• C

Geometrical algorithm

Can anyone provide me with an example of an algorithm to do the following conversion:

Input:
   Latitude / longitude coordinate on earth's surface
   Zoom level (from full world to a few miles across)
   X/Y pixel width of PC screen

Asusming this lat/lon point on earth is being viewed form a point in space perfectly Normal to the earth's suface:

Output:
   The X/Y point on the screen that the given input Lat/lon point maps to, given the above input data for zoom level and screen resolution.

I would also need a way to detremine if the lat/lon point is on the visible or hidden half of the earth (this is easy), and if hidden, figure out the last visible x/y point on the path from the previous visible point to the hidden point (more difficult).

Basically looking to map the spherical coordinates to rectangular coordinates.

Jeff
jeffs1Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

sateesh_babuCommented:
Why don't you come up with an small pseudo code or algorithm, and them ask about it rather than putting the homework assignment directly.

Babu
0
cookreCommented:
What sort of projection?
0
jeffs1Author Commented:
If I were to come up with the algorithm, I would be answering my ownb question... I cna do this, but I was hoping to take advantage of someone elses's experience here who make have done this already...

I am not looking for any particular projection (as in the paper world)... I have described above all necessary input criteria for the algorithm... just looking at the earth from a point in space normal to the surface of the earth.

Jeff
0
INTRODUCING: WatchGuard's New MFA Solution

WatchGuard is proud to announce the launch of AuthPoint, a powerful, yet simple, Cloud-based MFA service designed to eliminate the vulnerabilities that put your data, systems, and users at risk.

ozoCommented:
"Just looking at the earth from a point in space normal to the surface of the earth."

Does it matter which point in space?
0
jeffs1Author Commented:
Points in space along a vector "Normal" to the surface of the earth are all on a single line from the earth to infinity.  The point along the line that you are at is determined by the zoom level.
0
cookreCommented:
One presumes two input coordinates were intended - the stated observation point and the implied query point.

Also, it seems to me as if altitude IS needed.  After all, there's lots more below the horizon at 10km than at 1000km.
0
jeffs1Author Commented:
Yes altitude is necessary... I was calling it Zoom level, but input is the same...
0
deightonprogCommented:
you also need to take 'angle of vision' into account, i.e. what proportion of a persons vision the pc monitor represents.
0
moduloCommented:
Dear expert(s),

A request has been made to close this Q in CS:
http://www.experts-exchange.com/Community_Support/Q_20488805.html

Without a response in 72 hrs, a moderator will finalize this question by:

 - Saving this Q as a PAQ and refunding the points to the questionner

When you agree or disagree, please add a comment here.

Thank you.

modulo

Community Support Moderator
Experts Exchange
0
moduloCommented:
Saving this Q as a PAQ and refunding the points to the questionner

modulo

Community Support Moderator
Experts Exchange
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
C

From novice to tech pro — start learning today.