 'cheat' Hopefully by the time i run through this a few more times I will get more accurate.thanks again, Stop in at BFU if anyone's interested in the progress of the Ketchikan Burrough.joe

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I bet the lil'Woman is hating this new program! LOLLooks great bro!!What is exciting for me, is that the way this is going, this will be the definative ketchikan, along with your mesh, so it will be a little easier to design for without worring if your scenery will work with whatver mesh someone decides to use to make the area look better.I have a scenery coming out and one of the strips in on a mountaintop and has a sceneic lookout, well I tried it with 3 different freeware meshs and got different results with all 3....went with the default!Regards, MichaelKDFWhttp://mysite.verizon.net/res052cd/mybannercva1.jpgCalVirAir International VACougar Mountain Helicopters & Aviation[link:www.cgrmthelos.com]Cougar Mountain Helicopters

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Hi Joe.The maps can be WGS84... that is the datum. But topographic maps are generally in othographic projection, or Lambert conical, or some other 'measurement-based' projection. Geographic projection is based strictly on degrees of lat-long. LWMviewer bitmaps and TMFViewer screenshots are examples of geographic projection.Dick

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