Re: [Flightgear-devel] High priority: fixing the Great Lakes in
David Megginson wrote: [...] I think someone originally had a grandiose plan to build a water network, and wanted eventually to model locks, rapids, waterfalls, etc. to account for changes in water surface elevation, but that never happened, and to be honest, we should never have let the code into production until it worked. Haha, I guess that's been me. My plan was to use river locks and waterfalls to logically disconnect the Great Lakes area from the Atlantic Ocean, not via yet another hack in the code but instead at data level. It's still on my TODO list (anyone !?), but the actual issue is a totally different one - see below. [...] Is there anything else we can do to address this problem? Were we forced into this because of different GIS datasets? Exactly. I'm pretty certain that we never had the Great Lakes region at a reasonable elevation from an unmodified VMap0 dataset using the political boundaries as landmass - at least according to the old 'src/Prep/TGVPF/process.sh' script. The reason is simple: VMap0 defines the Great Lakes as not being covered by any political boundary - therefore it's being treated as ocean. In the meantime we've made a polygon set to seamlessly fill The Great Lakes Void - which is likely going to address the issue you've mentioned. But there are still a few other places which are presumably affected by the same cause (Caspian Sea, I guess, and probably the Dead sea as well mmmh, maybe we've already fixed these as well). Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High priority: fixing the Great Lakes in
On Sun, Mar 28, 2010 at 1:58 PM, Martin Spott martin.sp...@mgras.net wrote: In the meantime we've made a polygon set to seamlessly fill The Great Lakes Void - which is likely going to address the issue you've mentioned. But there are still a few other places which are presumably affected by the same cause (Caspian Sea, I guess, and probably the Dead sea as well  mmmh, maybe we've already fixed these as well). That's great news -- thanks, Martin! I'll look forward to the new scenery. Right now, I can't bring myself to practice approaches at waterfront airports, with the giant cliffs all around them. All the best, David -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High Priority: fixing the Great Lakes...
On Sunday 2010-03-28 David Megginson wrote: Now, quite a few years later, the Great Lakes are still broken in our default scenery, and as a result, FlightGear looks ridiculous to any new user who comes and tries flying in near cities such as Toronto, Rochester, Buffalo, Cleveland, Detroit, Chicago, or Milwaukee. Sometimes pictures really *are* worth a thousand words. I think this is one of those times. I've put up on the Web (temporarily: they won't be there forever) three screen snaps: Please go to http://www.vex.net/~slocombe/fgfs-pics-of-CYTZ/ for pictures illustrating the problems of CYTZ (Toronto/City Centre), which is on an island in Lake Ontario just offshore from Toronto's downtown area. 1. cytz-from-08-apprch.png : CYTZ from the approach viewpoint of Runway 08 (08/26 is the principal runway of this extremely busy airport: Bombardier Dash8-Q400's take off or land about every 20 minutes, and in between that traffic Cessna 150's and 172's practise circuits or transit to/from Toronto's practice area to the East. I'm one of the student pilots these days. The fact that, in fgfs, the water is 240 feet below its real-world level is only a small part of the problem (in fact if that were the only problem one could just pretend one is practising landings on aircraft carriers). The terrain data, intersected by the water at its current level, makes the shoreline wildly wrong... 2. cytz-overhead-at-40Kft.png : This is taken with the UFO tool at 40,000 ft., looking straight down. 3. google-image-cytz.png : a snap of what Google has for a satellite shot, to compare with the previous shot. I'm not convinced that the terrain data that fgfs uses is sufficiently detailed to capture even the approximate shape of the Toronto Islands (what CYTZ is on the Western end of), let alone the Leslie Spit and docklands to the East. So I'm not sure how different this is going to look if the water-level were correct. But surely it would make a difference, and there are 700 miles of shoreline for Lake Ontario, and another 800 miles for Lake Erie: all of this would be affected by a fix. I presume the shoreline in the St. Lawrence River near Montreal must be seriously wrong too. BTW, Just For Kicks, I can fly *under* CYTZ. It doesn't seem to do me damage, and fgfs doesn't even crash! :-) Thanks everyone for the great achievement that fgfs is. It was fgfs that got me sufficiently enthused about flying to decide to get my PPL. David Slocombe Toronto Canada. -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High Priority: fixing the Great Lakes...
