New European Freeware terrain meshes

[rhumbaflappy 113]

John,Yes, we try to use the same approach as Baz..."Well, the most realistic scenery I have and still use on FS2002 is Orlando Sotomeyer's Glacier National Park for FS2000. This was free and the readme contained loads of technical data and source material info."Did you miss that part of his post? Really, what were your sources of technical data other than the easily obtained Gtopo30 DEMs?

[Guest]

rhumbaflappyI don't think there's much point going over the same ground again - I think we've already covered these points so we'll have to agree to disagree on this occasion.JohnVisual Flighthttp://www.visualflight.co.uk/

[nudata 10]

You will probably evenyually find that the sources are easily available and conventional. If the "secret" were in the sources we will not know what they are. If the "secret" is in the process the sources would be revealed. Probably just a lot of scanning and Photoshop work and for that they derserve some money. However, those that pay derserve to know if this is LOD n accuracy or LOD n-x oversampled!! Without this data only the locals will ever be able to assess the value of their expenditure.Dick

[Guest]

How many UK meshes could one sell for $20, if the DEM produced was accurate to 10 metres?I have the Data, it's converting to DEM that would take time.orDo we all wait till NASA/JPL releases the new data supposedly later this year!

[Guest]

DickIt would help if there were a level playing field, but unfortunately there's been so much potentially misleading quotation of LOD and horizontal resolution that anyone coming onto the scene and stating source data resolution rather than resampling interval is likely to find themselves at a disadvantage.For example, the latest European freeware mesh claims to have a resolution of 3.75 arc-seconds and LOD 10. Does that really best describe the quality of the mesh (LOD 10 = 38.2m), or should the source resolution be quoted instead? (I'm assuming this isn't the source resolution, but it doesn't actually say).The trouble is that these potentially misleading descriptions are already out there. It might be all very well for people with the background knowledge to make informed judgements and say aha yes, that obviously refers to the resampling level, not the source data, but the wider flightsimming community aren't going to know that, and if they make their downloading/purchasing decisions based on claimed LOD/resolution they might end up making the wrong choice.Some of you are saying that it's valuable to know this information, and yes, I'd agree it is in an ideal world, but unfortunately that's not what we've got. We've got a legacy of potentially misleading descriptions, and that situation is continuing into the present and will probably continue into the future (though as I've pointed out before, the situation is different in those parts of the world for which high resolution source data is freely available).Against this background, I thought it best to help people decide by providing two reasonably sized demo areas rather than providing potentially misleading specifications. However it seems some people prefer not to do this. I can't help wondering if these are the same people who might choose not use the listening room in the Hi-Fi shop as long as the specifications look OK...I admit there's a problem for those people who aren't themselves familiar with the landscape. This is a difficult one. I'd suggest reading the testimonials on the web site but this is unlikely to convince those of a more skeptical disposition.I'm not sure what the answer is, but I don't think quoting the specifications of the source data sets really helps, particularly when the processing algorithms make so much more of them, and some of them are not based on a regular grid in any case.JohnVisual Flighthttp://www.visualflight.co.uk/

[Guest christian]

Do you really have the data? Then it's better to go ahead processing it and don't wait for SRTM data. Your dataset will be more accurate. But it is a very big job. And you need some geoprocessing software like ArcGIS 3D Analyst...Cheers, Christian

[Guest]

Are there any 3.75 arc second DEMs out there? I haven't seen one and I have looked all over trying to solve this puzzle. Still I see the claims for such source data for terrain mesh files created for different parts of the world by both freeware and commercial outfits.Folks who claim that their source data are 3.75 arc seconds must be either: 1. creating their own DEMs from scratch or 2. post-processing lower resolution DEMs (e.g. 30 arc second) using some interpolation formula that increases the number of cells but can't really add resolution. Further claims that the interpolated cells are then manually fixed don't say much for accuracy, as the original points were from low resolution data and their accuracy is not increased by just tweaking the added points. Bottom line, you really have to start from scratch if you want to be accurate.On the other hand there's no excuse for not disclosing the original source data resolution. There's a 90% chance that it is 30 arc second data if it is for a region outside of the USA. However, if you are building DEMs from scratch, like the Spain Mesh Group (freeware http://www.simuvuelo.org/pags06/smg.htm ), you should be able to say so (with some pride since this is hard work) and describe the resolution of the DEM you are creating, the method used, including maps used, and the LOD you are using to compile the BGL. These folks are really setting an example of improving the scenery for their country where the official DEM sources are not adequate or affordable.

