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( 3 / 437 )Just a little anecdote about importing Google Earth info into Civil 3D. I think the guys at Autodesk did a great job of helping Civil 3D users get their hands easily on imagery and elevation data from Google Earth. Hey it certainly helps us out for filling out the horizon on visualization projects. But here's an interesting snag that we discovered. It seems that Google Earth doesn't support elevations below 0! Now that may not be too much of a problem for most of you around the world but here in Israel and I think only in Israel (but I may be wrong) we have surface elevations going down to beyond 400 meters below sea level. The Dead sea located in the Jordan river valley is the lowest point on earth with elevations getting down to about -420 meters. As well, the sea of Galillee - what we call the Kinerret and the stomping grounds of Jesus gets down into the -200's. So here we are working on a project and wanted to bring in some elevation and imagery from Google Earth to help round out the detailed survey data we already had from the project developers and were shocked to find out when we tried to import from Google that there just weren't any elevations below zero. Please beware that I haven't really researched this in depth and possibly we have got it wrong, but for the few minutes we had to investigate we came to the conclusion that the guys at Google Earth probably just didn't think about it. As always - I've got to throw in something about aviation here - so here goes. Well if Google Earth doesn't support negative elevations what about the altimeter on an airplane? Again, most airplane instrument manufacturers assume that a typical airplane will be flying at least somewhere at or above ground level... right? So the alitmeter has its lowest elevation set at 0! Now consider you are flying a fighter jet down the Jordan rift valley just off the deck to avoid radar and of course get the full sense of speed - what is your altimeter reading? Friends of mine in the aerospace industry told me that we had to modify the altimeters to work below sea level - hold your breath... blub blub blub.
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( 3 / 384 )I just can't help it and feel compelled to relate a story that I just read on one of the online news sites this morning. The basics of the story are as such: An airplane belonging to one of the local Israeli operators which flies scheduled commuter flights between the center of Israel and Eilat was struck by lightning shortly after takeoff from Ben Gurion last night on it's way to Eilat to pick up passengers. It seems from the article that this was a dead-headed leg (empty of fare paying passengers) to Eilat. In any event the crew returned to Ben Gurion to inspect the aircraft and make sure that no damage was caused and then proceeded to Eilat to complete it's mission with no other problems. The rest of the article is irrelevant for the purposes of this post. What I loved was the talkback as a result of the article and the different directions it took. The comments can easily be segregated into 4 general threads. The first to respond made a reference to the legendary hit movie of the '80s Back to the Future. The threads and comments that followed it take off with a lively discussion of just how fast the plane would have needed to be flying at the precise time 1.5 gigawatts of enery struck it to throw the passengers and crew into a different decade. I got a kick out of this line of discussion. Especially since it got so many people responding. The second and always predictable response had of course to do with those who maintain that it is obvious that the lightning strike was a direct result of the plane operating on the Sabbath. Yes, there are still people who insist that the God factor was involved punishing or warning the wayward pilots and crew for their desecration of the Sabbath. Funny, but from reading the article there was no mention of the aircraft being operated during the Sabbath, but at least a few hours afterward. Bottom line, don't let facts get in the way of fanatic thinking. Its clear that all disasters or potential disasters, or even disasters that didn't happen are a direct result of the majority of Israelis who don't subscribe to a particular brand of religious fanatacism and are unwilling to realize that all of the countries woes could easily be prevented were we to keep the Sabbath and a long list of no less than 612 other commandments. Then of course lightning would not have struck the plane and nothing would have happened as a result. The fact that nothing did happen as a result is irrelevant. The 3rd thread which I love is related to the former Prime Minister Ehud Barak. The translation of "lightning" in hebrew is "Barak". Ehud Barak is now staging a political comeback and is getting a good amount of press lately. One talkbacker couldn't resist and stated that "Barak" is a menace to the country. Craftily leaving which "Barak" he was referring to ambiguous the discussion took off with responses varying from serious to hilarious about how "Barak" has been proven time and again to be a disaster on a national level. I am not going to reveal my political biases here. We'll wait and see if lightning strikes twice or not. Finally the 4th thread actually related to lightning and aircraft. A veteran stewardess makes a post about how common lightning strikes really are and how in general aircraft are designed with a coating of insulating material which protect the occupants and make it more of an unpleasant experience rather than a life threatening one. While I am not an expert on lightning striking aircraft, from what I know she is on the right track but not absolutely accurate from an engineering and physics point of view on the explanation. Leave it to the talkbackers to get into an intense debate around the inaccuracies of her explanation... In any event I enjoyed the comments. What I thought was particularly interesting is that the vast majority of talkbacks save for thread number 4 really had nothing to do with the issue at hand. Have a good week - Natan
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( 3 / 385 )I find it hard to believe but this morning's (Dec 31 2006) news reports of yet another collision between a passenger train and a tractor this time on the Jerusalem - Tel Aviv line. Luckily there were only minor injuries to some 30 some odd passengers. Over the past two years Israel has seen 2 fatal accidents with multiple fatalities at at-grade train intersections and numerous other clashes in the train's right of way.
After the first big accident some two years ago I decided to make a mock-up of an RDV scene to show how you can visualize the sight-distance problems associated with train/roadway at grade intersections: http://www.rdvsystems.com/samples/infra ... /index.htm
I as well took the time to go and visit with some of the leading rail engineers here in the country to better understand why the simple principles we apply to road design and sight distances doesn't apply to trains. While I have listened intently to their explanations of how a train can't possibly stop in time when sighting some type of hazardous situation on the rail in front of them - I still don't get it. Shouldn't the driver of a train have some sort of ability to see what is going on and be able to make a decision to stop the train safely (without hurting or killing people) if the unexpected happens? As many of you know I am also deeply involved in aviation, and I can't think of a similar type of situation where passenger safety is left to sheer luck as it seems to be in the local rail industry.
I went to the rail authority as well and talked with them about how visual analysis may in fact help them better plan for these types of situations. In fact there was some agreement on that matter and we even put together for them a simulation for an experimental system that they are working on which can detect intrusions at at-grade crossings and send a signal down the line far enough in advance for the driver to stop safely before the crash:
http://www.rdvsystems.com/samples/infra ... /index.htm
As well, as a result we are actually doing many more projects for the Israel Rail Authority helping them visualize new proposed rail corridors and long term projects, the results of one such project you can view here:
http://www.rdvsystems.com/samples/infra ... /index.htm
While I am happy that our solutions are in fact being used by the rail authority,(hey who doesn't want to sell their professional services), I am still bothered by the fact that decision makers still aren't able to see the benefits of 3D visualization, not just to make an effective presentation but to actually use the virtual models as safety planning tools to improve design and operational standards of transportation systems. I know they are going in the right direction, but it just kills me every time I hear another report of an accident that we could have predicted and possibly avoided or planned for in a better manner were we to use visualization tools more effectively.
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