Date: Feb 15, 2009 11:28 AM
Author: ulas
Subject: Re: polygon creation from lat lon info

This polygon is in a Lambert Conformal projection. i ve the central lat lon and truelat 1  and 2 info of the projection. does this information help?

Ulas

Walter Roberson <roberson@hushmail.com> wrote in message <q1Xll.8946$nu6.8246@newsfe21.iad>...
> ulas im wrote:
>

> > i am trying to create a polygon from four corners that i ve the lat lon info of.
> > the object is to create the polygon first and then check if a number of
> > points fall inside the polygon.

>
> Which geoid model?
> http://en.wikipedia.org/wiki/Geoid
>
> Do you have access to the symbolic toolbox? If not, then you will only
> be able to run the calculations -approximately-, and you are going to get
> the wrong answers for some points, especially if the polygon is extremely
> close to or straddles the North Pole or South Pole.
>
> Yes, the implication of my questions *is* that in order to solve this
> problem, you *must* take into account the curvature of the Earth.
> Latitude and Longitude are -spherical- measures, so the calculation of
> what is "inside" or "outside" must be done in spherical space.