distance to the horizon
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molesworth wrote:
You should also be adjusting for atmospheric refraction!
That's true, if you want complete precision, but I was going for an approximation...
Graham Bradshaw wrote:
That's true, if you want complete precision
it really is not that difficult. We've been doing angle of deflection for visible and IR for ages. :) handy when you start in optics. :)
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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Muhadeeb66 wrote:
how far i can put a drilling platform so it won't be seen from shore.
If your the kind of person with the authority to be positioning a drilling platform, you should probably already know this. (Or at least have people working for you who can tell you). Or are you considering building an illegal drilling platform at don't want the police on the shore to spot it? :laugh:
Simon
Simon Stevens wrote:
If your the kind of person with the authority to be positioning a drilling platform, you should probably already know this.
I only place ships, and **I** know this, can visualize, calculate it in real-time and map it with tidal fluctuations for the next month....
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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I don't suppose you know how to derive those formulas...
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
dan neely wrote:
I don't suppose you know how to derive those formulas...
what do you need? tangential visibility on the WGS-84 ellipsoid or Clarke-1866 ellipsoid? :-D
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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You haven't given enough information for me to give you a completely correct answer. I'll need: 1. direction you are looking, and your lattitude (the Earth is not spherical, as you say) 2. position of Sun and Moon (for the tides) 3. current air pressure (also affects sea level) 4. Wind speed and direction (for waves) :laugh:
Graham Bradshaw wrote:
current air pressure (also affects sea level)
air-pressure, and temperature also affect the incident of refraction for the atmosphere. It isn't an illusion, some days you can see part way over the common horizon, especially on cold mornings when the pressure is right. :)
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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*sigh* I meant to type the eyeheight of the observer, my brain's on vacation today, and I'm not going to get a chance to follow it in any form for 10 more days.
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
dan neely wrote:
eyeheight
eyeheight sir! :-D
dan neely wrote:
my brain's on vacation today, and I'm not going to get a chance to follow it in any form for 10 more days.
com'on... if I can survive a 6 hour meeting with my sanity more or less the same (we won't say normal here), you can swing it! :-D mental vacation is better than none at all! :-D
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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just paint the whole thing sky blue...then it will blend into the background ;)
Steve
Steve Mayfield wrote:
just paint the whole thing sky blue...then it will blend into the background
just paint it alpha 0 and glBlendFunc(GL_SRC_ALPHA,GL_ONE); :) it always worked for me.
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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dan neely wrote:
I don't suppose you know how to derive those formulas...
what do you need? tangential visibility on the WGS-84 ellipsoid or Clarke-1866 ellipsoid? :-D
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
I'd settle for deriving the perfect sphere approximation model actually. Working off an ellipsoid doesn't help when the only data I have is planet/moon/large asteroid/etc has a radius of Y. Also there's a reasonable chance I'll be able to remember how to derive the spherical model when I need it again...
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
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OK, put your thinking caps on. What is the distance that one can see an object that is 250 feet tall, from the shore. acceptable answers will be an average, considering the earth is an oblate spheroid. The reason is, I would like to know how far i can put a drilling platform so it won't be seen from shore.
Tomorrow will be better than today, even better than yesterday
If I'm not wearing my glasses, a mile or so would be sufficient. More seriously, if you've ever been to Southern California, it's hard to see even the close in platforms, especially if there's any haze at all. (At time, unless you know the locations of the platforms, it's not clear whether you're seeing cargo and Navy ship traffic or platforms.)
Anyone who thinks he has a better idea of what's good for people than people do is a swine. - P.J. O'Rourke
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I'd settle for deriving the perfect sphere approximation model actually. Working off an ellipsoid doesn't help when the only data I have is planet/moon/large asteroid/etc has a radius of Y. Also there's a reasonable chance I'll be able to remember how to derive the spherical model when I need it again...
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
dan neely wrote:
I'd settle for deriving the perfect sphere approximation model actually.
Email me what you need Dan. I can do more than talk theory if we go .mil email. Otherwise I think I can point you in the directions you need. What have you got and what do you need out of it?
_________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb) John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
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http://en.wikipedia.org/wiki/Horizon
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