# .inf Parameters

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I've been re-reading through the terrain SDK 2002 and I'm beginning to get a hand of things...Anyone kind enough to explain the following parameters in some humane manner as described in the FS2002 SDK for Mt. Rainier, Washington State area!?Lat = 46.99916666667Lon = -121.9466666667NumOfCellsPerLine = 457NumOfLines = 375CellXdimensionDeg = 0.0008333333333333CellYdimensionDeg = 0.0008333333333332CheersStorm

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Hi Storm, I'm a bit busy today, but if you check my website you may find some useful information. And maybe generate a few more questions! Stevewww.fs-traveler.com

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Hi Storm.Lat = 46.99916666667Lon = -121.9466666667These are your NW corner posistion.--------------------------------------NumOfCellsPerLine = 457NumOfLines = 375These are the actually the verticies X,Y ( 457,375 ). This is the matrix of your data. These are misnamed by Microsoft... they should be called NumOfVerticiesPerLine and NumOfLines. This mis-naming has caused lots of grief for designers.--------------------------------------CellXdimensionDeg = 0.0008333333333333CellYdimensionDeg = 0.0008333333333332This is the distance between the verticies in degrees ( the actual cell span ).The formula is :Lonspan = longitude span in degreesLatspan = latitude span in degrees CellXdimensionDeg = ( Longspan / ( NumOfCellsPerLine - 1 ))CellYdimensionDeg = ( Latspan / ( NumOfCellsPerLine - 1 ))Why is it -1? Because the number of enclosed cells is always 1 less than the number of verticies that enclose them.This is the data resample needs to define the source.Dick

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Cheers Dick, once again...However I'm still at a loss. I've been searching the net for some decent tutorial to explain the creation of DEMs (playing around with grey-scale contours and saving image as .raw..) but can't find any. That aside, the .inf file seems 'easy' to create but I still can't figure out (or rather, am not certain) how to obtain the values I pointed out... Probably I'm threading on one of the hardest aspects of scenery design, dunno.Storm

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Hi Storm.Why not go to Martin Wright's website, and look for fstrn. It has the ability to edit dems before mesh creaion, in a paint program. It also has the ability to merge gotopo30 data to SRTM data, to fill the holes in the raw data.It might help if you tell us what area and extents of lat-long you want to mesh... we could then point you to a suitable source of data.Creating mesh from existing sources of data is pretty automatic.Dick

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Dick,I'm currently modifying the coastline of the Maltese Islands (Malta), for starters. In fact the default Island of Malta is a tad smaller than how it should be.The default elevations...well, they leave much to be desired - hence the reason why I'd like to get into creating good terrain.I'd be grateful if you can point me to good DEMs of Malta and a good source (+ reference) with which to create the terrain.CheersStorm

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Hi Storm.Bad news. I don't believe there will be much in the way of elevation data for those islands ( at least not for free ). SRTM data will eventually become available, but not for perhaps many months.For now, Gotpo30 data or GLOBE data is about as good as it gets... and both have a resolution of about 1km... same as the default scenery. You could make mesh of LOD7 with this, which is a bit oversampled. Check out this post:http://forums.avsim.com/dcboard.php?az=sho...sg_id=918&page=Here, Sergio was able to use a spreadsheet to alter elevational data. It would not be impossible to do this... but Martin Wright FSTRN is probably a good way to go in altering elevation in the data.The easiest solution might just be to wait until the raw SRTM data becomes available to the general public. ( you could beg for the SRTM data: http://www.jpl.nasa.gov/srtm/questionnaire.html ).Dick