[Guest]

The work of the Spain Mesh Group is excellent, and I'd personally recommend it to anyone wanting high quality mesh scenery for that part of the world (although coverage is not yet complete). They are fortunate in having official permission to use the Digital Military Map of Spain, though I appreciate they have had to use considerable effort and ingenuity to make use of the data.In this country (UK), the situation is completely different. The Ordnance Survey are apparently very keen on enforcing their copyright, and this specifically prohibit what they call "redrawing" which includes converting the data into the form of a digital map (e.g. a DEM). So while I wholeheartedly join you in applauding SMG's efforts, I don't see that this sets any example for other countries without free or affordable access to even this sort of data.JohnVisual Flighthttp://www.visualflight.co.uk/

[Guest]

Why don't they just say 100 metres or whatever between each elevation point.Right John, Then it's my method! The one with teams of people with GPS units going to the tops of every hill!Just how would the Ordnance Survey know? Unless they deliberatly put in false data, and that is usually done with roads, rivers & rail roads not contour lines.

[Guest]

HiWhen I tried VISUAL FLIGHT Scenery I found that it reprsented my design area very accurately. I have three airfields in a small triangle at the foot of the North Cotswolds, UK.The locations of these airfields are at different altitudes and I was able to place my airfields level with the Visual Flight Terrain.I could not improve the VF scenery for my area and now concentrateon adding buildings, etc.If you bought your computer from evesham.com then you will see their building on my website.ngowww.users.globalnet.co.uk/~ngo

[Guest]

I never read so much rubbish - in this forum ever before!!Raimondo

[Guest]

Very Interesting Thread, I had tried flying around in the Lake District and have made an Adventure. I have tried it out on all the mesh sceneries and have made a comparison. All of them had problems but I would have accepted anyones except the Haut's Mesh (and I wanted it to work because it was free and he was giving us all of europe so i am still thankful to Haut.). I actually set up where you can fly off the top of Scafell Pike and soar down into the valleys in an ultralight. Also flying from one lake to another in the pontoon version is loads of fun. (I used to visit those places in my old MG Magnet Saloon - It was a wonder I made it up them passes.) But, the one that I have left connected up is Visual Flights. and Gaia coming next. Obviously, my choice is the one that seems to look most like the lake district to me. But i have to say that Haut's was really poor for viewing the Lake District as lots of montains and valleys were not even there for some reason. Bowfell,the 2nd highest mountain in England was just a pasture.So, what is one suppose to do when making scenery? I ended up turning all the mesh off and creating it for the default scenery. I don't think i want to tell everyone that they got to go out and buy this or that mesh scenery to run my adventure. Then, personally, I turned on the VF scenery. Anyway, thanks to everyone who making mesh scenery, I am the first one trying it out. Cheers

[Guest]

Hi:First of all, as one of the Foundation Member of Spain thanks to John and Orlando for the kinds words about our works. We really appreciate the interest of our work even out of our geographical area.In fact, we are only initially 4 people worry about the infamious mesh terrain we have in Spain for FS. Our country has fantastics mountains, canyons, valleis and nothing appear in defaul scenery. Even they didn't appear in "suposse to be" detailed mesh (even payware) because all of then are from same base data, procession by interpolatin procedures. They add details, but "non true" details.John said:---------------------------------------------------------------though I appreciate they have had to use considerable effort and ingenuity to make use of the data.----------------------------------------------------------------:-) I hope this was a kind comment (my english is not really good). We develop a procedure using tools provided by the map. In fact, we don't extract data from the encripted original database, we only can obtain a visual hypsometric map (each elevation represented by an only color), and then process this graphic file to obtain a .dem file. When know, the process is easy and fast. In fact, our main problem was the diferent map projection (UTM on the map, geographical coordinates in FS), and we solve it working with a freeware GIS (GRASS) and late developping our own utility to re-project the map.From the beginnig, our idea was not obtain a whole spanish coverage. In fact, we prefer to document all our process and share it with all the comunity, because we think that the best for develope and acurate mesh is knowing the area. At the end, more people are developping mesh scenerys with our method.I thinks our method can be applied with another sources of data, if the digital map has the ability to obtain hypsometric maps "painting" the elevation points whit pre-defined colors, and I am not sure that it can be in problems about copyright, because you are using a tool provided by the map. Of course, if your scenerys are freeware, I think the problems probability tends to 0. But I don't know laws and conditions of anoother countries.Well, this is the complete story. If you want to have some feedback of information (all our documentation is in spanish, sorry), fell free to contact me.See youH

[Guest]

>John said: >--------------------------------------------------------------- >though I appreciate they have had to use considerable effort >and ingenuity to make use of the data. >---------------------------------------------------------------- >> :-) I hope this was a kind comment (my english is not really >good). Yes, definitely a kind comment. :-) JohnVisual Flighthttp://www.visualflight.co.uk