Quite a few years ago we had a debate, because we had to choose between two sets of shoreline data: 1. GSHSS was very nicely detailed (every little cove and point), but about 1 mile off for the Great Lakes, leaving shoreline airports either far inland or floating in the middle of a lake. 2. Vmap0 was much lower resolution (only big bays and points), but actually had the Great Lakes shorelines in roughly the right place. Since I was doing most of the TerraGear coding that year, I forced through vmap0, but a lot of people objected -- I thought it was OK for the Toronto harbourfront, but I don't remember for certain, and I don't know what FlightGear is using now. All the best, David On Sun, Mar 28, 2010 at 5:18 PM, David Slocombe sloco...@vex.net wrote: On Sunday 2010-03-28 David Megginson wrote: Now, quite a few years later, the Great Lakes are still broken in our default scenery, and as a result, FlightGear looks ridiculous to any new user who comes and tries flying in near cities such as Toronto, Rochester, Buffalo, Cleveland, Detroit, Chicago, or Milwaukee. Sometimes pictures really *are* worth a thousand words. I think this is one of those times. I've put up on the Web (temporarily: they won't be there forever) three screen snaps: Please go to http://www.vex.net/~slocombe/fgfs-pics-of-CYTZ/ for pictures illustrating the problems of CYTZ (Toronto/City Centre), which is on an island in Lake Ontario just offshore from Toronto's downtown area. 1. cytz-from-08-apprch.png : CYTZ from the approach viewpoint of Runway 08 (08/26 is the principal runway of this extremely busy airport: Bombardier Dash8-Q400's take off or land about every 20 minutes, and in between that traffic Cessna 150's and 172's practise circuits or transit to/from Toronto's practice area to the East. I'm one of the student pilots these days. The fact that, in fgfs, the water is 240 feet below its real-world level is only a small part of the problem (in fact if that were the only problem one could just pretend one is practising landings on aircraft carriers). The terrain data, intersected by the water at its current level, makes the shoreline wildly wrong... 2. cytz-overhead-at-40Kft.png : This is taken with the UFO tool at 40,000 ft., looking straight down. 3. google-image-cytz.png : a snap of what Google has for a satellite shot, to compare with the previous shot. I'm not convinced that the terrain data that fgfs uses is sufficiently detailed to capture even the approximate shape of the Toronto Islands (what CYTZ is on the Western end of), let alone the Leslie Spit and docklands to the East. So I'm not sure how different this is going to look if the water-level were correct. But surely it would make a difference, and there are 700 miles of shoreline for Lake Ontario, and another 800 miles for Lake Erie: all of this would be affected by a fix. I presume the shoreline in the St. Lawrence River near Montreal must be seriously wrong too. BTW, Just For Kicks, I can fly *under* CYTZ. It doesn't seem to do me damage, and fgfs doesn't even crash! :-) Thanks everyone for the great achievement that fgfs is. It was fgfs that got me sufficiently enthused about flying to decide to get my PPL. David Slocombe Toronto Canada. -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High Priority: fixing the Great Lakes...
David Megginson wrote: Quite a few years ago we had a debate, because we had to choose between two sets of shoreline data: Nowadays we're in the fortunate position of being able to merge land cover data from various sources. The foundation is still VMap0 which I've loaded into a PostGIS database, but a noticeable amount of land cover has either been edited in-place, right on the DB - or simply replaced. The names to remember in this context (in chronological order) are: Ralf Gerlich, John Holden, Christian Schmitt, Gijs de Rooy and Rainer Fischer (did I miss anyone ?). Even though there's still a huge lot to improve, these guys have already done a wonderful job so far ! If anyone feels like adding to this effort, either get in contact with Christian or John - or me. As a nice sample, look at this visual comparison. Before: http://mapserver.flightgear.org/map/?lon=-71.47911lat=41.61493zoom=11layers=0B0TTFFF After: http://mapserver.flightgear.org/map/?lon=-71.47911lat=41.61493zoom=11layers=B00TTFFF Here's the legend: http://wiki.osgeo.org/wiki/LandcoverDB_CS_Detail Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High Priority: fixing the Great Lakes...
Very nice work! I remember when all land cover in FlightGear (other than runways) was desert -- not sure why Curt picked a desert texture (I think it had something to do with Prescott, AZ). Next, we were able to separate land (always forest) from water. It's come a long way since then. All the best, David -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] High Priority: fixing the Great Lakes...
David Megginson wrote: [...] Next, we were able to separate land (always forest) from water. reminds me of the history of Creation :-) Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -- -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