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This is getting a bit complicated Dick!I'm really making a huge effort to try to understand all the jargon and stuff :-walksmileSo, let me try and summarise what I've gathered up until now...-> To simulate accurate terrain one should opt to use DEMs rather than play around with Ground2k's re-mesh function..correct? Question: Then, what's the difference between the two methods?-> No DEMs for the Maltese Islands, or at least none having a better resolution than 1Km. Question: If I obtain survey maps of the Islands, can I create a grey-scale DEM myself as outlined in the Grises tutorial?-> Having created the DEMs, creating the .bgl file is a matter of following the MR SDK tutorial and filling in the blanks? I downloaded FSTerrain but then again, I'm new to all this and I love learning through example - FSTerrain documentation is limited in this sorry to say.I'll stop here for now heheh. Anyways hope you can provide me with some answers Dick, or anyone else for that matter! Just one thing -I'd be grateful if you do not assume that I do know what things mean at least with regards to the mesh discussion. :-beerchugCheers lads.Storm

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Hi Storm.There is a big difference between the flattens made with Ground2K ( or SCASM's Area16n ) and mesh. Mesh is the elevation upon which the terrain lies. The flattens of Ground2K ( invisible lwm masks with elevation ), and Area16n flattens, both intercept the mesh, and raise or lower a polygon of ground terrain.You could try to remesh the island with flattens, but I suspect it will be difficult with such a large area. The idea of remeshing was created to handle the residual flattening of changed coastlines... we can reshape the water and land, move the beaches, but the flattening of the default FS water remain. Mesh cannot overcome this, but we can re-intercept with new flattens at new elevations. The process is crude.To re-do an entire island requires the creation of new mesh ( although flattens might still be needed at the coasts ).I don't think this bug regarding original water flattening has changed for 2004.==============Another approach might be to use FSMesh, by Burkhard Renk... his forum:http://forums.simflight.com/viewforum.php?f=26FSMesh allows the creation/alteration of DEM data.... you can get info from topographic maps, etc... and make DEMs. FSMesh is commercial, and is sold at simmarket.com ( about 23 euros ). This isn't flattening, but actually adds or alters mesh elevation points.===============One of the best sources for info is Steve Greenwood's website:http://fs-traveler.com/fs-traveler.htmlDick

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Dick,I'm trying to raise the coastline terrain using flattens (re-mesh in Ground2k)...I'd like to know what the difference is between chosing LOD12 or 11 etc. I tried all the different types (LOD8 to 12) but it seems the result is unchanged. Can you shine some light on the difference in this respect?Storm

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Hi Storm.In Ground2K, choosing the different LOD levels should change the spacing between the remesh points. This is Christian's code and he would be the best to comment on it... you could e-mail him. Christian does make remesh like this: LWMPoly2 2,0,1,296,0 LWMPoint 121,233 LWMPoint 121,2332 points, but they are the same point! So a single LOD13 point is acting like a tent pole, propping up the mesh.As mentioned before, there is a line in the sim's "FS2002.CFG" file:TERRAIN_MAX_VERTEX_LEVEL=19That value could be changed to 20 or 21, and it will have an effect on how mesh, and remesh is displayed. The default 19 will show remesh as a more rounded look ( allowing a lower LOD to achieve a rounded look ).There may be issues with FPS, mesh "popping", etc... with 21. Steve Greenwood has probably looked at this more than anyone else, and he might better explain the effects of that change.That change will affect how Ground2K's LWM remeshing appears.Also, the underlying mesh LOD also seems to affect the appearance of the remesh... so if your mesh is at LOD5 or 6, and your TERRAIN_MAX_VERTEX_LEVEL=19, then the remesh LODs might all look the same.=========================Remeshing can also be done with LWM land polygons with defined elevations. You could actually trace the topographic lines of a map in Ground2K, layerint the elevations like a cake.Remeshing can also be done by the older Area16n polygonal code.Dick

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Dick,The discussion is ongoing it seems :)Anyway...I've been playing around with the terrain-max value parameter and have noticed (could be just an impression) that the lower the value, as you say, the smoother the elevations, or rather the lower is the inclination gradient. On the other hand, I replaced the value with 30 (nothing wrong in experimenting!) and the inclination gradient increased drastically - the 'drop' is near vertical. The advantage I see from increasing the value is that the elevations are more predictable. With lower values my elevations tend to be short of where they should be. The disadvantage of such an increase as I see it, is the 'tent' like formation as you correctly outlined.Storm

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