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Guest pks1414

Groan...another Ground2K question

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Slowly but surely I am getting there however I am obviously doing something wrong. I enter the coordinates for the area that I want to work on (I actually want to add a missing road by an Airfield I have just added and add a small village)When the working map comes up my airfield is there...great. I add my road where it runs, compile. When I look in FS9 the road is nowhere near where I have put it ( at least its there which is a major step forward for me :) ) Anyone got an Idea what the heck I am doing wrongThanksPaul

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Hello Paul,unfortunately I have no solid answer to your problem, but maybe a hint into a direction.FS uses internally a WGS84-based coordinate system (the same as in GPS systems), which is different from the coordinate system used by topographical maps. All points in an area differ by a certain N/E offset (each topographical map tells the offset for a particular area).Could this be the explanation for your trouble?My theoretical knowledge about this topic is rather thin. Maybe someone else can jump in here?Cheers,Edgar

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Sounds like the coordinates of your map in Ground2k are not setup correct. If these are off, the roads in FS will also be off of course.

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Its odd because the road is there but as a guess I would say about 800 metres off target

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Hello Paul, Perhaps you could help us by providing more information concerning your problem.What are you using as a background image - a screenshot of Flight Simulator, an aerial photo, or a map? This can give quite different results, and the easiest and most accurate image to use is probably a screenshot.What precisely are the coordinates of the NW and SE corners as you enter them in Ground2K4? Many times, people either enter the wrong coordinates or in the wrong format.Best regards.Luis

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Hi Luis,I daresay I went about this the wrong way completely. I used cellgrid2004 first of all, then in FS9 I took a top down view. I then did a slew to the top left and bottom right corners of the area that I wanted to work in. I did notice that the 'higher up' I went the angle of the cells automatically went square to the screen and I had a green line running top to bottom. Once I had the coordinates I removed the cellgrid and took a screen shot from the top down view again, making sure my airfield was still in the shot.It is this bitmap that I used in Ground2K. I am at work at the moment but when I get back I will post a screen shot.This is the first time that I have really made an attempt at using Ground2k, I wanted to add missing roads and try and put the river right in Evesham (UK not New Jersey)I would not be at all surprised if I have got this wrong :) I am definately a candidate for the complete tossers guide. I eventually got my head round the basics of Gmax so there is hope for me...just takes a bit longer :-hah

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Maybe install FSConnect.dll, and then fire up both FS9 and your project, slew to where the road is showing in FS9 and then look at your project and see where the crosshairs are showing?scott s..

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Hello Paul,forgive me a question; The sqreenshoot you use for the G2K-background is N/S directed, e.g. you pressed SPACE in Slew-mode to turn the aircraft into north? If so, I see no problem to read the correct coordinates for the NW/SE corners. As a proof of concept you could use a screenshot with cellgrid lines. They should be identical to the cell lines drawed by G2k.My suggestion about WGS84/topographical conversion is here not necessary, because you already use WGS84 data here.Regards,Edgar

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Aaaah, no I didn't press SPACE, I moved the plane to the centre of the runway that was all, that heading is 246, is that going to have something to do with it?. Should the plane always be facing North?ThanksPaul

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Hi Paul,the background bitmap for Ground2k must indeed face north, like a topographical map.Cheers,Edgar

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>Hello Paul,>unfortunately I have no solid answer to your problem, but>maybe a hint into a direction.>FS uses internally a WGS84-based coordinate system (the same>as in GPS systems), which is different from the coordinate>system used by topographical maps. I think the current USGS topos (1:24000 DRG) are projectedto UTM using North American Datum 83 (NAD83) which I don'tthink has any significant (at least to FS anyway) differencesfrom WGS84. The TIGER 2000 data should be OK too.scott s..

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Hi Scott,it's true that NAD83 and WGS84 are virtually the same datum (i.e., the parameters that approximate the shape of the Earth) but there's a big difference between the FS-native lat/long coordinate system and the UTM projection used for many topographic maps, orthophotos, satellite imagery, and digital elevation data. See John Child's introduction to the topic here: http://www.terrainmap.com/rm1.htmlWhen using UTM coordinates in FS the horizontal offset is about 50 to 300m, depending where you are on the planet. For some smaller projects that's not a big issue but for larger areas a non-linear distortion (rotation plus stretch) will also come into play, which makes it necessary to re-project the source data to lat/long before using them in the design process. Fortunately, with ERDAS ViewFinder we now have a freeware utility that does this for us. See the recent thread in this forum.Cheers, Holger

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Back again, really confused now. I started all over again by getting the cell grid which is 380,107. Created a BGL and added to the scenery (pic attached. I then did a slew with the plane to the centre of the runway and pressed SPACE to get North, did a top down view and took a print to use as my background Map. Blow me, put all my coordinates in(I used a cross section off some of the cells to get NW/SE) and fired up, map comes out okay but when I load up FSP and use the connexion I am miles out and the odd thing is the cells on Ground2k go across whilst the cells created in FS9 using cellgrid go up :-hmmm Can I be a real pain and have someone do me a simple step by step, I am lost as to why it wont work. Getting the road into FS9, but in the wrong placeThanksPaul

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Thanks. I see now that the resampler needs data that are equally-spaced angularly (is that a word?), that is, unprojected. Though in my area of immediate interest (Hawaii) it might not be that big a deal. At any rate the data I really need are in shape files UTM projection NAD83 datum so I will get the ERDAS tool and between that and forest GIS should be able to get a .bmp resampled to unprojected WGS84.As an aside, is there any shape file for FS cell grids? I made sone by hand (point and click on the map) for Hawaii in fGIS, but it isn't accurate nor easy.scott s..

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